Jiaying Qi1,2,3†Hongling Wei1†Ye Zhang1,2,3Xiaoqing Tang1,2,3Weixue Zhong1,2,3
Zhonghua Tang1,2,3Ying Liu1,2,3*
Dewen Li1,2,3*- 1College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, China
- 2Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, China
- 3Northeast Forestry University, Heilongjiang Provincial Key Laboratory of Ecological Utilization of Forestry-Based Active Substances, Harbin, China
The rhizosphere of soil is a highly dynamic environment involving interactions among plants, soils, and microorganisms. Microorganisms play a crucial role in facilitating plant growth and development. Acanthopanax senticosus (Rupr. & Maxim.) (A. senticosus) is an important medicinal plant in traditional Chinese medicine. However, the artificial cultivation of this species faces several challenges that have impeded the advancement of its industry. In this study, Bacillus proteolyticus (C1) and Bacillus fungorum (C2) were isolated from the rhizosphere soil of A. senticosus and identified through 16S rDNA gene sequencing. The objective was to investigate the effects of these two plant growth-promoting rhizobacteria (PGPR) on the growth, photosynthesis, and metabolism of A. senticosus. GC–MS and LC–MS were employed to screen for metabolic differences and quantify key medicinal active compounds such as eleutheroside B, chlorogenic acid, and eleutheroside E. The results indicated significant increases in plant height, leaf area, and basal diameter under C1 treatment by 81%, 10%, and 164%, respectively. A total of 29 distinct primary metabolites were detected; these metabolites enriched three common pathways where acid accumulation was significantly enhanced under C1 treatment in A. senticosus. Furthermore, 30 different phenolic compounds were identified within the phenylpropanoid biosynthesis pathway; notably, the main medicinal active substances exhibited substantial increases following C1 treatment in A. senticosus. Compared with control conditions (CK), there was a significant increase in the content of eleutheroside B and chlorogenic acid under C1 treatment (P < 0.05), with increases recorded at 346% and 183%, respectively. Additionally, yields of eleutheroside B, chlorogenic acid, and eleutheroside E in leaves from single A. senticosus plants treated with C1 showed marked improvements compared to CK conditions (P < 0.05), increasing by 466%, 259%, and 102%, respectively. These findings suggest that Bacillus proteolyticus (C1) exerts pronounced effects on promoting both growth parameters and metabolic processes within A. senticosus. This study provides a foundation for the development and application of medicinal plants based on their growth and metabolic characteristics.
Highlights
● The coordinated relationship between growth physiology and metabolism under the PGPR treatment is revealed.
● PGPR treatment triggered the activation of the phenylpropanoid biosynthetic pathway.
● PGPR could upregulate the biosynthesis of the main medicinal active substances.
1 Introduction
Soil microorganisms are a key part of the soil ecosystem. The plant–microbiota formed with plants plays an important role in nutrient absorption, disease resistance, and abiotic stress tolerance during plant growth and development (Mącik et al., 2020; Trivedi et al., 2020). Plant growth-promoting rhizobacteria (PGPR) are a kind of beneficial microorganisms existing in the rhizosphere of plants, which have growth-promoting effects on plants and can improve the stress resistance of plants (Rafique et al., 2023). Many genera of PGPR have been identified (Dong-mei et al., 2020), such as Bacillus, Brevibacillus, Pseudomonas, Agrobacterium, Burkholderia, Streptomyces, and Thiobacillu (Guo et al., 2020). Bacillus has received predominant attention in both research and commercial applications (Negi et al., 2024). Bacillus species, belonging to the family Bacillaceae, are rod-shaped aerobic or facultative anaerobic Gram-positive bacteria that can be isolated from various environments (Alhaddad et al., 2024). These bacteria are widely distributed in soil, water, air, and the surface of animals and plants and are important participants in the material cycle in nature (Hartmann et al., 2022). Tian et al. (2018) isolated a strain of Bacillus amyloliquefaciens TB6 from the rhizosphere of ginseng, which promoted the growth of ginseng roots by reducing the richness and diversity of fungi in the rhizosphere and increasing the activities of polyphenol oxidase and catalase after inoculation. Bacillus pumilus enhances the content of glycyrrhizic acid by increasing the expression of key enzymes (Xie et al., 2019). Although there are many studies on Bacillus species, there is still a large gap in the research on the effects of Bacillus species on medicinal plants.
Acanthopanax senticosus (Rupr. & Maxim.), also known as Siberian ginseng, has been recognized as a traditional medicinal and edible plant species in China for centuries (Li et al., 2016b). It belongs to the Araliaceae family in the Far East of Russia and Northeast Asian countries such as Korea, Japan, and China (Lee et al., 2019). The components of triterpenoid saponins, lignans, coumarins, flavones, polysaccharides, and volatile have been detected in A. senticosus (Lee et al., 2012; Li et al., 2016a). These substances have important health benefits, including anti-tumor (Chen and Huang, 2018), anti-inflammatory (Liu et al., 2013), cardioprotective (Guan et al., 2015), antioxidative (Załuski et al., 2018), antiedema (Fukada et al., 2016), and more. Among these, eleutheroside E and eleutheroside B are the primary active components, exhibiting significant health-promoting effects such as antioxidant, anti-inflammatory, immunomodulatory, antifatigue, and cardiovascular protective activities (Zhao et al., 2023b; Liu et al., 2024). Currently, the artificial cultivation industry of A. senticosus faces several challenges that have resulted in the slow development of the industry, including a long natural growth cycle, difficult cultivation, low yield, and mixed quality (Zhang and Li, 2021). Consequently, there is an urgent need to develop efficient cultivation strategies or identify alternative sources with similar bioactive profiles to ensure the sustainable utilization of these valuable plant resources (You et al., 2025). Relevant departments attached great importance to the protection of wild A. senticosus resources. They encouraged the development of the artificial cultivation industry of A. senticosus. The rational development and utilization of A. senticosus had become the primary task of current research (Song, 2022). Therefore, applying PGPR to promote the growth of A. senticosus has practical significance.
Two different Bacillus species were therefore isolated from the rhizosphere soil of A. senticosus in this study, with the objectives to (a) identify the selected growth-promoting rhizobacteria obtained from A. senticosus through molecular and phylogenetic identification and (b) evaluate the efficacy of two bacterial strains to improve seedling growth and the metabolism aspects of A. senticosus under irrigation.
2 Materials and methods
2.1 Screening and identification of strains
The rhizosphere soil of A. senticosus was collected using the shaking method (Riley and Barber, 1970). The soil samples were mixed and placed into sterile plastic zip-seal bags, which were then transported to the laboratory for strain isolation. Based on the optimization results of strain isolation conditions, 1 g of A. senticosus rhizosphere soil was weighed and added to a flask containing 99 mL of sterile water along with glass beads. This mixture was subjected to shaking at 37°C and 180 r/min for 40 minutes to ensure thorough mixing. After allowing it to stand for 5 min, the resulting soil suspension was diluted in a gradient dilution series (1:5 to 1:10) and evenly spread onto agar plates. Following this, five to 10 replicates were established, and the plates were incubated in a constant-temperature incubator at 37°C for 24 h. Single colonies exhibiting vigorous growth and distinct colony morphologies were selected for streak plate isolation and culture; this process was repeated three to four times until purified strains were obtained and numbered accordingly. Once cultured in liquid media, these pure strains were prepared as glycerol stocks and stored at -20°C under low-temperature conditions for future use.
The molecular identification of two selected strains was performed by analyzing 16S rDNA gene sequences (Weiji Biotechnology, Shanghai). Proteinase K digestion method was adopted to extract the genomic DNA of selected strains. PCR amplification was performed using primers (5′-AGAGTTTGATCCTGGCTCAG-3′) and the downstream primer (5′-AAGGAGGTGATCCAGCC-3′) targeting the V1–V9 region of 16S gene. The PCR amplification cycles were as follows: denaturation at 94°C for 2 min, followed by 27 cycles of 94°C for 30 s, 56°C for 30 s, 72°C for 90 s, and then at 72°C for 5 min. The amplification products were detected by using agarose gel electrophoresis, and successful amplification was confirmed for sequencing. The sequencing results were subjected to the NCBI database (https://blast.ncbi.nlm.nih.gov/Blast.cgi) for sequence homology analysis. As shown in S1, neighbor-joining method was employed to construct a phylogenetic tree (bootstrap = 1,000) by Mega10.1.8 (Molecular Evolutionary Genetics Analysis 10.1.8). Visualization of the tree was processed using R package (version 2.0.4).
2.2 Experimental treatment
2.2.1 Preparation of microbial agents
An individual colony of each strain was transferred to an Erlenmeyer flask containing 100 mL of sterile LB liquid medium and incubated at 37°C for 8–10 h with shaking at 200 rpm. Following centrifugation at 5,000 rpm, the supernatant was removed, and the bacterial cells were washed three times with sterile water. The bacterial pellet was then resuspended in sterile water to prepare the bacterial inoculum, which was stored at 4°C for further use.
2.2.2 Experimental design
A pot experiment was conducted in the greenhouse facilities of the Key Laboratory of Forest Plant Ecology, Ministry of Education, at Northeast Forestry University (latitude: 45.75° N, longitude: 126.63° E). Two-year-old potted A. senticosus seedlings grown from seeds were used as experimental materials. Uniformly vigorous seedlings exhibiting consistent growth patterns were carefully selected and transplanted into individual plastic pots (diameter: 15 cm, height: 14 cm). The growth medium consisted of a mixture of nutrient soil and sand in a 3:1 ratio. A total of 90 2-year-old potted A. senticosus seedlings with uniform growth were randomly assigned to three treatment groups: Bacillus proteolyticus (C1), Bacillus fungorum (C2), and an untreated (CK). Seedlings in the C1 and C2 groups were irrigated weekly with 200 mL per pot of their respective microbial inoculants via root drenching, while the CK group received an equivalent volume of distilled water. The experiment spanned 60 days, from early May to late July, during which all plants were maintained under standardized conditions with regular watering and nutrient supply to ensure consistent management across treatments.
2.3 Measurement of growth indicators
Plant height measured with a ruler (precision, 1 mm) was measured with a vernier caliper for leaf thickness, leaf area was calculated according to the tracing number grid method, and fresh weight was determined with an electronic balance. Measurements of the aforementioned indicators were conducted throughout the sampling process to assess changes in each parameter. Leaf fresh weight (FW) and leaf area were measured, after which the leaves were dried at 70°C until a constant mass was achieved, and the dry weight of the leaves (DW) was recorded. The leaf water content (WC) was calculated using the following equation: WC% = (FW - DW)/FW × 100%.
2.4 Measurement of photosynthetic characteristics
2.4.1 Measurement of photosynthetic pigment content
Fresh samples were accurately weighed to 0.10 g, placed in test tubes, and treated with 5 mL of 95% ethanol before being incubated overnight at 4°C. Absorbance values at wavelengths of 480, 645, and 663 nm were determined using a UV–visible spectrophotometer (UV-2600, Shimadzu, Japan), with all assays performed under dark conditions. The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids (Car), and total chlorophylls (Chl) were calculated according to established formulas:
Chl a concentration (Ca) = 12.7 × A663 - 2.69 × A645
Chl b concentration (Cb) = 22.9 × A645 - 4.68 × A663
Car concentration (Cx.c) = (1,000A480 - 3.27Ca - 104Cb)/229
Chl a content (mg·g 1) = Ca × V/FW
Chl b content (mg·g 1) = Cb × V/FW
Car content (mg·g 1) = Cx.c × V/FW
Chl content (mg·g 1) = Chl a + Chl b
Chl a/b ratio = Chl a/Chl b
Note that A663, A645, and A480 indicate the absorbance values at 663, 645, and 480 nm, respectively, and V indicates the 95% ethanol volume (mL). FW indicates the sample fresh weight (g).
2.4.2 Measurement of photosynthesis and chlorophyll fluorescence parameters
The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) for each treatment were measured using a portable photosynthetic meter LICOR-6400 (LI-6400-09, LiCor, Lincoln, NB, USA) between 9:00 AM and 11:00 AM.
A portable PAM-2500 chlorophyll fluorometer (Heinz Walz GmbH, Effeltrich, Germany) was employed to determine various chlorophyll fluorescence parameters. Initial fluorescence (F0), maximum fluorescence (Fm), non-photochemical quenching ratio (NPQ), photochemical quenching ratio (qP), photosynthetic electron transfer rate (ETR), maximum photosynthetic efficiency ratio (Fv/Fm), and actual photosynthetic efficiency of PSII (Y(II)) were measured after adapting A. senticosus leaves in darkness for 20 min.
2.5 Measurement of metabolism
The sample preparation method for the primary medicinal active constituents was conducted as follows: 0.5 g of fresh A. senticosus leaves were weighed and transferred into a 10-mL test tube. Subsequently, 8 mL of chromatographic-grade methanol was added, and the mixture was vortexed in a grinder for 2 min. Following this step, the samples underwent ultrasonic extraction for 45 min, followed by low-temperature centrifugation at 4°C for 10 min. The supernatant was carefully collected and filtered through a 0.25-μm microporous membrane in preparation for HPLC analysis. The polyphenol determination method (LC-MS) was performed according to Fei et al. (Feiyang et al., 2023). The methods used to determine the content of the main medicinal active substances (HPLC) and primary metabolites (GC–MS) were based on those described by Liu (2023). The contents of three principal medicinal active substance standards were analyzed, establishing linear regression equations between their concentrations and peak areas to generate standard curves and verify linearity. The standard curve equations for the target compounds are summarized in Supplementary Table S3.
2.6 Statistical analysis
The significance of differences among groups was assessed using one-way analysis of variance (ANOVA) with SPSS version 26.0 statistics software (SPSS Inc., Chicago, IL, USA), employing Duncan’s post hoc test for comparisons; differences were considered statistically significant when P <0.05. All data are expressed as mean ± standard deviation (SD). For multivariate analysis, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), the SIMCA 14.1 software (Umetrics, Umeå, Sweden) was utilized to examine variations in the metabolite profiles under different SM treatments. Variable importance charts (VIP) >1 and |log2 fold change (FC)| ≥1 were considered to distinguish significantly different metabolites. The metabolic pathway of differential accumulated metabolites (DAMs) was carried out by using Kyoto Encyclopedia of Genes and Genomes (KEGG). Graphics and tables were prepared using Origin (version 2024, Microcal Software, Northampton, MA, USA) and Excel 2021.
3 Results
3.1 Identification of strains
Two strains of colonies promoting the growth of A. senticosus were selected through preliminary experiments, with their respective colony characteristics observed (Figure 1). The C1 strain exhibited creamy white colonies that were round, moist, and with smooth surfaces and neat edges after incubation at 28°C for 12 h. Conversely, the C2 strain displayed white colonies that were round, non-translucent with convex centers, and also had neat edges under identical conditions.
Figure 1. Morphological characteristics and Gram staining results of the strains.
Physiological and biochemical analyses are presented in S4, which revealed that the C1 strain was a Gram-positive bacterium (G+). The strain exhibited positive reactions for contact enzyme activity, oxidase presence, gelatin hydrolysis, methyl red test, starch hydrolysis, and nitric acid reduction. Conversely, the results of the V-P test, indole reaction, and H2S production were negative. Similarly, the C2 strain was also identified as a Gram-positive bacterium (G+). However, while it displayed positive results for contact enzymes and oxidases, all other tests—including gelatin hydrolysis, methyl red test, VP assay, starch hydrolysis, nitric acid reduction reaction as well as indole reaction and H2S production—yielded negative outcomes.
To further elucidate the species and genus classification of these strains, PCR amplification followed by sequencing was conducted. As illustrated in S5, a comparative analysis against NCBI databases revealed that the C1 strain shared an astonishing 100% similarity with Bacillus proteolyticus strain MCCC 1A00365 (NR_117735), whereas the C2 strain demonstrated an identical 100% similarity with Bacillus fungorum strain 17-SMS-01 (NR_170494). The sequencing data have been uploaded to the NCBI database for BLAST comparison; additionally, a phylogenetic tree was constructed utilizing the neighbor-joining method within MEGA 6.0 software (S6). Consequently, based on colony morphology, the C1 strain has been tentatively classified as Bacillus proteolyticus, while the C2 strain was designated as Bacillus fungorum.
3.2 Analysis of growth indicators and photosynthetic characteristics
As shown in Table 1, when compared to the CK group, significant enhancements were observed in plant height, basal diameter, leaf area, and leaf fresh weight of A. senticosus under C1, increased by 81%, 164%, 10%, and 8%, respectively (P < 0.001). Under treatment with C2, the plant height and leaf fresh weight of A. senticosus were significantly increased by 37% and 5%, respectively (P < 0.001). The leaf fresh weight was significantly increased by 4% under C2 (P = 0.028). Notably, leaf thickness along with water content showed a marked elevation in response to treatment with C2, with increases recorded at rates of 33% and 25%, respectively (P < 0.001), while treatment with C1 resulted in comparatively modest improvements of only 14% and 22%.
Table 1. Growth indexes and photosynthetic pigment contents in A. senticosus among different treatments.
The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (Chl), and carotenoids (Car) in A. senticosus leaves were significantly increased under C1 treatment by 67%, 114%, 83%, and 68%, respectively (P < 0.001). Under the treatment with C2, the content of Chl b was significantly increased by 28% (P = 0.022). However, no significant differences were observed in the contents of Chl a, total chlorophyll (Chl), and carotenoids (Car) between the C2 treatment and the CK (P > 0.05). Compared with the CK group, the Chl a/Chl b ratio was significantly reduced by 22% under C1 treatment (P = 0.011) and by 25% under C2 treatment (P = 0.007).
3.3 Analysis of photosynthetic characteristics
As shown in Table 2, compared with the CK group, Pn, Gs, Ci, and Tr of A. senticosus were significantly increased under C1 treatment by 34%, 155%, 73%, and 37%, respectively (P < 0.001). Under C2 treatment, the parameters of Pn, Tr, and Ec were significantly increased by 27%, 11%, and 46%, respectively (P < 0.001). Gs, Ewu, and Ls were increased by 10% (P = 0.002), 14% (P = 0.004), and 8% (P = 0.01), respectively. However, Ci was significantly reduced by 9% under C2 treatment (P = 0.01), and Ewu, Ec, and Ls were significantly reduced by 2%, 23%, and 44%, respectively, under C1 (P < 0.001).
Table 2. Photosynthetic rates and gas exchange parameters in A. senticosus among different treatments.
As shown in Table 2, no significant differences were observed in the maximum photosynthetic efficiency (Fv/Fm), the non-regulatory energy dissipation (YNPQ), and the regulatory energy dissipation (YNO) between the treatment groups and the CK group (P > 0.05). Compared with the CK, the non-photochemical quenching coefficient (NPQ), the photochemical quenching coefficient (qP), and the electron transfer rate (ETR) of A. senticosus were significantly increased under C1 treatment by 15% (P < 0.001), 50% (P = 0.018), and 18% (P = 0.002), respectively. Under C2 treatment, these parameters increased by 5% (P = 0.019), 23% (P < 0.001), and 42% (P < 0.001), respectively. There was no significant difference in the actual photosynthetic efficiency Φ(II) between C2 and CK, but it was significantly increased by 43% under the C1 (P < 0.001).
3.4 Analysis of metabolism
3.4.1 Analysis of primary metabolism
To comprehensively assess the overall distinctions among the three groups, we conducted principal component analysis (PCA) alongside hierarchical clustering analysis (HCA). The PCA distinctly separated treatments C1 and C2 from CK, as depicted in Figure 2A. Utilizing the first principal component (PC1, accounting for 80.53% of variance) and the second principal component (PC2, contributing 17.55%), it became evident that treatments C1 and C2 could be categorized into two distinct clusters, indicating unique metabolite profiles for each group.
Figure 2. PCA, OPLS-DA model, and classification in A. senticosus among different treatments.
The orthogonal partial least squares discriminant analysis (OPLS-DA) model was employed to elucidate the metabolic characteristics distinguishing the C1 and C2 treatments. The predictive parameters of the OPLS-DA model were R²X, R²Y, and Q², which served as indicators of model stability and reliability, with values approaching 1 signifying a robust framework. In this analysis, the scores for R²Y and Q² were recorded as 0.998 and 0.996, respectively (Figure 2B), thereby affirming the appropriateness of the model. Notably, a clear separation between the C1 and C2 treatments was observed within the OPLS-DA framework (Figure 2C), underscoring significant disparities in metabolic substances between these two conditions.
Built upon insights gleaned from the OPLS-DA model, we identified differential accumulation metabolites (DEMs) based on criteria including variable importance in projection (VIP >1) and fold change thresholds (FC >2 or FC <0.5), alongside P < 0.05, when comparing C1 treatment to that of C2. A total of 29 distinct metabolites emerged across three groups (S7), which could be categorized into five primary classes—acids (55.17%), alcohols (20.69%), taxanes (10.34%), carbohydrates (10.34%), and anilines (3.45%)—as illustrated in Figure 2D.
As shown in Figure 3, a pronounced delineation between the C1 and C2 treatments was evident on the heatmap, which indicated substantial differences in metabolite concentrations across these experimental conditions. These findings were consistent with those derived from the principal component analysis (PCA). The heatmap further revealed a marked increase in acidic compound accumulation under C1, which encompassed 11 specific acids, namely: octanoic acid, acetic acid, sulfurous acid, stearic acid, malic acid, 2-ethylbutyric acid, phosphoric acid, propanoic acid, palmitic acid, 2-propenoic acid, and butanoic acid. Conversely, under C2 treatment, there was a notable elevation in both carbohydrate levels (including d-glucose sucrose and sedoheptulose) and alcohol levels (such as 2-butanol, 3-chloro-1,2-propanediol, erythritol, and muco-inositol).
Figure 3. Hierarchical cluster analysis of the primary metabolites identified in A. senticosus among different treatments. The contents of different metabolisms are from low to high and from blue to red.
The differential metabolic profiles identified were subsequently imported into the MetaboAnalyst 5.0 online analysis platform, with the Arabidopsis database selected for comprehensive KEGG metabolic pathway analysis. The results of the KEGG analysis concerning various metabolites in A. senticosus subjected to distinct treatments are illustrated in Figure 4. Six metabolic pathways were significantly enriched in CK_VS_C1 (Figure 5a); these were starch and sucrose metabolism, biosynthesis of unsaturated fatty acids, pyruvate metabolism, galactose metabolism, glyoxylate and dicarboxylate metabolism, and fatty acid biosynthesis. Six metabolic pathways were significantly enriched in CK_VS_C2 (Figure 5b); these were galactose metabolism, glyoxylate and dicarboxylate metabolism, butanoate metabolism, propanoate metabolism, citrate cycle (TCA cycle), and starch and sucrose metabolism. Six metabolic pathways were significantly enriched in C1_VS_C2 (Figure 5c); these were galactose metabolism, glyoxylate and dicarboxylate metabolism, citrate cycle (TCA cycle), starch and sucrose metabolism, pyruvate metabolism, and alanine, aspartate, and glutamate metabolism. Among them, glyoxylate and dicarboxylate metabolism, starch and sucrose metabolism, and galactose metabolism pathways were common to CK_VS_C1, CK_VS_C2, and C1_VS_C2. Combined with the screened differential metabolic pathways, the accumulation of primary metabolisms could be promoted under C1 and C2 treatments by promoting the metabolic pathways in A. senticosus, such as acids, carbohydrates, and so on.
Figure 4. Hierarchical cluster analysis of the secondary metabolisms identified in A. senticosus among different treatments. The contents of different metabolites are from low to high and from blue to red.
Figure 5. (a–c) Bubble map of the KEGG pathway enrichment of DEMs in A. senticosus among different treatments. The depth of the color represents the size of the P-value; the darker the color, the greater the P-value and the higher the accumulation of differential metabolites.
Significant differences were observed in the physiological indicators and primary metabolite contents of plants subjected under C1 treatment (Figure 6). Specifically, significant correlations emerged between the levels of lactic acid, 3-chloro-1,2-propanediol, malonic acid, glycerol, erythritol, isovaleric acid, sucrose, d-glucose, heptane, sedoheptulose, 2-butenoic acid, muco-inositol, and 2-butanol with plant height, leaf area, and leaf fresh weight (P < 0.05). Moreover, the same set of metabolites (excluding lactic acid) was significantly positively correlated with basal diameter. Lactic acid and glycerol levels were also significantly associated with leaf thickness (P < 0.05). In addition, hexane, palmitic acid, scyllo-inositol, butyric acid, and 2-butanol exhibited significant associations with leaf dry weight (P < 0.05); 2-propenoic acid was extremely significantly correlated with leaf dry weight (P < 0.001), which possibly reflected the contributions of biomass accumulation. Notably, lactic acid, glycerol, and malic acid were extremely significantly correlated with moisture content (P < 0.001). Sucrose, sedoheptulose, and 2-butanol were significantly correlated with moisture content (P < 0.05).
Figure 6. Correlation analysis between growth index and primary metabolisms. *significant difference (P < 0.05); **significant difference (P < 0.01); ***very significant difference. Blue is a negative correlation and red is a positive correlation.
3.4.2 Analysis of secondary metabolisms
As shown in Figure 4, a total of 30 phenolic compounds were discerned within A. senticosus. Of these compounds, 17 demonstrated heightened accumulation levels under the C1 treatment, including daidzein, gentistein, qurercetin, p-hydroxycinnamic acid, luteolin, ferulic acid, rutin, chrysin, vanillic acids, catechin, naringenin, cinnamic acid, kaempferol, caffeic acid, l-phenylalanine, sinapic acid, and isoquercetin. In stark contrast, elevated contents of 11 compounds were significantly noted under C2 treatment, namely: abscisic acid liquiritin, isoliquritigenin, protocatechin, vetch glycoside, trigonelline, galangin, naringin, genistin, syringic acid, and gentisic acid.
The KEGG analysis of differential metabolites in A. senticosus among different treatments is presented in Figure 7. Three metabolic pathways—flavone and flavonol biosynthesis, phenylpropanoid biosynthesis, and flavonoid biosynthesis—were significantly enriched in the comparisons C1_VS_CK, C2_VS_CK, and C1_VS_C2. Notably, the flavonoid biosynthesis pathway is a specialized branch within the broader phenylpropanoid biosynthesis pathway.
Figure 7. (a–c) Bubble map of the KEGG pathway enrichment of different phenolic compounds in A. senticosus among different treatments. The depth of the color represents the size of the p-value; the darker the color, the greater the p-value and the higher the accumulation of differential metabolisms.
As shown in Figure 8, compared with CK, the contents of eleutheroside B were significantly increased under C1 (P < 0.001) and C2 (P = 0.023) treatments by 346% and 134%, respectively. The contents of chlorogenic acid were significantly increased under C1 and C2 treatments (P < 0.001) by 183% and 104%, respectively. The content of eleutheroside E had no significant difference under C1 and C2 treatments (P = 0.087).
Figure 8. Content and yield of the main medicinal active substances in A. senticosus among different treatments.
Compared with CK, the yields of eleutheroside B, chlorogenic acid, and eleutheroside E were significantly increased in A. senticosus under C1 treatment by 466% (P < 0.001), 259% (P < 0.001), and 102% (P = 0.007), respectively. These parameters under C2 treatment were increased by 183% (P = 0.009), 145% (P < 0.001), and 90% (P = 0.012), respectively. Therefore, the C1 treatment could significantly increase the yield of the main medicinal active substances in A. senticosus.
4 Discussion
4.1 Growth-promoting capacity of Bacillus strains
Bacillus is among the microorganisms which are employed in crop production as an excellent alternative to chemical fertilizers and pesticides (Bhadrecha et al., 2023). This beneficial bacterium could be used as a biological fertilizer and biocontrol agent for plant growth promotion and protection against pathogens (Daroodi et al., 2022). Bacillus are widely marketed and used in agricultural systems as antagonists to various phytopathogens, but it can also benefit the plant as plant growth promoters (De O. Nunes et al., 2023).
Currently, the Bacillus genus becomes a potential candidate for most agricultural and biotechnology applications (Miljaković et al., 2020). Zhao et al. (2023a) found that Bacillus proteinolyticus 133 could improve the activities of SOD and POD in soybean seedlings and its salt tolerance. Yang et al. (2023) found that Bacillus proteinolyticus could promote plant growth by changing the root structure and defense signals and reducing the biotic and abiotic stresses in Arabidopsis thaliana. Yi et al. (2022) found that Paenibacillus polymyxa (P. polymyxa) could produce a variety of metabolisms to promote the growth of Dendrobium nobile (D. nobile). Previous studies have demonstrated the positive effects of the application of Bacillus on plant yield (Mohamed et al., 2019). Similarly, Bacillus is well known for its ability to promote plant growth (Ji et al., 2022).
In this study, we investigated the effect of Bacillus on the growth and metabolism of A. senticosus, and its physiological mechanism was revealed. Combined with morphological and molecular identification, the C1 strain was identified as Bacillus proteinolyticus and the C2 strain as Bacillus fungiformis (Figure 3), both of which belong to the Bacillus genus in this study. The plant height, leaf area, and leaf fresh weight of A. senticosus were significantly increased (P < 0.05) under the C1 and C2 treatments, but the growth-promoting effect under the C1 treatment was better than that of the C2 treatment (Table 1). The results were consistent with the results of Shao et al. (2025).
4.2 Photosynthesis-promoting capacity of Bacillus strains
Photosynthesis is the most fundamental metabolic activity in all green plants, and it plays an important role in the growth and development of plants (Doubnerová and Ryšlavá, 2011). It is through photosynthesis that plants can produce and store nutrients (Freschi and Mercier, 2012). Photosynthesis is severely affected in all of its phases by different stresses. Since the mechanism of photosynthesis involves various components, including photosynthetic pigments and photosystems, the electron transport system, and the CO2 reduction pathways, damage at any level caused by a stress may reduce the overall photosynthetic capacity of a green plant (Ashraf et al, 2013). Both abiotic (Zhong et al., 2022; Todorova et al., 2022) and biotic (Zhang et al., 2022) stresses can influence the photosynthesis of plants. Under drought and flooding stress, the growth of the plants will be hindered, and the photosynthetic capacity of the plants will be reduced (Zhong et al., 2022; Todorova et al., 2022).
Rhizobacteria are able to improve plant photosynthesis because of increase in stomatal conductance and enhanced photochemical efficiency under abiotic stress (Zhang et al., 1997; Gururani et al., 2013). Promoting photosynthesis is a crucial element in achieving high crop yields in fruit and vegetable production (Gai et al., 2023). Leaf lamina mass and area are closely correlated with the photosynthetic capacity and competitive ability of plants, whereas leaf age has been demonstrated to affect physiological processes such as photosynthesis (Jiao et al., 2022). In this study, the leaf area of A. senticosus was significantly increased under C1 treatment (Table 1). It was consistent with the results of Jiao et al. Chlorophyll fluorescence indices were reported by Neshat et al. (2022), and RWC increased significantly in PGPR-inoculated treatments (Neshat et al., 2022). Simultaneous inoculation with bushy mycorrhizal fungi and inter-root bacteria has been proven to enhance the efficiency of photosynthesis and increase the content of photosynthetic pigments, leading to the growth promotion of tobacco plants (Begum et al., 2022). As shown in Table 1, the contents of Chl a and Chl b were significantly increased under C1 treatment. It was consistent with the results of Begum et al. Under conditions of drought stress, PGPR can modify the fundamental structure and functional characteristics of a plant’s photosynthetic system by generating phytohormones that enhance stomatal conductance and the photosynthetic rate (Gowtham et al., 2022). As shown in Table 2, the Pn and Gs of A. senticosus were significantly increased under C1 treatment. It was consistent with the results of Gowtham et al. These results indicated that the C1 strain exerted the most effective photosynthesis-promoting effect on A. senticosus.
4.3 Metabolism-promoting capacity of Bacillus strains
The higher accumulation of primary and secondary metabolites in plant tissues in many plant–microbe interactions plays an important role in enabling plant growth and tolerance to abiotic and biotic stresses (Fontana et al., 2021). Bacillus not only contributed to plant growth but also played an important role in the synthesis of secondary metabolisms (Semwal et al., 2023). Phenylpropanoid metabolism plays a very important function in the biosynthesis of cell wall components (Olivares-García et al., 2020; Hoech et al., 2021). Many relevant studies have proved that microorganisms promote plant growth by enhancing phenylpropane metabolisms, such as Bacillus pumilus LZP02 which promoted the growth of rice roots by enhancing carbohydrate metabolism and phenylpropanoid biosynthesis (Liu et al., 2020).
As shown in Figure 9, L-phenylalanine was subjected to PAL to generate cinnamic acid, which further reacted to caffeic acid, ferulic acid, and sinapic acid in turn. Sinapic acid was formed into eleutheroside B by sinapine–coenzyme A, and chlorogenic acid was the intermediate product of caffeic acid to eleutheroside E. Compared with the CK, all six compounds involved in the phenylpropanoid biosynthesis pathway—ferulic acid, cinnamic acid, p-hydroxycinnamic acid, sinapic acid, L-phenylalanine, and caffeic acid—were significantly upregulated under C1 treatment (P < 0.05). These results indicated that the accumulation of key intermediates was increased in the phenylpropanoid pathway under C1 treatment, thereby increasing the levels of main medicinal substances, including eleutheroside B, eleutheroside E, and chlorogenic acid, in A. senticosus. The results show that Bacillus proteinolyticus could promote the accumulation of the main medicinal active substances, and it was consistent with the results of Zhao et al. (2016).
Figure 9. Phenylpropanoid biosynthesis pathway (Wang, 2023).
In conclusion, it was revealed that not only was the growth of A. senticosus stimulated under C1 treatment but also the secondary metabolism was promoted. Therefore, the results indicated that Bacillus proteolyticus (C1) had better effects on promoting the growth and metabolism of A. senticosus. The plant height, leaf area, and leaf fresh weight were significantly correlated with multiple primary metabolisms (Figure 7). It was shown that the Bacillus primarily utilized the glyoxylate and dicarboxylate metabolism pathways to produce large amounts of organic acids to promote plant growth, and it was consistent with the results of Tian et al. (2024).
5 Conclusion
This study demonstrated that inoculation with Bacillus proteolyticus (C1) and Bacillus fungorum (C2) significantly enhanced the growth of A. senticosus by upregulating the contents of metabolisms and enhancing the accumulation of main medicinal substances. The C1 strain increased the contents of photosynthetic pigments, the Pn and Gs of A. senticosus, thereby promoting photosynthesis. The changes of metabolisms were associated with a marked increase in plant biomass compared to the non-inoculated controls (CK). Mechanistically, the C1 inoculant stimulated plant growth by enhancing phenylpropane metabolisms and promoted the accumulations of main medicinal active substances (eleutheroside B, chlorogenic acid, and eleutheroside E). These findings provide valuable insights into how C1 inoculation promotes the growth of medicinal plant, suggesting that applying microbial bacterial fertilizers represents a promising strategy. Therefore, this study provided theoretical support for the promotion of medicinal plant growth and metabolism by Bacillus proteolyticus.
Data availability statement
The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.
Author contributions
JQ: Writing – original draft, Data curation, Visualization. HW: Data curation, Writing – original draft. YZ: Data curation, Writing – original draft. XT: Data curation, Writing – original draft. WZ: Data curation, Writing – original draft. ZT: Methodology, Writing – review & editing. YL: Methodology, Supervision, Writing – review & editing. DL: Funding acquisition, Methodology, Project administration, Resources, Supervision, Writing – review & editing.
Funding
The author(s) declared financial support was received for this work and/or its publication. This research was funded by National Key Research and Development Program of China (No.2022YFF1300503), The Science and Technology Basic Resources Investigation Program of China (No. 2019FY100500), Seed Industry Innovation Funds for Heilongjiang Province of China (ZQTYB231700002) and The Fundamental Research Funds for the Central Universities (No. 2572023CT11).
Conflict of interest
The authors declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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Supplementary material
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fagro.2025.1695649/full#supplementary-material
References
Alhaddad F. A., Bitaar Z. M., and Abu-Dieyeh M. H. (2024). Diversity, characterization, and potential applications of bacterial endophytes isolated from the halophyte Limonium axillare. J. Plant Growth Regul. 43, 2179–2196. doi: 10.1007/s00344-024-11254-6
Ashraf M. and Harris P. J. C. (2013). Photosynthesis under stressful environments: An overview. Photosynthetica 51, 163–190. doi: 10.1007/s11099-013-0021-6
Begum N., Wang L., Ahmad H., Akhtar K., Roy R., Khan M. I., et al. (2022). Co-inoculation of arbuscular mycorrhizal fungi and the plant growth-promoting rhizobacteria improve growth and photosynthesis in tobacco under drought stress by up-regulating antioxidant and mineral nutrition metabolism. Microb. Ecol. 83, 971–988. doi: 10.1007/s00248-021-01815-7
Bhadrecha P., Singh S., and Dwibedi V. (2023). ‘A plant’s major strength in rhizosphere’: the plant growth promoting rhizobacteria. Arch. Microbiol. 205, 165. doi: 10.1007/s00203-023-03502-2
Chen L. and Huang G. (2018). Antitumor activity of polysaccharides: an overview. CDT 19(1), 89–96. doi: 10.2174/1389450118666170704143018
Daroodi Z., Taheri P., and Tarighi S. (2022). Acrophialophora jodhpurensis: an endophytic plant growth promoting fungus with biocontrol effect against Alternaria alternata. Front. Plant Sci. 13. doi: 10.3389/fpls.2022.984583
De O. Nunes P. S., De Medeiros F. H. V., De Oliveira T. S., De Almeida Zago J. R., and Bettiol W. (2023). Bacillus subtilis and Bacillus licheniformis promote tomato growth. Braz. J. Microbiol. 54, 397–406. doi: 10.1007/s42770-022-00874-3
Dong-mei H., Hai W., Jin-long C., Chang-jiang-sheng L., Zhu-yun Y., and Lu-qi H. (2020). Microecology and geoherbalism of traditional Chinese medicine.
Doubnerová V. and Ryšlavá H. (2011). What can enzymes of C4 photosynthesis do for C3 plants under stress? Plant Sci. 180, 575–583. doi: 10.1016/j.plantsci.2010.12.005
Feiyang S. and Zhonghua T. (2023) in Regulation of light quality on physiological metabolism of Acanthopanax senticosus (Rupr.&Maxim.) Harms leaves. Northeast forestry University.
Fontana D., De Paula S., Torres A., De Souza V., Pascholati S., Schmidt D., et al. (2021). Endophytic fungi: Biological control and induced resistance to phytopathogens and abiotic stresses. Pathogens 10, 570. doi: 10.3390/pathogens10050570
Freschi L. and Mercier H. (2012). Connecting environmental stimuli and crassulacean acid metabolism expression: Phytohormones and other signaling molecules. Prog. Bot. 73, 231–255. doi: 10.1007/978-3-642-22746-2_9
Fukada K., Kajiya-Sawane M., Matsumoto Y., Hasegawa T., Fukaya Y., and Kajiya K. (2016). Antiedema effects of Siberian ginseng in humans and its molecular mechanism of lymphatic vascular function in vitro. Nutr. Res. 36, 689–695. doi: 10.1016/j.nutres.2016.02.012
Gai Z., Zhang M., Zhang P., Zhang J., Liu J., Cai L., et al. (2023). 2-oxoglutarate contributes to the effect of foliar nitrogen on enhancing drought tolerance during flowering and grain yield of soybean. Sci. Rep. 13, 7274. doi: 10.1038/s41598-023-34403-5
Gowtham H. G., Singh S. B., Shilpa N., Aiyaz M., Nataraj K., Udayashankar A. C., et al. (2022). Insight into Recent Progress and Perspectives in Improvement of Antioxidant Machinery upon PGPR Augmentation in Plants under Drought Stress: A Review. Antioxidants 11, 1763. doi: 10.3390/antiox11091763
Guan S., Ma J., Chu X., Gao Y., Zhang Y., Zhang X., et al. (2015). Effects of total flavones from Acanthopanax senticosus on L-type calcium channels, calcium transient and contractility in rat ventricular myocytes. Phytotherapy Res. 29, 533–539. doi: 10.1002/ptr.5278
Guo Y., Ren C., Yi J., Doughty R., and Zhao F. (2020). Contrasting responses of rhizosphere bacteria, fungi and arbuscular mycorrhizal fungi along an elevational gradient in a temperate montane forest of China. Front. Microbiol. 11. doi: 10.3389/fmicb.2020.02042
Gururani M. A., Upadhyaya C. P., Baskar V., Venkatesh J., Nookaraju A., and Park S. W. (2013). Plant growth-promoting rhizobacteria enhance abiotic stress tolerance in Solanum tuberosum through inducing changes in the expression of ROS-scavenging enzymes and improved photosynthetic performance. J. Plant Growth Regul. 32, 245–258. doi: 10.1007/s00344-012-9292-6
Hartmann M. and Six J. (2022). Soil structure and microbiome functions in agroecosystems. Nat. Rev. Earth Environ. 4, 4–18. doi: 10.1038/s43017-022-00366-w
Hoech K., Koopmann B., and von Tiedemann A. (2021). Lignin composition and timing of cell wall lignification are involved in brassica napus resistance to stem rot caused by Sclerotinia sclerotiorum. Phytopathology 111, 1438–1448. doi: 10.1094/PHYTO-09-20-0425-R
Ji C., Chen Z. Z., Kong X. H., Xin Z. W., Sun F. J., Xing J. H., et al. (2022). Biocontrol and plant growth promotion by combined Bacillus spp. inoculation affecting pathogen and AMF communities in the wheat rhizosphere at low salt stress conditions. Front. Plant Sci. 13. doi: 10.3389/FPLS.2022.1043171
Jiao Y., Niklas K. J., Wang L., Yu K., Li Y., and Shi P. (2022). Influence of leaf age on the scaling relationships of lamina mass vs. Area. Front. Plant Science. 13). doi: 10.3389/fpls.2022.860206
Lee D., Lee S. H., Cho N., Kim Y.-S., Song J., and Kim H. (2019). Effects of eleutherococcus extract mixture on endochondral bone formation in rats. IJMS 20, 1253. doi: 10.3390/ijms20051253
Lee D., Park J., Yoon J., Kim M.-Y., Choi H.-Y., and Kim H. (2012). Neuroprotective effects of Eleutherococcus senticosus bark on transient global cerebral ischemia in rats. J. Ethnopharmacology 139, 6–11. doi: 10.1016/j.jep.2011.05.024
Li T., Ferns K., Yan Z.-Q., Yin S.-Y., Kou J.-J., Li D., et al. (2016b). Acanthopanax senticosus: photochemistry and anticancer potential. Am. J. Chin. Med. 44, 1543–1558. doi: 10.1142/S0192415X16500865
Li J.-L., Li N., Lee H.-S., Xing S.-S., Qi S.-Z., Tuo Z.-D., et al. (2016a). Four new sesqui-lignans isolated from Acanthopanax senticosus and their diacylglycerol acyltransferase (DGAT) inhibitory activity. Fitoterapia 109, 185–189. doi: 10.1016/j.fitote.2016.01.009
Liu Y. L. (2023) in Effects of UV-A supplementary light treatment on physiological metabolism of Acanthopanax senticosus (Northeast Forestry University).
Liu S., Chen Y., Gu L., Li Y., Wang B., Hao J., et al. (2013). Purification of eleutherosides by macroporous resin and the active fractions of anti-inflammatory and antioxidant activity from Acanthopanax senticosus extract. Anal. Methods 5, 3732. doi: 10.1039/c3ay40164b
Liu H., Wang Z., Xu W., Zeng J., Li S., Li L., et al. (2020). Bacillus pumilus LZP02 promotes rice root growth by improving carbohydrate metabolism and phenylpropanoid biosynthesis. Mol. Plant Microbe Interact. 33, 1222–1231. doi: 10.1094/MPMI-04-20-0106-R
Liu Y., Zhang L., Li Q., Xue T., Qin F., and Xiong Z. (2024). Discovery of bioactive-chemical Q-markers of Acanthopanax sessiliflorus leaves: An integrated strategy of plant metabolomics, fingerprint and spectrum-efficacy relationship research. J. Chromatogr. B 1233, 124009. doi: 10.1016/j.jchromb.2024.124009
Mącik M., Gryta A., Sas-Paszt L., and Frąc M. (2020). The status of soil microbiome as affected by the application of phosphorus biofertilizer: fertilizer enriched with beneficial bacterial strains. Int. J. Mol. Sci. 21, 8003. doi: 10.3390/ijms21218003
Miljaković D., Marinković J., and Balešević-Tubić S. (2020). The significance of Bacillus spp. in disease suppression and growth promotion of field and vegetable crops. Microorganisms 8, 1037. doi: 10.3390/microorganisms8071037
Mohamed, Eid K. E., Abbas Mohamed H. H., Salem Ahmed A., Ahmed N., Ali M., et al. (2019). Use of plant growth promoting Rhizobacteria (PGPR) and mycorrhizae to improve the growth and nutrient utilization of common bean in a soil infected with white rot fungi. Ecotoxicol. Environ. Saf. 171, 539–548. doi: 10.1016/j.ecoenv.2018.12.100
Negi R., Sharma B., Kumar S., Chaubey K. K., Kaur T., Devi R., et al. (2024). Plant endophytes: unveiling hidden applications toward agro-environment sustainability. Folia Microbiol. (Praha) 69, 181–206. doi: 10.1007/s12223-023-01092-6
Neshat M. R., Abbasi A. R., Hosseinzadeh A. H., Sarikhani M. R., Dadashi Chavan D., and Rasoulnia A. R. (2022). Plant growth promoting bacteria (PGPR) induce antioxidant tolerance against salinity stress through biochemical and physiological mechanisms. Physiol. Mol. Biol. Plants 28, 347–361. doi: 10.1007/s12298-022-01128-0
Olivares-García C. A., Mata-Rosas M., Peña-Montes C., Quiroz-Figueroa F., Segura-Cabrera A., Shannon L. M., et al. (2020). Phenylpropanoids are connected to cell wall fortification and stress tolerance in avocado somatic embryogenesis. Int. J. Mol. Sci. 21, 5679. doi: 10.3390/ijms21165679
Rafique H. M., Khan M. Y., Asghar H. N., Ahmad Zahir Z., Nadeem S. M., Sohaib M., et al. (2023). Converging alfalfa (Medicago sativa L.) and petroleum hydrocarbon acclimated ACC-deaminase containing bacteria for phytoremediation of petroleum hydrocarbon contaminated soil. Int. J. Phytoremediation 25, 717–727. doi: 10.1080/15226514.2022.2104214
Riley D. and Barber S. A. (1970). Salt accumulation at the soybean (Glycine max (L.) Merr.) root-soil interface. Soil Sci. Soc. America J. 34, 154–155. doi: 10.2136/sssaj1970.03615995003400010042x
Semwal P., Misra S., Misra A., Kar S., Majhi B., Mishra S. K., et al. (2023). Endophytic Bacillus strains enhance biomass and bioactive metabolites of Gloriosa superba. Ind. Crops Products 204, 117296. doi: 10.1016/j.indcrop.2023.117296
Shao D., He Yi, Zhai Y., Yang X., Guo Z., Tan J., et al. (2025). Mechanisms of tomato growth promotion in three soils after applying Bacillus combinations. Soil and Tillage Research. Soil Tillage Res. 249, 106477. doi: 10.1016/j.still.2025.106477
Song H. Z. (2022) in Chemical Activity Determination of Acanthopanax senticosus, a Wild Medicinal Plant in the Ziwuling Reserve, and Research on Its Suitable Soil Environment (Yan’an University).
Tian L., Shi S., Ji L., Nasir F., Ma L., and Tian C. (2018). Effect of the biocontrol bacterium Bacillus amyloliquefaciens on the rhizosphere in ginseng plantings. Int. Microbiol. 21, 153–162. doi: 10.1007/s10123-018-0015-0
Tian S., Xu Y., Zhong Y., Qiao Y., Wang D., Wu L., et al. (2024). Exploring the organic acid secretion pathway and potassium solubilization ability of Pantoea vagans ZHS-1 for enhanced rice growth. Plants 13, 1945. doi: 10.3390/plants13141945
Todorova D., Aleksandrov V., Anev S., and Sergiev I. (2022). Photosynthesis alterations in wheat plants induced by herbicide, soil drought or flooding. Agronomy 12, 390. doi: 10.3390/agronomy12020390
Trivedi P., Leach J. E., Tringe S. G., Sa T., and Singh B. K. (2020). Plant-microbiome interactions: from community assembly to plant health. Nat. Rev. Microbiol. 18, 607–621. doi: 10.1038/s41579-020-0412-1
Wang Z. L. (2023) in Analysis of key metabolic pathways of flower anchor of oval leaves in response to altitude by combination of transcriptome and metabolome (Qinghai Normal University).
Xie Z., Chu Y., Zhang W., Lang D., and Zhang X. (2019). Bacillus pumilus alleviates drought stress and increases metabolite accumulation in Glycyrrhiza uralensis Fisch. Environ. Exp. Bot. 158, 99–106. doi: 10.1016/j.envexpbot.2018.11.021
Yang P., Zhao Z., Fan J., Liang Y., Bernier M. C., Gao Y., et al. (2023). Bacillus proteolyticus OSUB18 triggers induced systemic resistance against bacterial and fungal pathogens in Arabidopsis. Front. Plant Sci. 14. doi: 10.3389/fpls.2023.1078100
Yi W., Chen C., and Gan X. (2022). Active Metabolites From the Endophyte Paenibacillus polymyxa Y-1 of Dendrobium nobile for the Control of Rice Bacterial Diseases. Front. Chem. 10. doi: 10.3389/fchem.2022.879724
You Q., Ren Y., Li J., Zeng G., Luo X., Zheng C., et al. (2025). Ultrasound-Assisted Enzymatic Extraction of the Active Components from Acanthopanax sessiliflorus Stem and Bioactivity Comparison with Acanthopanax senticosus. Molecules 30, 397. doi: 10.3390/molecules30020397
Załuski D., Kuźniewski R., and Janeczko Z. (2018). HPTLC-profiling of eleutherosides, mechanism of antioxidative action of eleutheroside E1, the PAMPA test with LC/MS detection and the structure–activity relationship. Saudi J. Biol. Sci. 25, 520–528. doi: 10.1016/j.sjbs.2016.01.018
Zhang F., Dashti N., Hynes R. K., and Smith D. L. (1997). Plant growth-promoting rhizobacteria and soybean (Glycine max (L.) Merr.) growth and physiology at suboptimal root zone temperatures. Ann. Bot. 79, 243–249. doi: 10.1006/anbo.1996.0332
Zhang S. J. and Li X. L. (2021). The development and utilization of Acanthopanax senticosus. China Food Drug Adm. Mag. 5, 108–111.
Zhang H. J., Li X., White J. F., Wei X., He Y., and Li C. J. (2022). Epichloë endophyte improves ergot disease resistance of host (Achnatherum inebrians) by regulating leaf senescence and photosynthetic capacity. J. Plant Growth. Regul. 41, 808–817. doi: 10.1007/s00344-021-10340-3
Zhao S., An N., Zhang K., Li D., Wang L., and Wang Y. (2023b). Evaluation of drying kinetics, physical properties, bioactive compounds, antioxidant activity and microstructure of Acanthopanax sessiliflorus fruits dried by microwave-assisted hot air drying method. J. Food Eng. 357, 111642. doi: 10.1016/j.jfoodeng.2023.111642
Zhao Q., Wu Y.-N., Fan Q., Han Q.-Q., Paré P. W., Xu R., et al. (2016). Improved Growth and Metabolite Accumulation in Codonopsis pilosula (Franch.) Nannf. by Inoculation of Bacillus amyloliquefaciens GB03. J. Agric. Food Chem. 64, 8103–8108. doi: 10.1021/acs.jafc.6b03390
Zhao L., Xu Y., Huang X., Xi L., Song W., and Yang J. (2023a). Effects of two endophytic bacteria on SOD and CAT activities in soybean seedlings under salt stress in old yellow river basin in eastern Henan province, China. doi: 10.20944/preprints202310.1687.v1
Keywords: Acanthopanax senticosus, Bacillus fungorum, Bacillus proteolyticus, growth index, metabolism, photosynthetic characteristics
Citation: Qi J, Wei H, Zhang Y, Tang X, Zhong W, Tang Z, Liu Y and Li D (2025) Integrating growth, photosynthetic, and metabolomic analyses reveals how rhizobacteria affect Acanthopanax senticosus. Front. Agron. 7:1695649. doi: 10.3389/fagro.2025.1695649
Received: 30 August 2025; Accepted: 30 November 2025; Revised: 27 November 2025;
Published: 16 December 2025.
Edited by:
Shankar Ganapathi Shanmugam, Mississippi State University, United StatesReviewed by:
Qiongli Bao, Ministry of Agriculture and Rural Affairs, ChinaNeha Singh Chandel, GLA University, India
Copyright © 2025 Qi, Wei, Zhang, Tang, Zhong, Tang, Liu and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Ying Liu, YXJyaXZlMTAwQG5lZnUuZWR1LmNu; Dewen Li, bGR3QG5lZnUuZWR1LmNu
†These authors have contributed equally to this work