AUTHOR=Ren Wenda , Guo Yun , Han Xu , Sun Yan , Li Qing , Wu Bangli , Xia Tingting , Shen Kaiping , Wu Pan , He Yuejun 

TITLE=Indigenous Microorganisms Offset Arbuscular Mycorrhizal Fungi-Induced Plant Growth and Nutrient Acquisition Through Negatively Modulating the Genes of Phosphorus Transport and Nitrogen Assimilation

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.880181

DOI=10.3389/fpls.2022.880181

ISSN=1664-462X

ABSTRACT=AM fungi that promote plant growth and nutrient acquisition are essential for nutrient-deficient karst areas, while it inevitably regulate host plants jointly with indigenous microorganisms in natural soil. However, how indigenous microorganisms regulate AM-induced benefits on plant growth and nutrient acquisition remains unclear. In this study, the Bidens tripartita as the common plant species in karst region was cultivated into three soil substrates treated by AM fungi inoculation (AMF), AM fungi inoculation combining with indigenous microorganisms (AMI) and the control without AM fungi and indigenous microorganisms (CK). The plants bio mass and concentration of N and P were measured and the transcriptomic analysis was carried out using root tissues. The results showed that AM fungi significantly enhanced the plant biomass, nitrogen, and phosphorus accumulation with the reduction of plants N/P ratio； however， the indigenous microorganisms offset the AM-induced benefits in biomass and N and P acquisition. Additionally, there are 819 genes in DEGs of AMF vs. AMI ∩ AMF vs. CK, meaning that AM fungi induced these genes which were simultaneously regulated by indigenous microorganisms. Furthermore, the enrichment analysis suggested that these genes were significantly associated with the metabolic processes of organophosphate, P, sulfur, N and arginine biosynthesis. 34 and 17 of DEGs were respectively related to P and N metabolism. Moreover, the indigenous microorganisms significantly down-regulated these DEGs, especially those encoding the PHO1 phosphorus transporters and the glnA, GDH2 and urease as key enzymes in N assimilation; however, the indigenous microorganisms significantly up-regulated genes encoding PHO84 inducing cellular response to phosphate starvation. These regulations indicated that indigenous microorganisms restrained the N and P metabolism induced by AM fungi. In conclusion, we suggested that indigenous microorganisms offset nutrient benefits of AM fungi for host plants through regulating these genes related to phosphorus transport and nitrogen assimilation.