ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Abiotic Stress
Volume 16 - 2025 | doi: 10.3389/fpls.2025.1692304
This article is part of the Research TopicExploring Cold Tolerance and Stress in PlantsView all articles
Mycorrhizal Helper Bacteria Further Promote Mycorrhizal Fungi to Improve Cold Tolerance in Rice Seedlings: Evidence from Oxidative Stress, Osmoregulation, Photosynthesis, and Related Genes in Rice
Provisionally accepted
- 1Heilongjiang University, Harbin, China
- 2Heilongjiang Academy of Agricultural Sciences, Harbin, China
- 3Heilongjiang Vocational and Technical College of Architecture, Harbin, China
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Abstracts: Cold stress critically threatens rice productivity, necessitating innovative strategies to enhance seedling resilience. While arbuscular mycorrhizal fungi (AMF) and associated bacteria synergistically improve plant stress tolerance, their collaborative mechanisms in rice cold adaptation remain underexplored. Here, we developed a composite inoculant combining Rhizophagus intraradices (Ri) with Agrobacterium rhizogenes (Ar) and Bacillus subtilis (Bs) to investigate their synergistic effects under graded cold stress (25–4°C). The Ri+Ar+Bs (RAB) consortium elevated mycorrhizal colonization by 17% (reaching 87.5%) and synergistically promoted plant growth, increasing height and root length by 9.56% and 43.7%, respectively, under 4°C stress compared to Ri alone. RAB enhanced antioxidant capacity (24.9% higher SOD activity, 12.37-fold CAT activity) and proline accumulation (78.4%), reducing malondialdehyde (43.7%) and electrolyte leakage (13.64%). Hormonal equilibrium was maintained via upregulated indole-3-acetic acid and gibberellic acid levels. Photosynthetic performance improved significantly (11.29% higher net rate at 4°C), supported by activation of OsHBP1b and CBF1. Concurrently, RAB upregulated cold-tolerance genes (LTG5RT, OsDREB1A), with functional specialization observed: Ar amplified Ri-mediated height improvement and gene expression, while Bs enhanced root development and photosynthetic efficiency. These findings advance microbial consortia design for climate-resilient agriculture, offering actionable strategies to safeguard rice productivity under extreme cold.
Keywords: AMF, rice, cold stress, physiological response, Mycorrhizal helper bacteria
Received: 25 Aug 2025; Accepted: 28 Sep 2025.
Copyright: © 2025 Shi, Liu, He, Zhu, Li, Ding, Zhang, Tianle and Song. 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) or licensor 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: Fuqiang Song, 0431sfq@163.com
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