Zheng Yanfen, Cao Xuwen, Zhou Yanan, Ma Siqi, Wang Youqiang, Li Zhe, Zhao Donglin, Yang Yanzhe, Zhang Han, Meng Chen, Xie Zhihong, Sui Xiaona, Xu Kangwen, Li Yiqiang, Zhang Cheng-Sheng
Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
Institute of Marine Science and Technology, Shandong University, Qingdao, 266200, China.
Nat Commun. 2024 Apr 25;15(1):3520. doi: 10.1038/s41467-024-47773-9.
The root-associated microbiota plays an important role in the response to environmental stress. However, the underlying mechanisms controlling the interaction between salt-stressed plants and microbiota are poorly understood. Here, by focusing on a salt-tolerant plant wild soybean (Glycine soja), we demonstrate that highly conserved microbes dominated by Pseudomonas are enriched in the root and rhizosphere microbiota of salt-stressed plant. Two corresponding Pseudomonas isolates are confirmed to enhance the salt tolerance of wild soybean. Shotgun metagenomic and metatranscriptomic sequencing reveal that motility-associated genes, mainly chemotaxis and flagellar assembly, are significantly enriched and expressed in salt-treated samples. We further find that roots of salt stressed plants secreted purines, especially xanthine, which induce motility of the Pseudomonas isolates. Moreover, exogenous application for xanthine to non-stressed plants results in Pseudomonas enrichment, reproducing the microbiota shift in salt-stressed root. Finally, Pseudomonas mutant analysis shows that the motility related gene cheW is required for chemotaxis toward xanthine and for enhancing plant salt tolerance. Our study proposes that wild soybean recruits beneficial Pseudomonas species by exudating key metabolites (i.e., purine) against salt stress.
根系相关微生物群在植物应对环境胁迫中发挥着重要作用。然而，目前对盐胁迫植物与微生物群之间相互作用的潜在机制仍知之甚少。在此，我们以耐盐野生大豆（Glycine soja）为研究对象，发现以假单胞菌为主的高度保守微生物在盐胁迫植物的根和根际微生物群中富集。两种相应的假单胞菌菌株被证实可提高野生大豆的耐盐性。鸟枪法宏基因组和宏转录组测序表明，与运动性相关的基因，主要是趋化性和鞭毛组装相关基因，在盐处理样本中显著富集并表达。我们进一步发现，盐胁迫植物的根分泌嘌呤，尤其是黄嘌呤，可诱导假单胞菌菌株的运动性。此外，向未受胁迫的植物外源施加黄嘌呤会导致假单胞菌富集，重现盐胁迫根中微生物群的变化。最后，假单胞菌突变体分析表明，运动相关基因cheW是对黄嘌呤趋化作用和增强植物耐盐性所必需的。我们的研究表明，野生大豆通过分泌关键代谢物（即嘌呤）来招募有益假单胞菌以应对盐胁迫。
