CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India.
Plant Physiol Biochem. 2013 May;66:1-9. doi: 10.1016/j.plaphy.2013.01.020. Epub 2013 Feb 14.
Growth and productivity of rice and soil inhabiting microbial population is negatively affected by soil salinity. However, some salt resistant, rhizosphere competent bacteria improve plant health in saline stress. Present study evaluated the effect of salt tolerant Bacillus amyloliquefaciens NBRISN13 (SN13) inoculation on rice plants in hydroponic and soil conditions exposed to salinity. SN13 increased plant growth and salt tolerance (NaCl 200 mM) and expression of at least 14 genes under hydroponic and soil conditions in rice. Among these 14 genes 4 (NADP-Me2, EREBP, SOSI, BADH and SERK1) were up-regulated and 2 (GIG and SAPK4) repressed under salt stress in hydroponic condition. In greenhouse experiment, salt stress resulted in accumulation of MAPK5 and down-regulation of the remaining 13 transcripts was observed. SN13 treatment, with or without salt gave similar expression for all tested genes as compared to control. Salt stress caused changes in the microbial diversity of the rice rhizosphere and stimulated population of betaine-, sucrose-, trehalose-, and glutamine-utilizing bacteria in salt-treated rice rhizosphere (SN13 + salt). The observations imply that SN13 confers salt tolerance in rice by modulating differential transcription in a set of at least 14 genes. Stimulation of osmoprotectant utilizing microbial population as a mechanism of inducing salt tolerance in rice is reported for the first time in this study to the best of our knowledge.
土壤盐分可负向影响水稻和土壤微生物种群的生长和生产力。然而，一些耐盐、根际定殖能力强的细菌可在盐胁迫下改善植物健康状况。本研究评估了耐盐解淀粉芽孢杆菌 NBRISN13（SN13）在水培和土壤条件下接种盐胁迫水稻植株的效果。SN13 可在水培和土壤条件下提高水稻的生长和耐盐性（NaCl 200 mM），并至少上调 14 个基因的表达。在这 14 个基因中，有 4 个（NADP-Me2、EREBP、SOSI 和 BADH 和 SERK1）在水培条件下受到盐胁迫而上调，有 2 个（GIG 和 SAPK4）受到抑制。在温室试验中，盐胁迫导致 MAPK5 积累，其余 13 个转录本的表达下调。与对照相比，SN13 处理（无论是否加盐）对所有测试基因的表达均相似。盐胁迫改变了水稻根际微生物的多样性，并刺激了甜菜碱、蔗糖、海藻糖和谷氨酰胺利用菌在盐处理水稻根际（SN13+盐）中的种群。这些观察结果表明，SN13 通过调节至少 14 个基因的差异转录赋予水稻耐盐性。据我们所知，本研究首次报道了通过刺激利用渗透调节剂的微生物种群来诱导水稻耐盐性的机制。
