Key message

Overexpression of Bacillus amyloliquefaciens SN13-responsive OsNAM gene in Arabidopsis reveals its important role in beneficial plant and plant growth promoting rhizobacteria interaction by conferring stress tolerance and phytohormone modulation.

Abstract

Salinity is one of the major constraints that affect crop development and yield. Plants respond and adapt to salt stress via complex mechanisms that involve morpho-physiological, biochemical, and molecular changes. The expression of numerous genes is known to alter during various abiotic stresses and impart stress tolerance. Recently, some known rhizospheric microbes have also been used to mitigate the effects of abiotic stresses; however, the molecular basis of such interactions remains elusive. Therefore, the present investigation was aimed to elucidate the plant growth-promoting rhizobacteria (PGPR; Bacillus amyloliquefaciens-SN13) -induced crosstalk among salinity and phytohormones in OsNAM-overexpressed Arabidopsis plants. Transgenic plants showed increased germination percentage compared to wild-type (WT) seeds under 100 mM of NaCl. Phenotypic data showed increased root length, rosette diameter, leaf size, and biomass in transgenics than WT plants. Transgenic plants can also better maintain membrane integrity and osmolyte concentration under salinity as compared to WT. Further, gene expression analysis of AP2/ERF, GST, ERD4, and ARF2 genes showed differential expression and their positive modulation in transgenic Arabidopsis exposed to salt stress in the presence of SN13 as compared to uninoculated WT. Modulation in IAA, ABA, and GA content in inoculated plants showed the more pronounced positive effects of SN13 on transgenic plants that supported our findings on Arabidopsis–SN13 interaction. Overall, the study concludes that SN13 positively modulated expression of stress-responsive genes under salinity and alter phytohormones levels in OsNAM-overexpressed plants suggesting its extensive role in cross-talk among salinity and phytohormones in response to PGPR.

中文翻译：

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OsNAM 基因通过非生物胁迫和植物激素串扰在转基因拟南芥根际根际细菌相互作用中发挥重要作用

关键信息

在拟南芥中过表达解淀粉芽孢杆菌SN13 响应性 OsNAM基因揭示了其通过赋予胁迫耐受性和植物激素调节在促进植物和植物生长促进根际细菌相互作用中的重要作用。

抽象的

盐度是影响作物发育和产量的主要制约因素之一。植物通过涉及形态生理、生化和分子变化的复杂机制来响应和适应盐胁迫。已知许多基因的表达在各种非生物胁迫期间会发生改变并赋予胁迫耐受性。最近，一些已知的根际微生物也被用来减轻非生物胁迫的影响。然而，这种相互作用的分子基础仍然难以捉摸。因此，本研究旨在阐明植物生长促进根际细菌 (PGPR; Bacillus amyloliquefaciens -SN13) 在OsNAM过表达的拟南芥中诱导的盐度和植物激素之间的串扰植物。在 100 mM NaCl 下，与野生型 (WT) 种子相比，转基因植物的发芽率增加。表型数据显示转基因植物的根长、莲座直径、叶大小和生物量比野生型植物增加。与 WT 相比，转基因植物在盐度下也可以更好地保持膜完整性和渗透物浓度。此外，AP2/ERF、GST、ERD4和ARF2基因的基因表达分析显示，与未接种的 WT 相比，在 SN13 存在下暴露于盐胁迫的转基因拟南芥中存在差异表达及其正调节。接种植物中 IAA、ABA 和 GA 含量的调节显示了 SN13 对转基因植物的更明显的积极影响，这支持了我们在拟南芥-SN13 相互作用。总体而言，该研究得出结论，SN13 在盐度下正向调节胁迫响应基因的表达，并改变OsNAM过表达的植物中的植物激素水平，这表明它在盐度和植物激素对 PGPR 的反应中发挥广泛作用。