Salt stress is a serious environmental challenge that hinders crop growth and yield. Plant growth-promoting rhizobacteria (PGPR) can successfully and environmentally friendly boost plant development in saline soils. In this study, a halotolerant sp. NTN6 was isolated from the rhizosphere soil of halophyte and its plant growth-promoting properties were determined. NTN6 inoculation significantly promoted seed germination and seedling growth in maize under salt stress. Shoot height, stem thickness, root fresh weight, shoot fresh weight, root dry weight, and shoot dry weight of salt-stressed seedlings increased by 36.3%, 32.5%, 146.4%, 193.6%, 25.0%, and 109.6%, respectively, after inoculation with NTN6. NTN6-mediated maize salt tolerance was revealed via transcriptomic, physiological, and biochemical analyses. Under salt stress, NTN6 regulated the transcript levels of genes related to chlorophyll synthesis, photosynthesis apparatus, and carbon assimilation pathways, and thus increasing chlorophyll content, Fv/Fm, and net photosynthetic rate; NTN6 reduced the content of O, HO, and MDA by regulating the transcripts and activities of antioxidant enzymes; NTN6 affected the transcriptional response of genes involved in ABA synthesis and signaling to salt stress and reduced ABA level. Finally, NTN6 boosted photosynthetic capacity in salt-stressed maize by modulating photochemical activity, C pathway and Calvin cycle as well as mitigating reactive oxygen species damage to the photosystem reaction center. This study first investigated the mechanism of sp.-induced salt tolerance in maize and these findings demonstrate the valuable contribution of halotolerant PGPR strain from halophytes in improving salinity tolerance in non-halophytic crops.

中文翻译：

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综合生理、生化和转录组分析揭示了耐盐沙雷氏菌诱导的耐盐机制。玉米中的NTN6

盐胁迫是阻碍作物生长和产量的严重环境挑战。植物促生根际细菌（PGPR）可以成功且环保地促进盐渍土壤中的植物发育。在这项研究中，耐盐菌。从盐生植物根际土壤中分离出NTN6，并测定其促进植物生长的特性。接种NTN6显着促进盐胁迫下玉米种子萌发和幼苗生长。盐胁迫幼苗的芽高、茎粗、根鲜重、芽鲜重、根干重和芽干重分别增加了36.3%、32.5%、146.4%、193.6%、25.0%和109.6%。接种NTN6后。通过转录组学、生理学和生化分析揭示了 NTN6 介导的玉米耐盐性。盐胁迫下，NTN6调节叶绿素合成、光合机构和碳同化途径相关基因的转录水平，从而提高叶绿素含量、Fv/Fm和净光合速​​率； NTN6通过调节抗氧化酶的转录和活性，降低O、H2O和MDA的含量； NTN6 影响参与 ABA 合成和盐胁迫信号转导的基因的转录反应，并降低 ABA 水平。最后，NTN6 通过调节光化学活性、C 途径和卡尔文循环以及减轻活性氧对光系统反应中心的损害来提高盐胁迫玉米的光合能力。本研究首先研究了 sp. 诱导玉米耐盐性的机制，这些发现证明了来自盐生植物的耐盐 PGPR 菌株在提高非盐生作物的耐盐性方面的宝贵贡献。