Ma Xiaojing, Ouyang Zhaopeng, Luo Hengbin, Shang Wenkai, Ma Haohao, Zhu Mengmeng, Dong Han, Guo Zhixin, Dong Xiaoxing, Piao Fengzhi, Shen Shunshan, Li Xinzheng, Wang Yong, Zhang Tao
College of Horticulture, Henan Agricultural University, Zhengzhou, China.
College of Plant Protection, Henan Agricultural University, Zhengzhou, China.
Microbiol Res. 2025 Jul;296:128143. doi: 10.1016/j.micres.2025.128143. Epub 2025 Mar 17.
The application of plant growth-promoting rhizobacteria (PGRP) is a promising and innovative strategy for alleviating salt stress in plants. However, the mechanism underlying PGRP-mediated alleviation of salt stress is currently unclear. In this study, we observed that the tomatoes inoculated with Bacillus velezensis HR6-1 exhibited better growth indicators and photosynthesis-related parameters than non-colonized tomatoes under salt stress. Physiological analysis showed that tomatoes inoculated with HR6-1 exhibited better Na/K balance and lower ROS accumulation and oxidative damage, and higher activities of antioxidant enzymes compared with non-colonized tomatoes under salt stress. Transcriptome analysis revealed that under salt stress, HR6-1 treatment improved the expression of various transcription factors (especially WRKYs and ERFs) and many genes related to plant hormone signal transduction, the MAPK signaling pathway, the salt overly sensitive pathway, and detoxification in tomatoes. Moreover, HR6-1 inoculation increased the content of cZ- and tZ-type cytokinins in salt-treated tomato seedlings, which was consistent with the high expression of several cytokinin synthesis genes. Treatment with a cytokinin synthesis inhibitor prevented HR6-1-mediated improvement in salt tolerance in tomato seedlings, implying that HR6-1 stimulates cytokinin synthesis to enhance tomato resistance to salt stress. Our findings identify a potential biostimulant for improving tomato growth under salt stress and deepen our understanding of PGPR-mediated salinity alleviation in tomato seedlings.
植物促生根际细菌（PGRP）的应用是缓解植物盐胁迫的一种有前景且创新的策略。然而，目前PGRP介导缓解盐胁迫的机制尚不清楚。在本研究中，我们观察到，在盐胁迫下，接种解淀粉芽孢杆菌HR6-1的番茄比未定殖的番茄表现出更好的生长指标和光合相关参数。生理分析表明，与盐胁迫下未定殖的番茄相比，接种HR6-1的番茄表现出更好的钠/钾平衡、更低的活性氧积累和氧化损伤，以及更高的抗氧化酶活性。转录组分析显示，在盐胁迫下，HR6-1处理提高了番茄中各种转录因子（尤其是WRKYs和ERFs）以及许多与植物激素信号转导、MAPK信号通路、盐过敏途径和解毒相关基因的表达。此外，接种HR6-1增加了盐处理番茄幼苗中顺式玉米素和反式玉米素型细胞分裂素的含量，这与几个细胞分裂素合成基因的高表达一致。用细胞分裂素合成抑制剂处理可阻止HR6-1介导的番茄幼苗耐盐性提高，这意味着HR6-1刺激细胞分裂素合成以增强番茄对盐胁迫的抗性。我们的研究结果确定了一种在盐胁迫下改善番茄生长的潜在生物刺激剂，并加深了我们对PGPR介导的番茄幼苗盐度缓解的理解。
