School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Microbiol Res. 2023 Jan;266:127225. doi: 10.1016/j.micres.2022.127225. Epub 2022 Oct 9.
Salt stress poses a global challenge for agriculture, crop growth, and food production. In this study, a strain of rhizobacteria with both plant growth-promoting (PGP) traits and salt tolerance was isolated. The strain was identified as Bacillus pumilus via 16 S rDNA sequencing and was named B. pumilus JIZ13. This strain had the potential to solubilize phosphates and produce 1-aminocyclopropane-1-carboxylic acid deaminase, siderophores, and indole-3-acetic acid. After 35 days of salt stress exposure, the root length, plant height, dry weight, fresh weight, and relative water content of rice plants inoculated with strain JIZ13 were significantly higher than those without inoculation. Interestingly, the PGP properties of strain JIZ13 were significantly improved by the exogenous addition of gamma-aminobutyric acid (GABA). Moreover, GABA also enhanced the growth and development of rice plants under salt stress by providing substrates for the tricarboxylic acid cycle. Furthermore, the synergistic roles of GABA and strain JIZ13 in mitigating the damage caused by salt stress in rice plants was investigated. The results showed that the co-application of GABA and JIZ13 significantly increased photosynthetic efficiency, chlorophyll accumulation, antioxidant levels, levels of osmotic adjustment substances, and biomass of rice under salinity stress. In addition, the activities of urease, protease, invertase, and catalase enzymes in soil significantly improved under the combination of strain JIZ13 and GABA and increased by 39.65%, 36.88%, 70.21%, and 65.23%, respectively, compared to those without rhizobacterial and GABA additions. The enhancement of these four soil enzyme activities might thus improve soil quality and increase root elongation and biomass in rice plants. The results of this study provide the first evidence that PGP-rhizobacterial strain JIZ13 along with GABA can attenuate the negative effects of salt stress in rice plants.
盐胁迫对农业、作物生长和粮食生产构成了全球性挑战。本研究从土壤中分离得到一株具有促生和耐盐特性的根际细菌。通过 16S rDNA 测序鉴定该菌株为解淀粉芽孢杆菌（Bacillus pumilus），并命名为 B. pumilus JIZ13。该菌株具有溶磷能力，能产 1-氨基环丙烷-1-羧酸脱氨酶、铁载体和吲哚乙酸。经过 35 天盐胁迫处理，接种 JIZ13 的水稻根长、株高、干重、鲜重和相对含水量均显著高于未接种的对照。有趣的是，外源性添加γ-氨基丁酸（GABA）可显著提高 JIZ13 的促生特性。此外，GABA 还通过为三羧酸循环提供底物来增强水稻在盐胁迫下的生长发育。进一步研究了 GABA 和 JIZ13 对缓解水稻盐胁迫损伤的协同作用。结果表明，GABA 和 JIZ13 协同作用可显著提高盐胁迫下水稻的光合效率、叶绿素积累、抗氧化水平、渗透调节物质水平和生物量。此外，在 JIZ13 和 GABA 组合处理下，土壤中脲酶、蛋白酶、转化酶和过氧化氢酶的活性分别显著提高了 39.65%、36.88%、70.21%和 65.23%，而未添加根际细菌和 GABA 的土壤酶活性没有明显变化。因此，这四种土壤酶活性的增强可能会改善土壤质量，促进水稻根系伸长和生物量增加。本研究首次证明，促生根际细菌 JIZ13 与 GABA 联合使用可以减轻盐胁迫对水稻的负面影响。
