School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
MOE Key Laboratory on Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, 300350, Tianjin, China.
Microbiol Res. 2022 Mar;256:126943. doi: 10.1016/j.micres.2021.126943. Epub 2021 Dec 11.
Salinity stress is one of the most harmful abiotic stresses that inhibit crop growth and grain yield. In this study, a salt-tolerant bacterium was isolated from the soil of the rice rhizosphere and named Myroides sp. JIL321, based on the results of the phylogenetic tree analysis. The strain JIL321 tolerated up to 1, 283.37 mM of NaCl and exhibited positive plant growth-promoting traits, such as the production of indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Therefore, the effects of JIL321 on rice (Oryza sativa L.) under salinity stress were determined. The inoculation of strain JIL321 significantly increased the chlorophyll content and the accumulation of osmotic adjustment substances, such as proline and soluble sugars, in rice expose to salt stress. Additionally, strain JIL321 inoculation significantly enhanced the activities of some enzymes commonly found in soil, such as urease, invertase and catalase. Moreover, the production of hydrogen sulfide (HS), a pivotal signaling molecule, was also induced in rice by salt stress. Treatment with sodium hydrogen sulfide (NaHS, HS donor) improved salt stress tolerance of the rice, while treatment with hypotaurine (HT, HS scavenger) significantly suppressed it. Interestingly, NaHS treatment also improved the production of IAA and ACC deaminase in strain JIL321 under 0 mM and 150 mM salt concentrations. The combined treatment of JIL321 and NaHS could further improve the growth of salt-stressed rice seedlings, most likely due to the interaction effect between HS and strain JIL321. To our knowledge, this study is the first to demonstrate that the combined use of HS and plant growth-promoting bacteria could alleviate the adverse effects of salt stress on rice plants, and further verifies the novel role of HS as a signaling molecule that enhance the tolerance of plant to abiotic stresses.
盐胁迫是抑制作物生长和籽粒产量的最有害非生物胁迫之一。在这项研究中，根据系统发育树分析的结果，从水稻根际土壤中分离到一株耐盐细菌，并将其命名为 Myroides sp. JIL321。菌株 JIL321 可耐受高达 1283.37mM 的 NaCl，并表现出积极的植物促生特性，如产生吲哚乙酸（IAA）和 1-氨基环丙烷-1-羧酸（ACC）脱氨酶。因此，确定了 JIL321 菌株在盐胁迫下对水稻（Oryza sativa L.）的影响。接种该菌株可显著提高盐胁迫下水稻的叶绿素含量和渗透调节物质（如脯氨酸和可溶性糖）的积累。此外，菌株 JIL321 的接种显著增强了土壤中常见的一些酶的活性，如脲酶、转化酶和过氧化氢酶。此外，盐胁迫还诱导水稻产生关键信号分子硫化氢（HS）。硫化氢供体（NaHS）处理可提高水稻的耐盐性，而 HS 清除剂（HT）处理则显著抑制其耐盐性。有趣的是，NaHS 处理还可提高 JIL321 菌株在 0mM 和 150mM 盐浓度下 IAA 和 ACC 脱氨酶的产生。JIL321 和 NaHS 的联合处理可进一步改善盐胁迫下水稻幼苗的生长，这可能是由于 HS 和 JIL321 菌株之间的相互作用。据我们所知，这项研究首次证明了 HS 和植物促生细菌的联合使用可以减轻盐胁迫对水稻植株的不利影响，并进一步验证了 HS 作为一种信号分子增强植物对非生物胁迫耐受性的新作用。
