Hunan Province Key Laboratory of Crop Sterile Germplasm Resource Innovation and Application, College of Life Science, Hunan Normal University, Changsha, 410081, China.
College of Chemistry and Chemical Engineering, Jishou University, Hunan, 416000, China.
BMC Plant Biol. 2023 Nov 9;23(1):553. doi: 10.1186/s12870-023-04533-z.
Rice (Oryza sativa L.) is one of the most widely cultivated grain crops in the world that meets the caloric needs of more than half the world's population. Salt stress seriously affects rice production and threatens food security. Therefore, mining salt tolerance genes in salt-tolerant germplasm and elucidating their molecular mechanisms in rice are necessary for the breeding of salt tolerant cultivars.
In this study, a salt stress-responsive jacalin-related lectin (JRL) family gene, OsJRL45, was identified in the salt-tolerant rice variety 'sea rice 86' (SR86). OsJRL45 showed high expression level in leaves, and the corresponding protein mainly localized to the endoplasmic reticulum. The knockout mutant and overexpression lines of OsJRL45 revealed that OsJRL45 positively regulates the salt tolerance of rice plants at all growth stages. Compared with the wild type (WT), the OsJRL45 overexpression lines showed greater salt tolerance at the reproductive stage, and significantly higher seed setting rate and 1,000-grain weight. Moreover, OsJRL45 expression significantly improved the salt-resistant ability and yield of a salt-sensitive indica cultivar, L6-23. Furthermore, OsJRL45 enhanced the antioxidant capacity of rice plants and facilitated the maintenance of Na-K homeostasis under salt stress conditions. Five proteins associated with OsJRL45 were screened by transcriptome and interaction network analysis, of which one, the transmembrane transporter Os10g0210500 affects the salt tolerance of rice by regulating ion transport-, salt stress-, and hormone-responsive proteins.
The OsJRL45 gene isolated from SR86 positively regulated the salt tolerance of rice plants at all growth stages, and significantly increased the yield of salt-sensitive rice cultivar under NaCl treatment. OsJRL45 increased the activity of antioxidant enzyme of rice and regulated Na/K dynamic equilibrium under salinity conditions. Our data suggest that OsJRL45 may improve the salt tolerance of rice by mediating the expression of ion transport-, salt stress response-, and hormone response-related genes.
水稻（Oryza sativa L.）是世界上种植最广泛的粮食作物之一，满足了全球一半以上人口的热量需求。盐胁迫严重影响水稻生产，威胁粮食安全。因此，挖掘耐盐种质资源中的耐盐基因并阐明其在水稻中的分子机制，对于培育耐盐品种是必要的。
本研究在耐盐水稻品种‘海稻 86’（SR86）中鉴定到一个盐胁迫响应的豆科凝集素（JRL）家族基因 OsJRL45。OsJRL45 在叶片中表达水平较高，相应的蛋白主要定位于内质网。OsJRL45 的敲除突变体和过表达系表明，OsJRL45 正向调控水稻植株在所有生长阶段的耐盐性。与野生型（WT）相比，OsJRL45 过表达系在生殖期表现出更强的耐盐性，结实率和千粒重显著提高。此外，OsJRL45 表达显著提高了敏感籼稻品种 L6-23 的耐盐能力和产量。此外，OsJRL45 增强了水稻植株的抗氧化能力，并在盐胁迫条件下有助于维持 Na-K 平衡。通过转录组和互作网络分析筛选到与 OsJRL45 相关的 5 个蛋白，其中一个跨膜转运蛋白 Os10g0210500 通过调节离子转运、盐胁迫和激素响应蛋白影响水稻的耐盐性。
从 SR86 中分离的 OsJRL45 基因正向调控水稻植株在所有生长阶段的耐盐性，在 NaCl 处理下显著提高了敏感水稻品种的产量。OsJRL45 在盐胁迫条件下增加了水稻抗氧化酶的活性，并调节了 Na/K 动态平衡。我们的数据表明，OsJRL45 可能通过调节离子转运、盐胁迫响应和激素响应相关基因的表达来提高水稻的耐盐性。
