National Institute for Genomics and Advanced Biotechnology (NIGAB), NARC, Park Road, Islamabad, 45500, Pakistan.
Department of Biochemistry, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia.
Mol Biol Rep. 2023 Dec 18;51(1):22. doi: 10.1007/s11033-023-08998-x.
Salinity is one of the main abiotic factors that restrict plant growth, physiology, and crop productivity is salt stress. About 33% of the total irrigated land suffers from severe salinity because of intensive underground water extraction and irrigation with brackish water. Thus, it is important to understand the genetic mechanism and identify the novel genes involved in salt tolerance for the development of climate-resilient rice cultivars.
In this study, two rice genotypes with varying tolerance to salt stress were used to investigate the differential expressed genes and molecular pathways to adapt under saline soil by comparative RNA sequencing at 42 days of the seedling stage. Salt-susceptible (S3) and -tolerant (S13) genotypes revealed 3982 and 3463 differentially expressed genes in S3 and S13 genotypes. The up-regulated genes in both genotypes were substantially enriched in different metabolic processes and binding activities. Biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, and plant signal transduction mechanisms were highly enriched. Salt-susceptible and -tolerant genotypes shared the same salt adaptability mechanism with no significant quantitative differences at the transcriptome level. Moreover, bHLH, ERF, NAC, WRKY, and MYB transcription factors were substantially up-regulated under salt stress. 391 out of 1806 identified novel genes involved in signal transduction mechanisms. Expression profiling of six novel genes further validated the findings from RNA-seq data.
These findings suggest that the differentially expressed genes and molecular mechanisms involved in salt stress adaptation are conserved in both salt-susceptible and salt-tolerant rice genotypes. Further molecular characterization of novel genes will help to understand the genetic mechanism underlying salt tolerance in rice.
盐度是限制植物生长、生理和作物生产力的主要非生物因素之一，盐胁迫是植物面临的主要逆境胁迫之一。由于地下水的大量开采和咸水灌溉，约有 33%的灌溉土地受到严重盐渍化的影响。因此，了解耐盐的遗传机制和鉴定参与耐盐的新基因对于培育耐盐水稻品种具有重要意义。
本研究利用两个耐盐性不同的水稻基因型，在幼苗期 42 天，通过比较 RNA 测序研究了适应盐渍土壤的差异表达基因和分子途径。盐敏感型（S3）和耐盐型（S13）基因型在 S3 和 S13 基因型中分别显示出 3982 和 3463 个差异表达基因。两个基因型中上调的基因在不同的代谢过程和结合活性中显著富集。次生代谢物的生物合成、苯丙烷生物合成和植物信号转导机制高度富集。盐敏感型和耐盐型基因型具有相同的盐适应机制，在转录组水平上没有显著的数量差异。此外，bHLH、ERF、NAC、WRKY 和 MYB 转录因子在盐胁迫下显著上调。在 1806 个鉴定的新基因中，有 391 个参与信号转导机制。六个新基因的表达谱分析进一步验证了 RNA-seq 数据的结果。
这些发现表明，参与盐胁迫适应的差异表达基因和分子机制在盐敏感型和耐盐型水稻基因型中是保守的。对新基因的进一步分子特征分析将有助于了解水稻耐盐的遗传机制。
