National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China.
Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Physiol Plant. 2021 Dec;173(4):2026-2040. doi: 10.1111/ppl.13549. Epub 2021 Sep 17.
Salinity is one of the major abiotic constraints affecting the growth and yield of plants including soybean. In this context, the previous studies have documented the role of the mitogen-activated protein kinase (MAPK) cascade in the regulation of salt signaling in model plants. However, there is not a systematic analysis of salt-related MAPKs in soybean. Hence, in this study, we identified a total of 32 GmMAPKs via., genome-wide reanalysis of the MAPK family using the soybean genome v4.0. Based on the transcriptome datasets in the public database, we observed that GmMAPKs are induced by different abiotic stresses, especially salt stress. Furthermore, based on the candidate gene association mapping and haplotype analysis of the GmMAPKs, we identified a salt-related MAPK member, GmMMK1. GmMMK1 possesses significant sequence variations, which affect salt tolerance in soybean at the germination stage. Besides, the overexpression of the GmMMK1 in soybean hairy roots has a significant negative effect on the root growth, leading to increased sensitivity of the GmMMK1-OE plants to salt stress. Moreover, the heterologous expression of the GmMMK1 in Arabidopsis has been also observed to have a negative effect on the germination and root growth under salt stress. The transcriptome analysis and yeast two-hybrid screening showed that hormone signaling and the homeostasis of reactive oxygen species are involved in the GmMMK1 regulation network. In conclusion, the results of this work demonstrated that GmMMK1 is an important negative regulator of the salt stress response, and provides better insights for understanding the role of the MAPKs in soybean salt signaling.
盐度是影响包括大豆在内的植物生长和产量的主要非生物限制因素之一。在这方面，先前的研究已经记录了丝裂原活化蛋白激酶 (MAPK) 级联在模式植物中盐信号转导调节中的作用。然而，大豆中与盐相关的 MAPK 并没有系统的分析。因此，在这项研究中，我们通过大豆基因组 v4.0 对 MAPK 家族进行全基因组重新分析，共鉴定出 32 个 GmMAPKs。基于公共数据库中的转录组数据集，我们观察到 GmMAPKs 受不同非生物胁迫的诱导，尤其是盐胁迫。此外，基于候选基因关联图谱和 GmMAPKs 的单倍型分析，我们鉴定出一个与盐相关的 MAPK 成员 GmMMK1。GmMMK1 具有显著的序列变异，这影响大豆在发芽阶段的耐盐性。此外，大豆毛状根中 GmMMK1 的过表达对根生长有显著的负影响，导致 GmMMK1-OE 植物对盐胁迫更加敏感。此外，在拟南芥中异源表达 GmMMK1 也观察到对盐胁迫下的发芽和根生长有负影响。转录组分析和酵母双杂交筛选表明，激素信号和活性氧的稳态参与了 GmMMK1 的调控网络。总之，这项工作的结果表明，GmMMK1 是盐胁迫反应的一个重要负调控因子，为理解 MAPKs 在大豆盐信号转导中的作用提供了更好的认识。
