Engineering Research Centre of Cotton, Ministry of Education/College of Agriculture, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi, 830052, China.
Institute of Cash Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, 830052, China.
BMC Plant Biol. 2022 Sep 1;22(1):421. doi: 10.1186/s12870-022-03804-5.
Serine carboxypeptidase-like protein (SCPL) plays an important role in response to stress in plant. However, our knowledge of the function of the SCPL gene family is limited.
In this study, a comprehensive and systematic analysis of SCPL gene family was conducted to explore the phylogeny and evolution of the SCPL gene in Gossypium hirsutum. The phenotype and molecular mechanism of silencing of the Gh_SCPL42 under Verticillium wilt stress was also studied. Our results showed that 96 SCPL genes were observed in genome of G. hirsutum, which distributed on 25 chromosomes and most of them were located in the nucleus. The phylogenetic tree analysis showed that members of SCPL gene family can be divided into three subgroups in G. hirsutum, which are relatively conservative in evolution. SCPL gene has a wide range of tissue expression types in G. hirsutum. Promoter analysis showed that the most cis-acting elements related to MeJA and ABA were contained. Through RNA-seq combined with genotyping, it was found that 11 GhSCPL genes not only had significant expression changes during Verticillium wilt stress but also had differential SNPs in the upstream, downstream, exonic or intronic regions. The expression of these 11 genes in the resistant (Zhongzhimian 2) and susceptible (Junmian 1) materials was further analyzed by qRT-PCR, it was found that 6 genes showed significant expression differences in the two materials. Among them, Gh_SCPL42 has the most obvious expression change. Furthermore, virus-induced gene silencing (VIGS) showed necrosis and yellowing of leaves and significantly higher disease severity index (DSI) and disease severity rate (DSR) values in VIGS plants than in control silenced Gh_SCPL42 plants. Moreover, the expression levels of genes related to the SA and JA pathways were significantly downregulated. These results show that Gh_SCPL42 might improve resistance to Verticillium wilt through the SA and JA pathways in G. hirsutum.
In conclusion, our findings indicated that Gh_SCPL42 gene plays an important role in resistance to Verticillium wilt in cotton. It was provided an important theoretical basis for further research on the function of SCPL gene family and the molecular mechanism of resistance to Verticillium wilt in cotton.
丝氨酸羧肽酶样蛋白（SCPL）在植物应激反应中发挥着重要作用。然而，我们对 SCPL 基因家族的功能知之甚少。
本研究对棉属 SCPL 基因家族进行了全面系统的分析，探讨了 SCPL 基因在陆地棉中的系统发育和进化。还研究了沉默 Gh_SCPL42 基因在黄萎病胁迫下的表型和分子机制。结果表明，在陆地棉基因组中观察到 96 个 SCPL 基因，它们分布在 25 条染色体上，大多数位于细胞核中。系统发育树分析表明，SCPL 基因家族的成员在进化上可分为 3 个亚组，相对保守。SCPL 基因在陆地棉中有广泛的组织表达类型。启动子分析表明，含有与 MeJA 和 ABA 相关的大多数顺式作用元件。通过 RNA-seq 结合基因分型发现，11 个 GhSCPL 基因不仅在黄萎病胁迫下表达发生显著变化，而且在上游、下游、外显子或内含子区域存在差异 SNP。通过 qRT-PCR 进一步分析了这 11 个基因在抗（中棉 2 号）和感（军棉 1 号）材料中的表达，发现这 6 个基因在两种材料中均有显著差异表达。其中，Gh_SCPL42 的表达变化最为明显。进一步的病毒诱导基因沉默（VIGS）显示，VIGS 植株的叶片坏死和黄化，以及严重度指数（DSI）和严重度率（DSR）值明显高于对照沉默 Gh_SCPL42 植株。此外，SA 和 JA 途径相关基因的表达水平显著下调。这些结果表明，Gh_SCPL42 可能通过陆地棉中的 SA 和 JA 途径提高对黄萎病的抗性。
综上所述，本研究结果表明 Gh_SCPL42 基因在棉花抗黄萎病中发挥着重要作用，为进一步研究 SCPL 基因家族的功能和棉花抗黄萎病的分子机制提供了重要的理论依据。
