Ye Xu, Deng Qinlin, Xu Shicheng, Huang Yifang, Wei Dayong, Wang Zhimin, Zhang Hongcheng, Wang Hebing, Tang Qinglin
College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China.
Chongqing Academy of Agricultural Sciences, Chongqing, 401329, China.
Plant Physiol Biochem. 2024 Feb;207:108395. doi: 10.1016/j.plaphy.2024.108395. Epub 2024 Jan 28.
Flowering is an important developmental transition that greatly affects the yield of many vegetable crops. In cucumber (Cucumis sativus), flowering is regulated by various factors including squamosa promoter-binding-like (SPL) family proteins. However, the role of CsSPL genes in cucumber flowering remains largely unknown. In this study, we cloned the squamosa promoter-binding-like protein 13A (CsSPL13A) gene, which encodes a highly conserved SBP-domain protein that acts as a transcription factor and localizes to the nucleus. Quantitative real-time PCR (qRT-PCR) analysis showed that CsSPL13A was mainly expressed in flowers, and its expression level increased significantly nearing the flowering stage. Additionally, compared with the wild type(WT), CsSPL13A-overexpressing transgenic cucumber plants (CsSPL13A-OE) showed considerable differences in flowering phenotypes, such as early flowering, increased number of male flowers, and longer flower stalks. CsSPL13A upregulated the expression of the flowering integrator gene Flowering Locus T (CsFT) and the sugar-mediated flowering gene β-amylase (CsBAM) in cucumber. Yeast one-hybrid and firefly enzyme reporter assays confirmed that the CsSPL13A protein could directly bind to the promoters of CsFT and CsBAM, suggesting that CsSPL13A works together with CsFT and CsBAM to mediate flowering in cucumber. Overall, our results provide novel insights into the regulatory network of flowering in cucumber as well as new ideas for the genetic improvement of cucumber varieties.
开花是一个重要的发育转变过程，极大地影响着许多蔬菜作物的产量。在黄瓜（Cucumis sativus）中，开花受多种因素调控，包括类鳞状启动子结合蛋白（SPL）家族蛋白。然而，CsSPL基因在黄瓜开花过程中的作用仍 largely未知。在本研究中，我们克隆了类鳞状启动子结合蛋白13A（CsSPL13A）基因，该基因编码一种高度保守的SBP结构域蛋白，作为转录因子并定位于细胞核。定量实时PCR（qRT-PCR）分析表明，CsSPL13A主要在花中表达，且在接近开花阶段时其表达水平显著增加。此外，与野生型（WT）相比，过表达CsSPL13A的转基因黄瓜植株（CsSPL13A-OE）在开花表型上表现出显著差异，如早花、雄花数量增加和花柄变长。CsSPL13A上调了黄瓜中开花整合基因开花位点T（CsFT）和糖介导的开花基因β-淀粉酶（CsBAM）的表达。酵母单杂交和萤火虫酶报告基因检测证实，CsSPL13A蛋白可直接结合到CsFT和CsBAM的启动子上，表明CsSPL13A与CsFT和CsBAM共同作用介导黄瓜开花。总体而言，我们的结果为黄瓜开花调控网络提供了新的见解，也为黄瓜品种的遗传改良提供了新思路。
