Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, P. R.China.
Hebei Key Laboratory of Horticultural Germplasm Excavation and Innovative Utilization, Hebei Normal University of Science & Technology, Qinhuangdao 066004, P. R.China.
Plant Cell. 2024 Oct 3;36(10):4607-4621. doi: 10.1093/plcell/koae228.
Complete disruption of critical genes is generally accompanied by severe growth and developmental defects, which dramatically hinder its utilization in crop breeding. Identifying subtle changes, such as single-nucleotide polymorphisms (SNPs), in critical genes that specifically modulate a favorable trait is a prerequisite to fulfill breeding potential. Here, we found 2 SNPs in the E-class floral organ identity gene cucumber (Cucumis sativus) SEPALLATA2 (CsSEP2) that specifically regulate fruit length. Haplotype (HAP) 1 (8G2667A) and HAP2 (8G2667T) exist in natural populations, whereas HAP3 (8A2667T) is induced by ethyl methanesulfonate mutagenesis. Phenotypic characterization of 4 near-isogenic lines and a mutant line showed that HAP2 fruits are significantly longer than those of HAP1, and those of HAP3 are 37.8% longer than HAP2 fruit. The increasing fruit length in HAP1-3 was caused by a decreasing inhibitory effect on CRABS CLAW (CsCRC) transcription (a reported positive regulator of fruit length), resulting in enhanced cell expansion. Moreover, a 7638G/A-SNP in melon (Cucumis melo) CmSEP2 modulates fruit length in a natural melon population via the conserved SEP2-CRC module. Our findings provide a strategy for utilizing essential regulators with pleiotropic effects during crop breeding.
关键基因的完全缺失通常伴随着严重的生长和发育缺陷，这极大地阻碍了其在作物育种中的应用。鉴定关键基因中特异性调节有利性状的细微变化，如单核苷酸多态性 (SNP)，是充分发挥其育种潜力的前提。在这里，我们发现黄瓜 E 类花器官身份基因 SEPALLATA2 (CsSEP2) 中有 2 个 SNP，它们特异性地调节果实长度。单倍型 (HAP) 1（8G2667A）和 HAP2（8G2667T）存在于自然种群中，而 HAP3（8A2667T）是由乙基甲磺酸诱变诱导的。对 4 个近等基因系和一个突变系的表型特征进行分析表明，HAP2 果实明显长于 HAP1，而 HAP3 果实比 HAP2 长 37.8%。HAP1-3 中果实长度的增加是由于对 CRABS CLAW (CsCRC) 转录的抑制作用降低（被报道为果实长度的正调节剂），导致细胞扩张增强。此外，甜瓜 (Cucumis melo) CmSEP2 中的一个 7638G/A-SNP 通过保守的 SEP2-CRC 模块调节自然甜瓜群体中的果实长度。我们的研究结果为利用作物育种中具有多效性的必需调节剂提供了一种策略。
