Segura María, García Alicia, Gamarra German, Benítez Álvaro, Iglesias-Moya Jessica, Martínez Cecilia, Jamilena Manuel
Department of Biology and Geology. Agri-food Campus of International Excellence (CeiA3) and Research Center CIAIMBITAL, University of Almería, 04120 Almería, Spain.
Hortic Res. 2024 Apr 22;11(6):uhae115. doi: 10.1093/hr/uhae115. eCollection 2024 Jun.
In monoecious species, female flowering constitutes the developmental process that determines the onset and production of fruit and is therefore closely related to crop yield. This article presents the identification and phenotypic and molecular characterization of , an ethylmethane sulfonate loss-of-function mutation that completely blocks the female floral transition, converting all female flowers into male flowers. BSA-seq analysis coupled with WGS showed that corresponds to a C>T transition in the coding region of the gene , generating a premature stop codon and a truncated transcription factor without its N-terminal effector domain. The phenotype was partially rescued by exogenous ethylene application, indicating that the function of is mediated by ethylene. Different evidence supports this conclusion: first, the reduced ethylene production of the mutant, and second, the male flower productive phenotype of the double mutant between and the ethylene-insensitive mutant , which demonstrated that is epistatic over . Furthermore, transcriptomic analysis of WT and apical shoots confirmed that regulates master sex-determining genes, upregulating those encoding the ethylene biosynthesis enzymes and and those encoding for transcription factors that promote the development of carpels(), but downregulating those involved in the arrest of carpels (), In the gene network controlling sex determination in cucurbits, CpMYB62 occupies the most upstream position, activating ethylene and other sex determining genes involved in female flower determination in .
在雌雄同株物种中,雌花发育过程决定了果实的起始和产量,因此与作物产量密切相关。本文介绍了一个由甲基磺酸乙酯诱导产生的功能缺失突变体的鉴定、表型及分子特征,该突变体完全阻断了雌花的转变,将所有雌花转化为雄花。基于全基因组重测序的混合分组分析法(BSA-seq)与全基因组测序(WGS)显示,该突变体对应于基因编码区的一个C>T转换,产生了一个提前终止密码子,导致转录因子截短,缺失其N端效应结构域。外源施加乙烯可部分恢复该突变体的表型,表明该基因的功能由乙烯介导。不同证据支持这一结论:其一,突变体乙烯产量降低;其二,该突变体与乙烯不敏感突变体的双突变体表型为雄花发育,表明该基因对乙烯不敏感突变体呈上位性。此外,对野生型和该突变体顶芽的转录组分析证实,该基因调控主要的性别决定基因,上调编码乙烯生物合成酶和促进心皮发育的转录因子的基因,但下调参与心皮发育停滞的基因。在葫芦科性别决定的基因网络中,CpMYB62占据最上游位置,激活乙烯及其他参与黄瓜雌花决定过程的性别决定基因。