College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China.
Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, China.
J Exp Bot. 2018 Nov 26;69(22):5373-5387. doi: 10.1093/jxb/ery329.
The WUSCHEL-related homeobox1 (WOX1) transcription factor plays an important role in lateral growth of plant organs; however, the underlying mechanisms in the regulation of reproductive development are largely unknown. Cucumber (Cucumis sativus) has separate male and female flowers, facilitating the study of the role of WOX1 in stamen and carpel development. Here, we identified a mango fruit (mf) mutant in cucumber, which displayed multiple defects in flower growth as well as male and female sterility. Map-based cloning showed that Mf encodes a WOX1-type transcriptional regulator (CsWOX1), and that the mf mutant encodes a truncated protein lacking the conserved WUS box. Further analysis showed that elevated expression of CsWOX1 was responsible for the mutant phenotype in cucumber and Arabidopsis. Comparative transcriptome profiling revealed certain key players and CsWOX1-associated networks that regulate reproductive development. CsWOX1 directly interacts with cucumber SPOROCYTELESS (CsSPL), and many genes in the CsSPL-mediated pathway were down-regulated in plants with the mutant allele at the Mf locus. In addition, auxin distribution was affected in both male and female flowers of the mutant. Taking together, these data suggest that CsWOX1 may regulate early reproductive organ development and be involved in sporogenesis via the CsSPL-mediated pathway and/or modulate auxin signaling in cucumber.
WUSCHEL 相关同源盒 1（WOX1）转录因子在植物器官的侧向生长中发挥重要作用；然而，其在生殖发育调控中的作用机制在很大程度上尚不清楚。黄瓜（Cucumis sativus）具有单独的雄花和雌花，这有利于研究 WOX1 在雄蕊和心皮发育中的作用。在这里，我们在黄瓜中鉴定到一个芒果果实（mf）突变体，其在花生长以及雄性和雌性不育方面表现出多种缺陷。基于图谱的克隆表明，Mf 编码一个 WOX1 型转录调节剂（CsWOX1），而 mf 突变体编码一种缺少保守 WUS 盒的截断蛋白。进一步的分析表明，CsWOX1 的高表达导致了黄瓜和拟南芥中突变体的表型。比较转录组分析揭示了某些关键因子和 CsWOX1 相关网络，它们调节生殖发育。CsWOX1 与黄瓜 SPOROCYTELESS（CsSPL）直接相互作用，并且在 Mf 基因座具有突变等位基因的植物中，CsSPL 介导途径中的许多基因表达下调。此外，在突变体的雄花和雌花中，生长素的分布都受到了影响。综上所述，这些数据表明 CsWOX1 可能通过 CsSPL 介导的途径调节早期生殖器官发育和参与孢子发生，以及调节黄瓜中的生长素信号。
