Ethylene plays a dual role in sex determination and fruit shape in cucurbits

第一作者：Adnane Boualem

第一单位：巴黎萨克雷大学

通讯作者：Abdelhafid Bendahmane

 Abstarct 

背景回顾：Shapes of vegetables and fruits are the result of adaptive evolution and human selection. Modules controlling organ shape have been identified. However, little is known about signals coordinating organ development and shape. 

蔬菜和水果的形状是适应性演化和人类选择的结果。控制器官形状的模块已经被鉴定。然而，我们对于协调器官发育和形状的信号还所知甚少。

主要研究：Here, we describe the characterization of a melon mutation rf1, leading to round fruit. 

本文中，作者发现甜瓜rf1突变会导致导致圆果。

结果1-圆果突变体及致变基因克隆、功能鉴定：Histological analysis of rf1 flower and fruits revealed fruit shape is determined at flower stage 8, after sex determination and before flower fertilization. Using positional cloning, we identified the causal gene as the monoecy sex determination gene CmACS7, and survey of melon germplasms showed strong association between fruit shape and sexual types. We show that CmACS7-mediated ethylene production in carpel primordia enhances cell expansion and represses cell division, leading to elongated fruit. 

rf1突变体花和果实的组织学分析显示，果实形状在性别决定后、花受精前的花期8阶段被决定。通过定位克隆，作者发现CmACS7基因是雌雄异花同株中的性别决定基因；并且，通过对甜瓜种质资源的调查表明，果实形状和性别类型之间存在强烈的关联。作者发现，心皮原基中由CmACS7介导的乙烯生成增强了细胞扩张，抑制了细胞分裂，导致果实伸长。

结果2-排除核内复制：Cell size is known to rise as a result of endoreduplication. At stage 8 and anthesis, we found no variation in ploidy levels between female and hermaphrodite flowers, ruling out endoreduplication as a factor in fruit shape determination. 

已有研究表明，核内复制会增加细胞的大小。在花发育第8阶段和开花期，作者发现雌花和两性花细胞的倍性水平没有变化，从而排除了核内复制是决定果实形状的重要因素。

结果3-CmACS7介导圆果形成的调控机制：To pinpoint the gene networks controlling elongated versus round fruit phenotype, we analyzed the transcriptomes of laser capture microdissected carpels of wild-type and rf1 mutant. These high-resolution spatiotemporal gene expression dynamics revealed the implication of two regulatory modules. The first module implicates E2F-DP transcription factors, controlling cell elongation versus cell division. The second module implicates OVATE- and TRM5-related proteins, controlling cell division patterns. 

为了精确定位控制长果和圆果表型的基因网络，作者利用激光捕获显微切割结合转录组测序的方法获取了野生型和rf1突变体的心皮转录组。这些高分辨率的时空基因表达动态揭示了有两个调控模块可能牵涉其中。第一个模块涉及到了E2F-DP转录因子，主要控制细胞的伸长和细胞的分裂。第二个模块则涉及OVATE和TRM5相关蛋白，主要控制细胞的分裂模式。

结论：Our finding highlights the dual role of ethylene in the inhibition of the stamina development and the elongation of ovary and fruit in cucurbits.

本文的研究结果强调了乙烯在抑制葫芦科瓜类植物雄蕊发育以及子房和果实伸长中的双重作用。

doi: https://doi.org/10.1016/j.cub.2022.04.031

Journal: Current Biology

Published date: May 06, 2022