Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas (CSIC), Valencia 46022, Spain.
IFEVA, Facultad de Agronomía, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires C1417DSE, Argentina.
Development. 2018 Jul 9;145(13):dev163865. doi: 10.1242/dev.163865.
Ovule formation is a complex developmental process in plants, with a strong impact on the production of seeds. Ovule primordia initiation is controlled by a gene network, including components of the signaling pathways of auxin, brassinosteroids and cytokinins. By contrast, gibberellins (GAs) and DELLA proteins, the negative regulators of GA signaling, have never been shown to be involved in ovule initiation. Here, we provide molecular and genetic evidence that points to DELLA proteins as novel players in the determination of ovule number in and in species of agronomic interest, such as tomato and rapeseed, adding a new layer of complexity to this important developmental process. DELLA activity correlates positively with ovule number, acting as a positive factor for ovule initiation. In addition, ectopic expression of a dominant DELLA in the placenta is sufficient to increase ovule number. The role of DELLA proteins in ovule number does not appear to be related to auxin transport or signaling in the ovule primordia. Possible crosstalk between DELLA proteins and the molecular and hormonal network controlling ovule initiation is also discussed.
胚珠形成是植物中一个复杂的发育过程，对种子的产生有很大的影响。胚珠原基的起始是由一个基因网络控制的，包括生长素、油菜素内酯和细胞分裂素信号通路的组成部分。相比之下，赤霉素（GAs）和 DELLA 蛋白，GA 信号的负调节剂，从未被证明参与胚珠起始。在这里，我们提供了分子和遗传证据，表明 DELLA 蛋白是 和农业上有重要意义的物种（如番茄和油菜）中决定胚珠数量的新的参与者，为这个重要的发育过程增添了新的复杂性。DELLA 活性与胚珠数量呈正相关，作为胚珠起始的一个正因子。此外，在胎盘中外源表达显性 DELLA 足以增加胚珠数量。DELLA 蛋白在胚珠数量中的作用似乎与胚珠原基中的生长素运输或信号无关。还讨论了 DELLA 蛋白与控制胚珠起始的分子和激素网络之间可能的串扰。
