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Regulation of ovule initiation by gibberellins and brassinosteroids in tomato and Arabidopsis: two plant species, two molecular mechanisms
First author: Daniela Barro‐Trastoy; Affiliations: Universidad Politécnica de Valencia (瓦倫西亞理工大學): Valencia, Spain
Corresponding author: Miguel A. Pérez‐Amador
Ovule primordia formation is a complex developmental process with a strong impact on the production of seeds. In Arabidopsis this process is controlled by a gene network, including components of the signaling pathways of auxin, brassinosteroids (BRs) and cytokinins. Recently, we have shown that gibberellins (GAs) also play an important role in ovule primordia initiation, inhibiting ovule formation in both Arabidopsis and tomato. Here we reveal that BRs also participate in the control of ovule initiation in tomato, by promoting an increase on ovule primordia formation. Moreover, molecular and genetic analyses of the co‐regulation by GAs and BRs of the control of ovule initiation indicate that two different mechanisms occur in tomato and Arabidopsis. In tomato, GAs act downstream of BRs. BRs regulate ovule number through the downregulation of GA biosynthesis, which provokes a stabilization of DELLA proteins that will finally promote ovule primordia initiation. In contrast, in Arabidopsis both GAs and BRs regulate ovule number independently of the activity levels of the other hormone. Taking together, our data strongly suggest that different molecular mechanisms could operate in different plant species to regulate identical developmental processes even, as in the case of ovule primordia initiation, when the same set of hormones trigger similar responses, adding a new level of complexity.
胚珠原基的形成是一個複雜的發育進程,其對於種子產量具有非常強烈的影響。在擬南芥中,胚珠原基的形成由一個基因網絡調控,包括生長素、油菜素內酯以及細胞分裂素的信號通路上的組分。最近,作者發現赤黴素在胚珠原基的起始過程中也發揮重要作用,在擬南芥和西紅柿中均能夠抑制胚珠的形成。本文中,作者發現西紅柿中油菜素內酯通過促進胚珠原基的形成作用於胚珠的起始。此外,針對赤黴素和油菜素內酯共調控胚珠起始的分子和遺傳學試驗顯示西紅柿和擬南芥中採用了兩套不同的分子機制。在西紅柿中,赤黴素作用於油菜素內酯的下遊。油菜素內酯能夠下調赤黴素的生物合成,減少由赤黴素誘導的DELLA蛋白降解,最終促進胚珠原基的起始,從而調控胚珠的數量。相反,在擬南芥中,赤黴素和油菜素內酯都獨立於其它植物激素的影響,調控胚珠的數量。綜上,本文的研究說明了不同的植物物種發展出了不同的分子機制來實現共同的發育進程,本文中也就是胚珠原基的起始,而同一類的植物激素誘導了相似的響應,所以增加了新的複雜程度。
通訊:Miguel A. Pérez‐Amador (http://www.ibmcp.upv.es/es/personas/mperezaibmcpupves)
個人簡介:1990年,瓦倫西亞大學,學士;1991-1995年,西班牙IBMCP,博士;1996-2001年,密西根州立大學,博士後。
研究方向:植物激素對於坐果和果實發育的影響,尤其是赤黴素在胚珠和種子發育中的作用。
doi: https://doi.org/10.1111/tpj.14684
Journal: the plant journal
First Published: January 13, 2020