KIRA1 and ORESARA1 terminate flower receptivity by promoting cell death in the stigma of Arabidopsis

First author: Zhen Gao; Affiliations: Ghent University (根特大学): Ghent, Belgium

Corresponding author: Moritz K. Nowack

Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity (花可授性) by intercepting (拦截) pollen and initiating pollen tube growth toward the ovary (子房). In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity (长寿) by controlling the expression of programmed cell death–associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate (适度的) extension of flower receptivity, suggesting that additional processes participate in the control of the flower’s receptive life span.

花具有物种特异性的发挥功能的时间，决定了植物授粉、受精及座果发生的时间。柱头组织通过拦截花粉和起始花粉管向子房生长，在花可授性中发挥关键作用。本文揭示了拟南芥中终止柱头细胞处于功能化时间的细胞程序性死亡。作者鉴定了叶片衰老调控子ORESARA1和先前未被鉴定的KIRA1，这两个转录因子存在功能部分冗余，均通过控制细胞程序性死亡相关基因的表达调控柱头寿命。KIRA1基因的表达足以诱导细胞死亡和终止花的可授性，同时缺失KIRA1和ORESARA1会增加柱头的寿命。有趣的是，延长柱头的寿命对于花可授性的延长作用并不明显，显然存在其它的生物学过程参与花可授性的分子调控。

通讯：Moritz K. Nowack (http://www.vib.be/en/research/scientists/Pages/Moritz-Nowack-Lab.aspx)

研究方向：植物营养生长和生殖生长过程中的细胞程序性死亡。

doi: 10.1038/s41477-018-0160-7

Journal: Nature Plants

Published online: 28 May, 2018

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