Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan, ROC.
Advanced Plant and Food Crop Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan, ROC.
Commun Biol. 2023 May 8;6(1):498. doi: 10.1038/s42003-023-04864-5.
We previously found that the RING-type E3 ligase DEFECTIVE IN ANTHER DEHISCENCE1- (DAD1-) Activating Factor (DAF) controls anther dehiscence by activating the jasmonate biosynthetic pathway in Arabidopsis. Here, we show that in Arabidopsis, the DAF ancestor was duplicated into three genes (DAF, Ovule Activating Factor (OAF), DAFL2), which evolved divergent partial functions from their ancestor through subfunctionalization. In this case, DAF-DAD1-JA signaling regulates anther dehiscence, whereas OAF controls ovule development by negatively regulating cinnamyl alcohol dehydrogenase 9 (CAD9) activity and being negatively regulated by miR847 itself in Arabidopsis. Downregulation of OAF or upregulation of CAD9 and miR847 caused similar abortion of ovule formation due to precocious ovule lignification in transgenic Arabidopsis. Interestingly, only one DAF-like gene, PaOAF, exists in the monocot orchids, which has likely evolved through nonfunctionalization and maintains a conserved function as Arabidopsis OAF in regulating ovule development since defective ovules were observed in the virus-induced gene silencing (VIGS) PaOAF Phalaenopsis orchids. The absence of the DAF ortholog and its function in orchids is likely due to the evolution of stamens to a unique pollinium structure that lacks the feature of anther dehiscence. These findings expand the current knowledge underlying the multifunctional evolution and diverse functionalization of duplicate gene pairs within/among plants.
我们之前发现，RING 型 E3 连接酶 DEFECTIVE IN ANTHER DEHISCENCE1-（DAD1-）激活因子（DAF）通过激活拟南芥中的茉莉酸生物合成途径来控制花粉囊开裂。在这里，我们表明，在拟南芥中，DAF 的祖先被复制为三个基因（DAF、胚珠激活因子（OAF）、DAFL2），它们通过亚功能化从祖先那里进化出了不同的部分功能。在这种情况下，DAF-DAD1-JA 信号转导调节花粉囊开裂，而 OAF 通过负调控肉桂醇脱氢酶 9（CAD9）活性并受 miR847 自身的负调控来控制胚珠发育。在转基因拟南芥中，下调 OAF 或上调 CAD9 和 miR847 会因胚珠木质素化过早而导致胚珠形成相似的败育。有趣的是，单子叶兰花中只有一个 DAF 样基因 PaOAF，它可能是通过非功能化进化而来的，并且由于在病毒诱导的基因沉默（VIGS）中观察到缺陷胚珠，它在调节胚珠发育方面保持了拟南芥 OAF 的保守功能。兰花中 DAF 同源基因的缺失及其功能可能是由于雄蕊进化为具有独特花粉体结构的特征，缺乏花粉囊开裂的特征。这些发现扩展了目前对植物内/间多功能进化和重复基因对多样化功能化的理解。
