Kim Hyun Min, Park Se Hee, Ma Sang Hoon, Park Seo Young, Yun Chul-Ho, Jang Geupil, Joung Young Hee
School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea.
Front Plant Sci. 2020 Dec 8;11:583767. doi: 10.3389/fpls.2020.583767. eCollection 2020.
Abscisic acid (ABA) is a key signaling molecule that mediates plant response to stress. Increasing evidence indicates that ABA also regulates many aspects of plant development, such as seed germination, leaf development, and ripening. ABA metabolism, including ABA biosynthesis and degradation, is an essential aspect of ABA response in plants. In this study, we identified four cytochrome P450 genes (, , , and ) that mediate ABA hydroxylation, which is required for ABA degradation in . We observed that CaCYP707A-mediated ABA hydroxylation promotes ABA degradation, leading to low levels of ABA and a dehydration phenotype in plants. Importantly, seed formation was strongly inhibited in plants, and a cross-pollination test suggested that the defect in seed formation is caused by improper pollen development. Phenotypic analysis showed that pollen maturation is suppressed in plants. Consequently, most pollen grains degenerated, unlike non-transgenic (NT) pollen, which developed into mature pollen grains. Together our results indicate that CaCYP707A mediates ABA hydroxylation and thereby influences pollen development, helping to elucidate the mechanism underlying ABA-regulated pollen development.
脱落酸（ABA）是一种介导植物对胁迫作出反应的关键信号分子。越来越多的证据表明，ABA还调控植物发育的许多方面，如种子萌发、叶片发育和成熟。ABA代谢，包括ABA生物合成和降解，是植物中ABA响应的一个重要方面。在本研究中，我们鉴定了四个介导ABA羟基化的细胞色素P450基因（、、和），ABA羟基化是植物中ABA降解所必需的。我们观察到CaCYP707A介导的ABA羟基化促进ABA降解，导致植物中ABA水平降低和脱水表型。重要的是，植物中的种子形成受到强烈抑制，异花授粉试验表明种子形成缺陷是由花粉发育不当引起的。表型分析表明，植物中的花粉成熟受到抑制。因此，与发育成成熟花粉粒的非转基因（NT）花粉不同，大多数植物花粉粒退化。我们的结果共同表明，CaCYP707A介导ABA羟基化，从而影响花粉发育，有助于阐明ABA调控花粉发育的潜在机制。
