Cytochrome P450 Family Member CYP704B2 Catalyzes the ω-Hydroxylation of Fatty Acids and Is Required for Anther Cutin Biosynthesis and Pollen Exine Formation in Rice
Cytochrome P450 Family Member CYP704B2 Catalyzes the ω-Hydroxylation of Fatty Acids and Is Required for Anther Cutin Biosynthesis and Pollen Exine Formation in Rice
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DOI：
10.1105/tpc.109.070326
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发表时间：
2010-01-01
期刊：
影响因子：
11.6
通讯作者：
Zhang, Dabing
中科院分区：
文献类型：
--
作者：
Li, Hui;Pinot, Franck;Zhang, Dabing
花药角质层和小孢子外壁作为保护屏障的雄配子体和花粉粒，但相对知之甚少的机制，其组成的单体的生物合成。本文报道了一个水稻雄性不育突变体cyp 704 B2的分离和鉴定，该突变体具有膨大的孢子体绒毡层，败育的花粉粒没有可检测到的外壁，花药角质层不发达。此外，化学成分分析表明，cyp 704 B2花药中几乎检测不到角质单体。这些缺陷是由细胞色素P450家族基因CYP 704 B2突变引起的。CYP 704 B2转录本在花药发育第8阶段至第10阶段的绒毡层和小孢子中特异性检测到。CYP 704 B2在酵母中的异源表达证明CYP 704 B2催化具有16和18个碳链的v-羟基化脂肪酸的产生。我们的研究结果提供了见解的生物聚合物孢粉素和角质的生物合成。具体而言，我们的研究表明，ω-羟基化途径的脂肪酸依赖于这个古老的CYP 704 B家族，保守的从苔藓到被子植物，是必不可少的角质层和外壁在植物雄性生殖和孢子发育过程中的形成。
The anther cuticle and microspore exine act as protective barriers for the male gametophyte and pollen grain, but relatively little is known about the mechanisms underlying the biosynthesis of the monomers of which they are composed. We report here the isolation and characterization of a rice (Oryza sativa) male sterile mutant, cyp704B2, which exhibits a swollen sporophytic tapetal layer, aborted pollen grains without detectable exine, and undeveloped anther cuticle. In addition, chemical composition analysis indicated that cutin monomers were hardly detectable in the cyp704B2 anthers. These defects are caused by a mutation in a cytochrome P450 family gene, CYP704B2. The CYP704B2 transcript is specifically detected in the tapetum and the microspore from stage 8 of anther development to stage 10. Heterologous expression of CYP704B2 in yeast demonstrated that CYP704B2 catalyzes the production of v-hydroxylated fatty acids with 16 and 18 carbon chains. Our results provide insights into the biosynthesis of the two biopolymers sporopollenin and cutin. Specifically, our study indicates that the omega-hydroxylation pathway of fatty acids relying on this ancient CYP704B family, conserved from moss to angiosperms, is essential for the formation of both cuticle and exine during plant male reproductive and spore development.