Rice CYP703A3, a cytochrome P450 hydroxylase, is essential for development of anther cuticle and pollen exine. Issue 10 (15th July 2014)

• Record Type: Journal Article
• Authors: Yang, Xijia; Wu, Di; Shi, Jianxin; He, Yi; Pinot, Franck; Grausem, Bernard; Yin, Changsong; Zhu, Lu; Chen, Mingjiao; Luo, Zhijing; Liang, Wanqi; Zhang, Dabing
• Is Part Of: Journal of integrative plant biology. Volume 56:Issue 10(2014)
• Page Start: 979
• Page End: 994
• Publication Date: 2014-07-15
• Subjects: Plants -- Periodicals; Plants -- China -- Periodicals; Electronic journals; 580.5
• DOI: 10.1111/jipb.12212
• Languages: English
• ISSNs: 1672-9072

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="jipb12212-sec-0001" sec-type="section"> <p>Anther cuticle and pollen exine act as protective envelopes for the male gametophyte or pollen grain, but the mechanism underlying the synthesis of these lipidic polymers remains unclear. Previously, a tapetum‐expressed CYP703A3, a putative cytochrome P450 fatty acid hydroxylase, was shown to be essential for male fertility in rice (<italic>Oryza sativa</italic> L.). However, the biochemical and biological roles of CYP703A3 has not been characterized. Here, we observed that <italic>cyp703a3‐2</italic> caused by one base insertion in <italic>CYP703A3</italic> displays defective pollen exine and anther epicuticular layer, which differs from <italic>Arabidopsis cyp703a2</italic> in which only defective pollen exine occurs. Consistently, chemical composition assay showed that levels of cutin monomers and wax components were dramatically reduced in <italic>cyp703a3‐2</italic> anthers. Unlike the wide range of substrates of <italic>Arabidopsis</italic> CYP703A2, CYP703A3 functions as an in‐chain hydroxylase only for a specific substrate, lauric acid, preferably generating 7‐hydroxylated lauric acid. Moreover, chromatin immunoprecipitation and expression analyses revealed that the expression of <italic>CYP703A3</italic> is directly regulated by <italic>Tapetum Degeneration Retardation</italic>, a known regulator of tapetum PCD and pollen exine formation. Collectively, our results suggest that CYP703A3 represents a conserved and diversified biochemical pathway for in‐chain hydroxylation of lauric acid required for the development of male organ in higher plants.</p> </sec> </abstract>