Anther Endothecium-Derived Very-Long-Chain Fatty Acids Facilitate Pollen Hydration in Arabidopsis
Anther Endothecium-Derived Very-Long-Chain Fatty Acids Facilitate Pollen Hydration in Arabidopsis
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花药内皮衍生的长链脂肪酸促进拟南芥花粉水合
DOI：
10.1016/j.molp.2018.05.002
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发表时间：
2018
期刊：
影响因子：
27.5
通讯作者：
Yang Zhong Nan
中科院分区：
文献类型：
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作者：
Zhan Huadong;Xiong Haibo;Wang Shui;Yang Zhong Nan
花粉水合作用是花粉萌发和随后的花粉管生长的先决条件。作为二十年的生物化学研究和eceriferum（cer）雄性不育突变体的遗传鉴定的结果，众所周知，花粉衣中的极长链脂肪酸（VLCFA）脂质在花粉水合中起关键作用（Preuss et al.，1993; Fiebig等人，2000; Hiscock和艾伦，2008）。VLCFA是指具有20个或更多个碳的脂肪酸，其通过由3-酮脂酰-CoA合酶（KCS）、3-酮脂酰-CoA还原酶（KCR）、3-羟脂酰-CoA脱氢酶和烯酰还原酶（ECR）催化的四个连续反应合成。在所有反应中，KCS介导的缩合是限速步骤，并决定最终酰基辅酶A产物的长度（Haslam和Kunst，2013）。KCS 6（也称为CER 6、POP 1和CUT 1）催化C28脂肪酰基-CoA的产生，并且对于花粉水合是必需的（Fiebig等人，2000; Haslam和Kunst，2013）。此外，BAHD酰基转移酶CER 2/CER 2样蛋白是VLCFA合成所需的（Xia et al.，1997; Haslam等人，2012年、2015年）。有人提出，CER 2/CER 2样蛋白通过与特异性KCS酶结合，作为VLCFA延伸机制的新组分发挥作用（Haslam和Kunst，2013）。在低湿度环境下，CER 2与CER 2样2（CER 2L 2）冗余地作用以影响雄性生育力（Haslam等人，2015），表明CER 2和CER 2L 2可能参与花粉水合作用。为了研究VLCFAs在花粉水合中的作用，我们从诺丁汉拟南芥种质中心获得了cer 2（SALK_084443，At 4g 24510）和cer 2l 2（SAIL_3_F11，At 3g 23840）的T-DNA插入等位基因。我们发现cer 2 cer 2l 2双突变体显示出如所述的雄性不育性（Haslam et al.，2015），而CER 2/cer 2; cer 2l 2/cer 2l 2植物显示降低的育性，而cer 2/cer 2; CER 2L 2/cer 2l 2是可育的（补充图1），表明CER 2L 2在植物育性中起主要作用。从基因上看，自交后代-
Pollen hydration is a prerequisite for pollen germination and subsequent pollen tube growth. As a result of two decades of biochemical studies and genetic identification of the eceriferum (cer) male-sterile mutants, the very-long-chain fatty acid (VLCFA) lipids in the pollen coat have been well known to play a critical role in pollen hydration (Preuss et al., 1993; Fiebig et al., 2000; Hiscock and Allen, 2008). VLCFAs are referred to as fatty acids with 20 or more carbons, which are synthesized through four sequential reactions catalyzed by 3-ketoacyl-CoA synthase (KCS), 3-ketoacyl-CoA reductase (KCR), 3-hydroxyacyl-CoA dehydratase, and enoyl reductase (ECR). Among all the reactions, KCS-mediated condensation is the rate-limiting step and determines the length of the final acyl-CoA products (Haslam and Kunst, 2013). KCS6 (also known as CER6, POP1, and CUT1) catalyzes the production of C28 fatty acyl-CoAs and is essential for pollen hydration (Fiebig et al., 2000; Haslam and Kunst, 2013). In addition, BAHD acyltransferase CER2/CER2-like proteins are required for VLCFAs synthesis (Xia et al., 1997; Haslam et al., 2012, 2015). It was proposed that CER2/CER2-like proteins function as novel components of the VLCFA elongation machinery through association with the specific KCS enzyme (Haslam and Kunst, 2013). CER2 acts redundantly with CER2-like2 (CER2L2) to affect male fertility under low-humidity environments (Haslam et al., 2015), indicating that CER2 and CER2L2 are likely involved in pollen hydration. However, the cytological and genetic evidence of CER2 and CER2L2 in male sterility remains elusive.To investigate the role of VLCFAs in pollen hydration, we obtained and studied T-DNA insertion alleles of cer2 (SALK_084443, At4g24510) and cer2l2 (SAIL_3_F11, At3g23840) from Nottingham Arabidopsis Stock Centre. We found that the cer2 cer2l2 double mutant showed male sterility as described (Haslam et al., 2015), whereas the CER2/cer2; cer2l2/cer2l2 plants displayed reduced fertility while cer2/cer2; CER2L2/cer2l2 was fertile (Supplemental Figure 1), indicating that CER2L2 plays a major role in plant fertility. Genotypically, the self-crossed prog-