Evolutionary Conserved Function of Barley and Arabidopsis 3-KETOACYL-CoA SYNTHASES in Providing Wax Signals for Germination of Powdery Mildew Fungi1[C][W]
Evolutionary Conserved Function of Barley and Arabidopsis 3-KETOACYL-CoA SYNTHASES in Providing Wax Signals for Germination of Powdery Mildew Fungi1[C][W]
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DOI：
10.1104/pp.114.246348
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发表时间：
2014-09
期刊：
影响因子：
7.4
通讯作者：
Denise Weidenbach;Marcus Jansen;R. Franke;G. Hensel;W. Weissgerber;Sylvia Ulferts;Irina Jansen;L. Sc
中科院分区：
文献类型：
--
作者：
Denise Weidenbach;Marcus Jansen;R. Franke;G. Hensel;W. Weissgerber;Sylvia Ulferts;Irina Jansen;L. Sc
来自大麦和拟南芥的一对直系同源基因参与长链脂肪酸信号传导，这是远亲白粉病分生孢子萌发所需的。对于仅在有限数量的宿主植物物种上生存的植物病原真菌（例如白粉病）来说，至关重要的是它们的孢子感知到它们落在正确的位置以尽快开始发芽。我们研究了一种角质层外叶蜡减少的大麦（Hordeum vulgare）突变体，在该突变体上，适应和未适应的白粉病真菌的孢子显示出发芽减少。负责突变蜡表型的大麦基因在正向遗传筛选中被克隆，并被鉴定为编码 3-酮酰辅酶 A 合酶 (HvKCS6)，这是一种参与脂肪酸延伸的蛋白质，是合成角质层蜡所需的蛋白质。气相色谱-质谱分析表明，该突变体的链长在C-24以上的脂肪族蜡成分显着减少。突变体的互补恢复了野生型蜡并克服了萌发损失，表明突变体上较少存在的蜡成分是孢子萌发的关键线索。对拟南芥 (Arabidopsis thaliana) 转基因植物的研究显示，对适应和未适应的白粉病真菌具有相同的萌发表型，其中拟南芥具有角质蜡生产所需的拟南芥1（HvKCS6直向同源物）的正义沉默。我们的研究结果暗示了远缘白粉病中感知植物表面的进化保守机制，该机制基于 KCS6 衍生的蜡成分。对这种信号的感知一定是在大约 1.5 亿年前单子叶植物与双子叶植物分裂发生之前就已经进化的。
An orthologous pair of genes from barley and Arabidopsis is involved in long-chain fatty acid signaling that is required for germination of conidia from distantly related powdery mildews. For plant pathogenic fungi, such as powdery mildews, that survive only on a limited number of host plant species, it is a matter of vital importance that their spores sense that they landed on the right spot to initiate germination as quickly as possible. We investigated a barley (Hordeum vulgare) mutant with reduced epicuticular leaf waxes on which spores of adapted and nonadapted powdery mildew fungi showed reduced germination. The barley gene responsible for the mutant wax phenotype was cloned in a forward genetic screen and identified to encode a 3-KETOACYL-CoA SYNTHASE (HvKCS6), a protein participating in fatty acid elongation and required for synthesis of epicuticular waxes. Gas chromatography-mass spectrometry analysis revealed that the mutant has significantly fewer aliphatic wax constituents with a chain length above C-24. Complementation of the mutant restored wild-type wax and overcame germination penalty, indicating that wax constituents less present on the mutant are a crucial clue for spore germination. Investigation of Arabidopsis (Arabidopsis thaliana) transgenic plants with sense silencing of Arabidopsis REQUIRED FOR CUTICULAR WAX PRODUCTION1, the HvKCS6 ortholog, revealed the same germination phenotype against adapted and nonadapted powdery mildew fungi. Our findings hint to an evolutionary conserved mechanism for sensing of plant surfaces among distantly related powdery mildews that is based on KCS6-derived wax components. Perception of such a signal must have been evolved before the monocot-dicot split took place approximately 150 million years ago.