Beta Hydroxylation of Glycolipids from Ustilago maydis and Pseudozyma flocculosa by an NADPH-Dependent β-Hydroxylase
Beta Hydroxylation of Glycolipids from Ustilago maydis and Pseudozyma flocculosa by an NADPH-Dependent β-Hydroxylase
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DOI：
10.1128/aem.05822-11
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发表时间：
2011-11-01
影响因子：
4.4
通讯作者：
Belanger, Richard R.
中科院分区：
文献类型：
--
作者：
Teichmann, Beate;Lefebvre, Francois;Belanger, Richard R.
絮凝菌素（Flocculosin）和稻曲酸（Ustilagic acid，UA）是两种高度相似的纤维二糖类抗真菌物质，分别由生防菌絮凝假酵母（Pseudozyma flocculosa）和玉米黑粉菌（Ustilago maydis）产生。两种糖脂都含有在β位羟基化的短链脂肪酸，但长链脂肪酸不同，其在UA中的α位和在絮凝蛋白中的β位羟基化。在这两种生物体中，生物合成基因排列成大簇。大部分基因的功能已被鉴定，但絮状滨藜fhd1基因及其同源基因的功能尚不清楚。maydis、uhd1仍然未定义。推导的氨基酸序列与短链淀粉酶和还原酶（SDR）的氨基酸序列具有同源性。我们在U.并分析了分泌的UA。uhd1缺失菌株产生的UA缺乏短链脂肪酸的β-羟基。为了分析絮状委陵菜Fhd1的功能，将其相应的基因与U.玉米Delta uhd1突变体。Fhd1能够恢复野生型UA生产，表明Fhd1负责絮凝蛋白短链脂肪酸的β羟基化。我们还研究了一个P. flocculosa同系物的U。玉米长链脂肪酸α羟化酶Ahd1。将不属于絮状体蛋白基因簇的絮状体蛋白ahd1基因导入到美国大豆中。玉米Delta ahd 1突变株。P.flocculosa Ahd 1与U.玉米Δ ahd 1表型也不导致β-羟基化UA的产生。这表明絮状毕赤酵母Ahd1不参与絮状菌素羟基化。
Flocculosin and ustilagic acid (UA), two highly similar antifungal cellobiose lipids, are respectively produced by Pseudozyma flocculosa, a biocontrol agent, and Ustilago maydis, a plant pathogen. Both glycolipids contain a short-chain fatty acid hydroxylated at the beta position but differ in the long fatty acid, which is hydroxylated at the alpha position in UA and at the beta position in flocculosin. In both organisms, the biosynthesis genes are arranged in large clusters. The functions of most genes have already been characterized, but those of the P. flocculosa fhd1 gene and its homolog from U. maydis, uhd1, have remained undefined. The deduced amino acid sequences of these genes show homology to those of short-chain dehydrogenases and reductases (SDR). We disrupted the uhd1 gene in U. maydis and analyzed the secreted UA. uhd1 deletion strains produced UA lacking the beta-hydroxyl group of the short-chain fatty acid. To analyze the function of P. flocculosa Fhd1, the corresponding gene was used to complement U. maydis Delta uhd1 mutants. Fhd1 was able to restore wild-type UA production, indicating that Fhd1 is responsible for beta hydroxylation of the flocculosin short-chain fatty acid. We also investigated a P. flocculosa homolog of the U. maydis long-chain fatty-acid alpha hydroxylase Ahd1. The P. flocculosa ahd1 gene, which does not reside in the flocculosin gene cluster, was introduced into U. maydis Delta ahd1 mutant strains. P. flocculosa Ahd1 neither complemented the U. maydis Delta ahd1 phenotype nor resulted in the production of beta-hydroxylated UA. This suggests that P. flocculosa Ahd1 is not involved in flocculosin hydroxylation.