Different chitin synthase genes are required for various developmental and plant infection processes in the rice blast fungus Magnaporthe oryzae.
Different chitin synthase genes are required for various developmental and plant infection processes in the rice blast fungus Magnaporthe oryzae.
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DOI：
10.1371/journal.ppat.1002526
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发表时间：
2012-02
期刊：
影响因子：
6.7
通讯作者：
Peng YL
中科院分区：
文献类型：
--
作者：
Kong LA;Yang J;Li GT;Qi LL;Zhang YJ;Wang CF;Zhao WS;Xu JR;Peng YL
几丁质是真菌细胞壁的主要成分，由几丁质酶合成。植物病原真菌通常具有多个几丁质合成酶基因。为了确定它们在发育和发病机制中的作用，我们对稻瘟病菌的所有7个CHS基因进行了功能鉴定。其中CHS1、CHS6和CHS7对植物侵染起重要作用。虽然chs6突变体是非致病性的，chs1和chs7突变体的毒力显着降低。CHS1在分生孢子发生中起着特殊的作用，分生孢子发生是自然侵染循环的一个重要步骤。大部分chs1分生孢子无隔膜，孢子顶端无粘液。chs6突变体的菌丝生长和产孢能力下降。它不能渗透并侵入植物细胞生长。两个含有MMD的几丁质合成酶基因CHS5和CHS6具有相似的表达模式。虽然缺失CHS5没有可检测的表型，chs5 chs6双突变体有更严重的缺陷比chs6突变体，这表明他们可能有重叠的功能，在维持营养和入侵菌丝的极化生长。与其他CHS基因不同，CHS7在附着胞形成中具有独特的功能。虽然chs7突变体在人工疏水表面上被芽管阻断形成附着胞，但在菌丝顶端或植物表面仍然产生黑化附着胞，表明几丁质合成酶基因对菌丝顶端和芽管形成附着胞有不同的影响。chs7突变体在附着胞穿透和侵入生长方面也有缺陷。总之，我们的研究结果表明，单个CHS基因在菌丝生长，分生孢子发生，附着胞发育和致病性中发挥着不同的作用。的，并提供了潜在的新线索，在控制这种毁灭性的病原体，针对特定的几丁质酶。几丁质是真菌细胞壁的主要成分之一，在菌丝顶端生长和真菌形态建成中起着重要作用。几丁质酶催化几丁质的生物合成，是一种著名的杀菌剂靶标。然而，几丁质合成酶基因的系统特性尚未报道在植物病原子囊菌。为了确定它们在发育和发病机制中的作用，在这项研究中，我们功能特征的所有7个几丁质合成酶基因（CHS1-CHS7）在Magnaporthe muscle，一个模型，用于研究真菌的发育和发病机制。虽然CHS2、CHS3、CHS4和CHS5对于植物感染是必需的，但CHS6对于致病性是必需的。chs6突变体不能穿透植物细胞并产生感染性菌丝。另外两个几丁质合成酶基因，CHS1和CHS7，也是重要的毒力。chs1和chs7突变体在水稻幼苗上仅引起罕见的病变。除侵染植物外，CHS1和CHS7还分别在分生孢子发生和附着胞形成过程中发挥特异性作用。有趣的是，chs7突变体在附着胞形成中被人工疏水表面上的芽管阻断，但在菌丝尖端和植物表面上是正常的。不同的几丁质合成酶基因可能参与了不同真菌组织或不同表面的附着胞形成过程。米。
Chitin is a major component of fungal cell wall and is synthesized by chitin synthases (Chs). Plant pathogenic fungi normally have multiple chitin synthase genes. To determine their roles in development and pathogenesis, we functionally characterized all seven CHS genes in Magnaporthe oryzae. Three of them, CHS1, CHS6, and CHS7, were found to be important for plant infection. While the chs6 mutant was non-pathogenic, the chs1 and chs7 mutants were significantly reduced in virulence. CHS1 plays a specific role in conidiogenesis, an essential step for natural infection cycle. Most of chs1 conidia had no septum and spore tip mucilage. The chs6 mutant was reduced in hyphal growth and conidiation. It failed to penetrate and grow invasively in plant cells. The two MMD-containing chitin synthase genes, CHS5 and CHS6, have a similar expression pattern. Although deletion of CHS5 had no detectable phenotype, the chs5 chs6 double mutant had more severe defects than the chs6 mutant, indicating that they may have overlapping functions in maintaining polarized growth in vegetative and invasive hyphae. Unlike the other CHS genes, CHS7 has a unique function in appressorium formation. Although it was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces, the chs7 mutant still produced melanized appressoria by hyphal tips or on plant surfaces, indicating that chitin synthase genes have distinct impacts on appressorium formation by hyphal tip and germ tube. The chs7 mutant also was defective in appressorium penetration and invasive growth. Overall, our results indicate that individual CHS genes play diverse roles in hyphal growth, conidiogenesis, appressorium development, and pathogenesis in M. oryzae, and provided potential new leads in the control of this devastating pathogen by targeting specific chitin synthases. Chitin is one of the major components of cell wall that plays vital roles in hyphal tip growth and fungal morphogenesis. Biosynthesis of chitin is catalyzed by chitin synthases, a well-known fungicide target. However, systematic characterization of chitin synthase genes has not yet been reported in plant pathogenic ascomycetes. To determine their roles in development and pathogenesis, in this study we functionally characterized all the seven chitin synthase genes (CHS1-CHS7) in Magnaporthe oryzae, a model for studying fungal development and pathogenesis. While CHS2, CHS3, CHS4, and CHS5 are dispensable for plant infection, CHS6 is essential for pathogenesis. The chs6 mutant failed to penetrate plant cells and develop infectious hyphae. Two other chitin synthase genes, CHS1 and CHS7, also are important for virulence. The chs1 and chs7 mutants caused only rare lesions on rice seedlings. Other than plant infection, CHS1 and CHS7 also play specific roles during conidiogenesis and appressorium formation, respectively. Interestingly, the chs7 mutant was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces but was normal by hyphal tips and on plant surfaces. Different chitin synthase genes may be involved during appressorium formation by different fungal tissues or on different surfaces in M. oryzae.
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影响因子：
2.9
作者：
Horiuchi, Hiroyuki
通讯作者：
Horiuchi, Hiroyuki
影响因子：
6.7
作者：
Huang K;Czymmek KJ;Caplan JL;Sweigard JA;Donofrio NM
通讯作者：
Donofrio NM
影响因子：
11.6
作者：
Ding, Sheng-Li;Liu, Wende;Xu, Jin-Rong
通讯作者：
Xu, Jin-Rong
DOI：
10.1007/bf02173007
发表时间：
1996-09-25
期刊：
MOLECULAR & GENERAL GENETICS
影响因子：
--
作者：
Ford, RA;Shaw, JA;Cabib, E
通讯作者：
Cabib, E
影响因子：
1.8
作者：
Kang, ZS;Zingen-Sell, I;Buchenauer, H
通讯作者：
Buchenauer, H