Different Chitin Synthase Genes Are Required for Various Developmental and Plant Infection Processes in the Rice Blast Fungus Magnaporthe oryzae

PLoS Pathogens

Wen-Sheng Zhao¹  You-Liang Peng²  Lin-Lu Qi²  Jun Yang²  Jin-Rong Xu³  Ling-An Kong³  Guo-Tian Li³  Yu-Jun Zhang³  Chen-Fang Wang³ 

[1] College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China;Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China;State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China

关键词: Appressoria;    Chitin;    Leaves;    Barley;    Rice;    Plant fungal pathogens;    Fungal genetics;    Rice blast fungus;   

DOI  :  10.1371/journal.ppat.1002526

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY