Cellular Tracking and Gene Profiling of Fusarium graminearum during Maize Stalk Rot Disease Development Elucidates Its Strategies in Confronting Phosphorus Limitation in the Host Apoplast

PLoS Pathogens

Yufeng Wang¹  Ting-Lu Yuan²  Dong Zhang²  Lei-Jie Jia²  Yan Zhang²  Juan He²  Yan Guo²  Wei-Hua Tang² 

[1] Department of Biology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas, United States of America;National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China

关键词: Maize;    Phosphates;    Wheat;    Gene expression;    Lipids;    Fungal diseases;    Fungal genetics;    Fusarium graminearum;   

DOI  :  10.1371/journal.ppat.1005485

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The ascomycete fungus Fusarium graminearum causes stalk rot in maize. We tracked this pathogen’s growth in wound-inoculated maize stalks using a fluorescence-labeled fungal isolate and observed that invasive hyphae grew intercellularly up to 24 h post inoculation, grew intra- and inter-cellularly between 36–48 h, and fully occupied invaded cells after 72 h. Using laser microdissection and microarray analysis, we profiled changes in global gene expression during pathogen growth inside pith tissues of maize stalk from 12 h to six days after inoculation and documented transcriptomic patterns that provide further insights into the infection process. Expression changes in transcripts encoding various plant cell wall degrading enzymes appeared to correlate with inter- and intracellular hyphal growth. Genes associated with 36 secondary metabolite biosynthesis clusters were expressed. Expression of several F. graminearum genes potentially involved in mobilization of the storage lipid triacylglycerol and phosphorus-free lipid biosynthesis were induced during early infection time points, and deletion of these genes caused reduction of virulence in maize stalk. Furthermore, we demonstrated that the F. graminearum betaine lipid synthase 1 (BTA1) gene was necessary and sufficient for production of phosphorus-free membrane lipids, and that deletion of BTA1 interfered with F. graminearum’s ability to advance intercellularly. We conclude that F. graminearum produces phosphorus-free membrane lipids to adapt to a phosphate-limited extracellular microenvironment during early stages of its invasion of maize stalk.

【 授权许可】

CC BY