A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces

PLoS Pathogens

Alison Lovegrove¹  Matthew Evans¹  Amy Plummer¹  Robert King²  Nichola Hawkins³  Rebecca P. Lauder⁴  Kirstie Halsey⁴  Martin Urban⁵  Kim Hammond-Kosack⁵  Jason J. Rudd⁵ 

[1] Cereal cell walls group, Department of Plant Sciences, Rothamsted Research, Harpenden, Herts, United Kingdom;Department of Computational and Analytical Sciences, Rothamsted Research, Harpenden, Herts, United Kingdom;Fungicide resistance group, Department of BioInteractions and Crop Protection, Rothamsted Research, Harpenden, Herts, United Kingdom;Rothamsted Centre for Bioimaging, Department of Plant Sciences, Rothamsted Research, Harpenden, Herts, United Kingdom;Wheat Pathogenomics Team, Department of BioInteractions and Crop Protection, Rothamsted Research, Harpenden, Herts, United Kingdom

关键词: Fungal genetics;    Fungi;    Plant fungal pathogens;    Leaves;    Wheat;    Fungal genomics;    Fungal diseases;    Fungal spores;   

DOI  :  10.1371/journal.ppat.1006672

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast “yeast-like” growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices.

【 授权许可】

CC BY