title: Saccharomyces cerevisiae SSD1 orthologues are essential for host infection by the ascomycete plant pathogens Colletotrichum lagenarium and Magnaporthe grisea.
abstract: Fungal plant pathogens have evolved diverse strategies to overcome the multilayered plant defence responses that confront them upon host invasion. Here we show that pathogenicity of the cucumber anthracnose fungus, Colletotrichum lagenarium, and the rice blast fungus, Magnaporthe grisea, requires a gene orthologous to Saccharomyces cerevisiae SSD1, a regulator of cell wall assembly. Screening for C. lagenarium insertional mutants deficient in pathogenicity led to the identification of ClaSSD1. Following targeted gene replacement, appressoria of classd1 mutants retained the potential for penetration but were unable to penetrate into host epidermal cells. Transmission electron microscopy suggested that appressorial penetration by classd1 mutants was restricted by plant cell wall-associated defence responses, which were observed less frequently with the wild-type strain. Interestingly, on non-host onion epidermis classd1 mutants induced papilla formation faster and more abundantly than the wild type. Similarly, colonization of rice leaves by M. grisea was severely reduced after deletion of the orthologous MgSSD1 gene and attempted infection by the mutants was accompanied by the accumulation of reactive oxygen species within the host cell. These results suggest that appropriate assembly of the fungal cell wall as regulated by SSD1 allows these pathogens to establish infection by avoiding the induction of host defence responses.
authors.affiliation: Laboratory of Plant Pathology, Graduate school of Agriculture, Kyoto Prefectural University, Kyoto 606-8522, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Tanaka
authors.forename: Kaori
authors.initials: K
authors.lastname: Yamada
authors.forename: Kayo
authors.initials: K
authors.lastname: Yabumoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.forename: Aurélie
authors.initials: A
authors.lastname: Huser
authors.forename: Gento
authors.initials: G
authors.lastname: Tsuji
authors.forename: Hironori
authors.initials: H
authors.lastname: Koga
authors.forename: Koji
authors.initials: K
authors.lastname: Dohi
authors.forename: Masashi
authors.initials: M
authors.lastname: Mori
authors.forename: Tomonori
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Richard
authors.initials: R
authors.lastname: O'Connell
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kubo
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000648:ultrastructure; D020231:Colletotrichum / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000648:ultrastructure; D015966:Gene Expression Regulation, Fungal; D020043:Genes, Essential; D005816:Genetic Complementation Test; D020082:Magnaporthe / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; C485219:Ssd1 protein, S cerevisiae