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A small Ustilago maydis effector acts as a novel adhesin for hyphal aggregation in plant tumors
Author(s) -
Fukada Fumi,
Rössel Nicole,
Münch Karin,
Glatter Timo,
Kahmann Regine
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17389
Subject(s) - ustilago , hypha , effector , biology , bacterial adhesin , mutant , spore , cell wall , microbiology and biotechnology , fungus , virulence , fungal protein , gene , botany , genetics
Summary The biotrophic basidiomycete fungus Ustilago maydis causes smut disease in maize. Hallmarks of the disease are characteristic large tumors in which dark pigmented spores are formed. Here, we functionally characterized a novel core effector lep1 ( late effector protein 1 ) which is highly expressed during tumor formation and contributes to virulence. We characterize lep1 mutants, localize the protein, determine phenotypic consequences upon deletion as well as constitutive expression, and analyze relationships with the repellent protein Rep1 and hydrophobins. In tumors, lep1 mutants show attenuated hyphal aggregation, fail to undergo massive late proliferation and produce only a few spores. Upon constitutive expression, cell aggregation is induced and the surface of filamentous colonies displays enhanced hydrophobicity. Lep1 is bound to the cell wall of biotrophic hyphae and associates with Rep1 when constitutively expressed in hyphae. We conclude that Lep1 acts as a novel kind of cell adhesin which functions together with other surface‐active proteins to allow proliferation of diploid hyphae as well as for induction of the morphological changes associated with spore formation.