Open AccessThe putative monomeric G‐protein GBP1 is negatively associated with fumonisin B 1 production in Fusarium verticillioides
Author(s) -
SAGARAM UMA SHANKAR,
BUTCHKO ROBERT A. E.,
SHIM WONBO
Publication year - 2006
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/j.1364-3703.2006.00347.x
Subject(s) - fusarium , fumonisin , biology , fumonisin b1 , mycotoxin , botany
SUMMARY Fumonisin B 1 (FB 1 ) is a mycotoxin produced by Fusarium verticillioides that contaminates maize. FB 1 has been linked to a number of human and animal mycotoxicoses worldwide. Despite its significance, our understanding of the FB 1 biosynthesis regulatory mechanisms is limited. Here, we describe F. verticillioides GBP1 , encoding a monomeric G‐protein, and its role in FB 1 biosynthesis. GBP1 was discovered as an expressed sequence tag (EST) up‐regulated in the F. verticillioides fcc1 mutant that showed reduced conidiation and no FB 1 biosynthesis when grown on maize kernels. Sequence analysis showed that GBP1 encodes a putative 368‐amino‐acid protein with similarity to DRG and Obg subclasses of G‐proteins that are involved in development and stress responses. A GBP1 knockout mutant ( Δgbp1 ) exhibited normal growth, but increased FB 1 production (> 58%) compared with the wild‐type when grown on corn kernels. Complementation of Δgbp1 with the wild‐type GBP1 gene restored FB 1 production levels to that of the wild‐type. Our data indicate that GBP1 is negatively associated with FB 1 biosynthesis but not with conidiation in F. verticillioides . The deletion of GBP1 led to up‐regulation of key FB 1 biosynthetic genes, FUM1 and FUM8 , suggesting that the increased FB 1 production in Δgbp1 is due to over‐expression of FUM genes.