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Double chitin synthetase mutants from the corn smut fungus Ustilago maydis
Author(s) -
CHAVEZONTIVEROS JEANETT,
MARTINEZESPINOZA ALFREDO D.,
RUIZHERRERA JOSE
Publication year - 2000
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 - 10.1046/j.1469-8137.2000.00635.x
Subject(s) - ustilago , chitin , biology , mutant , chitin synthase , mating type , gene , genetics , microbiology and biotechnology , biochemistry , botany , chitosan
Using genetic crosses between single chs mutants of Ustilago maydis inoculated into maize ( Zea mays ) seedlings, two classes of double mutants affected in genes coding for chitin synthetases were isolated: chs3 / chs4 , and chs4 / chs5 . Analysis of the mutants showed almost no change in their phenotype compared with wild‐type strains. Growth rate, effect of stress conditions, dimorphic transition and mating were not affected. The only salient differences were increased sensitivity to osmotics at acid pH, and decrease in chitin synthetase activity, especially when measured with CO 2+ , and in chitin content. Most significant was a decrease in virulence, although this appeared to be due a factor unrelated to CHS genes. These data can be taken as further evidence that multigenic control of chitin synthetase in fungi operates as a safety mechanism to guarantee fungal viability in changing and hostile environmental conditions.