Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2005
Publication Date: June 30, 2005
Citation: Funnell, D., Pedersen, J.F. 2005. Evidence for increased resistance to Fusarium moniliforme sensu lato in sorghum genetically modified for reduced lignin content. Phytopathology. 95:S32 Technical Abstract: Two genes, bmr-6 and bmr-12, conferring the brown midrib (bmr) trait associated with reduced lignin, were backcrossed into five elite sorghum lines, resulting in near-isogenic lines with reduced lignin when compared with the wild-type. Seed and leaf tissue from field-grown plants of bmr and wild-type lines were screened for infection by Alternaria species and Fusarium species. Numbers of Alternaria species isolated from bmr lines were not significantly greater than those isolated from wild-type lines, suggesting that the bmr lines do not have increased susceptibility to colonization by Alternaria species. When fungal outgrowths from seed were selected on a Fusarium selection medium, significantly fewer seeds from bmr lines were infected with Fusarium moniliforme and other Fusarium species, suggesting that lines reduced in lignin might have increased resistance to colonization by F. moniliforme, at least in some genetic backgrounds. Further support was provided by greenhouse bioassays in which peduncles of developing heads were wound-inoculated with a F. moniliforme isolate pathogenic to sorghum. Mean lesion lengths on bmr plants were significantly less than those resulting from inoculations on wild-type plants. A possible mechanism for increased resistance in reduced lignin lines is discussed.