Submitted to: National American Phytopathology Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 5/3/2010
Publication Date: 6/1/2010
Citation: Funnell-Harris, D.L., Pedersen, J.F., Sattler, S.E. 2010. Alteration in Lignin Biosynthesis Restricts Growth of Fusarium Species in Brown Midrib Sorghum. Phytopathology 100:S37
Technical Abstract: To improve sorghum for bioenergy and forage uses, brown midrib6 (bmr6) and bmr12 near-isogenic genotypes were developed in different sorghum backgrounds. bmr6 and bmr12 grain had significantly reduced colonization by members of the Gibberella fujikuroi species complex, compared with wild-type, as detected on two semi-selective media. Fusarium species were identified using sequence analysis of a portion of the translation elongation factor 1-a gene (TEF). The pathogens Fusarium thapsinum, Fusarium proliferatum and Fusarium verticillioides, G. fujikuroi members, were commonly recovered. Other frequently isolated Fusarium species likely colonize sorghum asymptomatically. Chi-square analyses showed that the ratios of Fusarium species colonizing bmr12 grain were significantly different from wild-type, indicating that bmr12 affects colonization by Fusarium spp. One Fusarium incarnatum/equiseti species complex (FIESC) genotype, commonly isolated from wild-type and bmr6 grain, was not detected in bmr12 grain. Phylogenetic analysis suggested that this FIESC genotype represents a previously unreported TEF haplotype. When peduncles of wild-type and near-isogenic bmr plants were inoculated with F. thapsinum F. verticillioides, or Alternaria alternata, the resulting mean lesion lengths were significantly reduced relative to wild-type in one or both bmr mutants. This indicates that impairing lignin biosynthesis results in reduced colonization by Fusarium spp. and A. alternata.