ARS | Publication request: Grain from sorghum plants impaired in lignin biosynthesis have reduced colonization by some Fusarium species

Submitted to: Fungal Genetics Conference/Asilomar
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2011
Publication Date: March 15, 2011
Citation: Funnell-Harris, D.L., French, R.C., Sattler, S.E., Pedersen, J.F. 2011. Grain from sorghum plants impaired in lignin biosynthesis have reduced colonization by some Fusarium species. Fungal Genetics Conference/Asilomar. Abstract presented at 26th Fungal Genetics Conference at Asilomar, Pacific Grove, CA, March 15-20, 2011.

Technical Abstract: Sorghum is commonly infected by multiple members of the Gibberella fujikuroi and Fusarium incarnatum-F. equiseti species complexes (GFSC and FIESC, respectively). We had developed reduced lignin sorghum lines, usable for bioenergy feedstock, by incorporating two mutations in genes in the lignin biosynthesis pathway: brown midrib (bmr) 6 and bmr12. Grain and leaf tissue from bmr and near-isogenic wild-type lines were screened for colonization by Fusarium. Isolates from air samples within and above sorghum fields also were collected. One FIESC genotype was absent from bmr12 grain while the pathogen Fusarium proliferatum, in the GFSC, was significantly reduced; both genotypes were common in bmr6 and wild-type grain and were readily detected in air samples. Fusarium thapsinum, another member of GFSC, was the most commonly isolated Fusarium from grain, and also infected leaves, but was detected in air at low levels compared with other Fusarium species that infect sorghum. To further delineate GFSC and FIESC genotypes, sequences from the histone 3 gene and internal transcribed spacer (ITS), spanning regions 1 and 2, also were analyzed. This work provided evidence that perturbing biosynthesis of lignin affects colonization of grain by some members of GFSC and FIESC. Evidence from this study also supported the hypothesis that F. thapsinum was highly specific to and virulent on sorghum, as previously proposed by Leslie and associates.