Location: Wheat, Sorghum and Forage ResearchTitle: Field response of near-isogenic brown midrib sorghum lines to Fusarium thapsinum and effects of controlled water deficit on stalk rot disease
Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/27/2018
Publication Date: 7/29/2018
Citation: Funnell-Harris, D.L., Oneill, P.M., Sattler, S.E. 2018. Field response of near-isogenic brown midrib sorghum lines to Fusarium thapsinum and effects of controlled water deficit on stalk rot disease. International Congress of Plant Pathology Abstracts and Proceedings. [abstract].In: Proceedings of International Congress of Plant Pathology, International Society for Plant Pathology/American Phytopathology Society, July 29-August 30, 2018, Boston, MA.
Technical Abstract: To increase digestibility of sorghum [Sorghum bicolor (L.) Moench] biomass for ruminant livestock and lignocellulosic biofuels production, near-isogenic brown midrib (bmr) lines, bmr6, bmr12 and bmr6 bmr12 double mutant in backgrounds RTx430 and Wheatland were developed. Compared with wild-type, bmr lines have reduced lignin, altered lignin composition and altered phenolic metabolite levels due to mutations in monolignol pathway genes whose products synthesize lignin subunits. In previous greenhouse assays, bmr lines were not more susceptible, or were more resistant, to Fusarium stalk rot caused by Fusarium thapsinum, compared to wild-type. This destructive disease can result in lodging under high temperature or drought conditions. To determine if greenhouse results applied to field environments, bmr and near-isogenic wild-type plants were inoculated with F. thapsinum at irrigated and dryland sites. Mean lesion lengths of most bmr lines were similar to wild-type; bmr6 bmr12 plants had smaller lesions than corresponding wild-type under irrigation (P=0.03). To assess F. thapsinum virulence under drought condition, wild-type plants were inoculated in the greenhouse with adequate or deficient water regimes. Mean lesion lengths were greater on water-stressed plants than those on plants adequately watered (P=0.01). Development of this screen provides a way to identify sorghum germplasm with increased resistance or tolerance to Fusarium stalk rot under drought conditions.