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United States Department of Agriculture

Agricultural Research Service

Title: Low Lignin (Brown Mid-rib) Sorghum Genotypes Restrict Growth of Fusarium Spp. as Compared with Near-Isogenic Wild-Type Sorghum

Authors
item Funnell-Harris, Deanna
item Pedersen, Jeffrey
item Sattler, Scott

Submitted to: American Pathological Society North Central Division Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 13, 2009
Publication Date: June 21, 2009
Citation: Funnell-Harris, D.L., Pedersen, J.F., Sattler, S.E. 2009. Low Lignin (Brown Mid-rib) Sorghum Genotypes Restrict Growth of Fusarium Spp. as Compared with Near-Isogenic Wild-Type Sorghum. Proceedings 2009 APS North Central Division, "Meeting the Challenges of Global Food & Energy Production" pg. 20.

Interpretive Summary: To increase usability of sorghum for bioenergy and forages, two different brown midrib (bmr) genes, bmr-6 and bmr-12, were backcrossed into five elite backgrounds, resulting in reduced lignin near-isogenic genotypes. Field-grown grain from bmr-6 and bmr-12 plants had significantly reduced colonization by Fusarium moniliforme sensu lato as compared with wild-type grain. Fusarium isolates were identified to species using sequence analysis of the translation elongation factor gene. Three of the most commonly identified species, Fusarium thapsinum, Fusarium proliferatum and Fusarium verticillioides, were members of F. moniliforme and include sorghum pathogens. Three other commonly isolated species, Fusarium bullatum, Fusarium pallidoroseum and Fusarium graminearum, likely colonize sorghum asymptomatically. Chi-square analyses showed that the ratios of Fusarium species colonizing bmr-12 grain were significantly different from those of wild-type, indicating that bmr-12 affects colonization by Fusarium spp. across genetic backgrounds. A thrice-replicated bioassay was conducted in which peduncles of wild-type and near-isogenic bmr genotypes in a single background were inoculated with fungi associated with sorghum. F. thapsinum, F. verticillioides, Fusarium armeniacum and Alternaria alternata were pathogenic on wild-type plants in most cases. Lesion lengths were significantly reduced on one or both bmr genotypes infected by F. verticillioides, F. thapsinum or A. alternata compared to lesions produced on near-isogenic wild-type plants. These data indicate that bmr-6 and bmr-12 affect colonization by Fusarium spp. and A. alternata.

Technical Abstract: To increase usability of sorghum for bioenergy and forages, two different brown midrib (bmr) genes, bmr-6 and bmr-12, were backcrossed into five elite backgrounds, resulting in reduced lignin near-isogenic genotypes. Field-grown grain from bmr-6 and bmr-12 plants had significantly reduced colonization by Fusarium moniliforme sensu lato as compared with wild-type grain. Fusarium isolates were identified to species using sequence analysis of the translation elongation factor gene. Three of the most commonly identified species, Fusarium thapsinum, Fusarium proliferatum and Fusarium verticillioides, were members of F. moniliforme and include sorghum pathogens. Three other commonly isolated species, Fusarium bullatum, Fusarium pallidoroseum and Fusarium graminearum, likely colonize sorghum asymptomatically. Chi-square analyses showed that the ratios of Fusarium species colonizing bmr-12 grain were significantly different from those of wild-type, indicating that bmr-12 affects colonization by Fusarium spp. across genetic backgrounds. A thrice-replicated bioassay was conducted in which peduncles of wild-type and near-isogenic bmr genotypes in a single background were inoculated with fungi associated with sorghum. F. thapsinum, F. verticillioides, Fusarium armeniacum and Alternaria alternata were pathogenic on wild-type plants in most cases. Lesion lengths were significantly reduced on one or both bmr genotypes infected by F. verticillioides, F. thapsinum or A. alternata compared to lesions produced on near-isogenic wild-type plants. These data indicate that bmr-6 and bmr-12 affect colonization by Fusarium spp. and A. alternata.

Last Modified: 10/26/2014
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