Response of sorghum stalk pathogens to brown midrib plants and soluble phenolic extracts from near isogenic lines

Funnell-Harris, D.L. and O’Neill, P.M. and Sattler, S.E. and et al, . (2017) Response of sorghum stalk pathogens to brown midrib plants and soluble phenolic extracts from near isogenic lines. European Journal of Plant Pathology, 148 (4). pp. 941-953.

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Sorghum [Sorghum bicolor (L.) Moench] has drawn attention as potential feedstock for lignocellulosic biofuels production, and reducing lignin is one way to increase conversion efficiency. Little research has been previously conducted to assess the response of reduced lignin sorghum lines to the Fusarium stalk rot pathogens Fusarium verticillioides and Fusarium proliferatum and the charcoal rot pathogen, Macrophomina phaseolina. Loss of function mutations in either the Brown midrib (Bmr) 6 or 12 gene that both encode a monolignol biosynthetic enzyme in the pathway that produces subunits of the lignin polymer, results in reduced lignin content. Near-isogenic bmr6, bmr12, and bmr6 bmr12 lines had previously been developed, which were shown to have significantly reduced lignin content and increased levels of soluble phenolics. In the current study, these lines in two backgrounds were shown to not be more susceptible to F. verticillioides, F. proliferatum and M. phaseolina inoculations, and some bmr lines exhibited increased resistance to F. proliferatum and M. phaseolina, compared to wild-type lines. When the Fusarium stalk rot pathogen, Fusarium thapsinum, was grown on methanol soluble stalk extracts from bmr6 and wild-type plants, it grew significantly faster on medium with bmr6 extract than on wild-type extract or controls. This result suggested that factors other than soluble phenolics from the extract, such as cell wall bound phenolics or inducible defense compounds, contributed to increased resistance observed in bmr6 plants.

Item Type: Article
Uncontrolled Keywords: Fusariumstalk rot, Charcoal rot, Sorghum bicolor (L.)Moench, brown midrib, Phenolic metabolites, Bioenergy feedstocks
Author Affiliation: Wheat, Sorghum and Forage Research Unit (WSFRU), United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Department of Plant Pathology, University of Nebraska (UNL), Lincoln, NE 68583-0937, USA
Subjects: Plant Protection
Divisions: Sorghum
Depositing User: Mr B Krishnamurthy
Date Deposited: 17 Oct 2017 08:45
Last Modified: 17 Oct 2017 08:45
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