Location: Wheat, Sorghum and Forage Research
Project Number: 3042-21220-034-000-D
Project Type: In-House Appropriated
Start Date: Feb 6, 2023
End Date: Feb 5, 2028
Objective 1. Identify and manipulate the genetic and biochemical mechanisms controlling phenylpropanoid metabolism to develop improved sorghum germplasm for grain and biomass uses. Sub-objective 1.A: Develop sorghum impaired in chalcone isomerase (CHI) activity for grain and biomass uses. Sub-objective 1.B: Characterize the effects of brown midrib mutants (bmr) on phenylpropanoid metabolism and lignin composition for lignin valorization. Objective 2. Identify and manipulate the genetic and biochemical mechanisms controlling starch composition in grain to develop novel traits for food, feed, and renewable resources. Sub-objective 2.A: Identify and characterize mutants that increase amylose composition of starch. Sub-objective 2.B: Identify mechanisms to increase the starch composition of sorghum grain. Objective 3. Identify resistance to root and stalk fungal pathogens under abiotic stress conditions in sorghum germplasm. Sub-objective 3A: Identify seedling damping-off-resistant germplasm using high-throughput phenotyping. Sub-objective 3B: Evlauate the role of jasmonic acid in sorghum responses to Fusarium stalk rot and charcoal rot under adequate and deficit water conditions. Objective 4. Identify resistance to grain fungal pathogens in sorghum germplasm with novel phenylpropanoid and starch compositions. Sub-objective 4A: Determine effects of grain molds on bmr19 plants. Sub-objective 4B: Determine the stage when Fusarium grain mold pathogens infect developing grain and the effect of plant resistance. Subobjective 4C: Assess responses of grain mold pathogens to divergent starch concentrations.
Sorghum (Sorghum bicolor) is a climate resilient crop that provides grain and forage (biomass) to existing agricultural markets, but it has the potential to provide biomass to emerging renewable products markets in the United States. To compete in these markets, compositional improvements to both sorghum grain and forage are needed, as well as an understanding of how these changes affect the fungal pathogens of sorghum. The objectives of this project will focus on the genetic, biochemical, and physiological mechanisms affecting the composition of sorghum biomass and grain. Efforts will result in sorghum with altered lignin content and/or composition of biomass (Objective 1), and increased starch content and/or amylose content for human nutrition (Objective 2). The impacts of fungal pathogens on sorghum with compositionally modified biomass and grain will be determined. Seedling disease (“damping off”) resistance germplasm will be identified to augment sorghum resiliency by utilizing spring soil moisture (Objective 3). New sources of grain mold and stalk rot disease resistance will be examined (Objective 4). Sorghum germplasm with desirable traits enhancing sorghum biomass and grain utilization will be developed, fully characterized, released, and deposited into the USDA–ARS National Plant Germplasm System (NPGS) for use by public and private sector plant breeders for developing improved hybrids and cultivars. The project consists of three integrated components: germplasm development, molecular biology, and plant pathology. Molecular and conventional methodologies will be utilized, and the project scale will range from gene-level to field-level. The project also has extensive formal and informal collaborations enhancing our ability to conduct this research. Anticipated products include improved sorghum germplasm for the sorghum seed industry with value-added traits and biotic stress tolerance, and tools to assess these biological pathways and fungal pathogen responses of sorghum.