Location: Soybean Genomics & Improvement Laboratory
2018 Annual Report
Objectives
Objective 1: Characterize biochemical processes in rust fungi and hosts during infection, determine relationships with currently used resistance genes, and work with breeders or pathologists to insert multiple resistance genes. [NP301, C1, PS1A; C3, PS3A]
Objective 2: Determine the role of root knot nematode secreted proteins in soybean growth alterations, such as the recently discovered MiIDL1 hormone mimic, to develop genetic resistance to the nematode. [NP301, C3, PS3A]
Objective 3: Assess proteins and metabolite profiles in soybean seeds, determine associations of metabolic pathways with nutritional traits, and identify germplasm or genes that breeders can use for genetic improvement of quality traits. [NP301, C2, PS2A]
Approach
For Objective 1, candidate rust fungus effector proteins identified in infected beans and soybeans will be characterized. A plant virus gene silencing system will be used to deliver fungal effector gene silencing RNAs from the plant to the fungus to block rust fungus infection. The fungal effector genes will be inserted into a plant virus for protein expression in plant leaves, and mass spectrometry will be used to identify plant proteins that interact with the fungal protein. Plants will be treated with plant hormones to induce disease resistance, and mass spectrometry will be used to identify plant proteins that contribute to disease resistance. Transgenic plants expressing proteins that may confer resistance to rust fungi will be screened by mass spectrometry and tested for resistance. For Objective 2, immunocytochemistry on thin root-gall sections will be performed to determine if an effector protein from a nematode pathogenic to soybean is secreted into the plant. The nematode effector gene will be expressed in plant roots, and mass spectrometry will be used to identify plant proteins that interact with the nematode protein. RNA sequencing and mass spectrometry will be used to identify differential transcript and protein accumulation in the galls formed on nematode infected roots. For Objective 3, a systems approach will be used to identify the protein and metabolic pathways that produce protein, oil, and carbohydrate seed traits in soybeans and to ensure that allergens and anti-nutritional proteins do not exceed normal levels. Comparative genomic hybridization will be used to map gene deletions associated with traits. Seeds with high protein content will be investigated by mass spectrometry for changes in the protein profiles with special attention being paid to assure the presence of low amounts of allergens or high methionine content. Seeds selected for oil, carbohydrates, and other (isoflavones, amino acids) traits will be investigated for changes in the metabolite profiles and to identify mutants with low anti-nutritional compounds/high isoflavone content.
Progress Report
This is a new project initiated on March 28, 2018 carried over from project 8042-21220-232-00D which was terminated on March 27, 2018. For Objective 1, research was begun to clone genes from the bean rust fungus, Uromyces appendiculatus. These genes will be used in gene silencing and protein-protein interaction experiments planned for FY18. For Objective 3, research was begun to extract DNA from fast neutron mutant seeds for comparative genomic hybridization (CGH) experiments planned for FY18.
Accomplishments
