1a.Objectives (from AD-416)
Develop soybean with broad resistance to all pests and pathogens using genetics and functional genomics. Special emphasis will be placed upon resistance to fungi and nematodes, as these are the main pests of soybean.
1b.Approach (from AD-416)
There is extensive knowledge of plant defense pathways leading to resistance to a multitude of pathogens, including fungi and bacteria, in the model system Arabidopsis. Especially important are the genes leading to the synthesis of jasmonate-related compounds, salicylic acid, ethylene and genes involve in the hypersensitive response. We propose to move the knowledge of disease resistance obtained using Arabidopsis into soybean to develop soybean with superior resistance to pests and pathogens, especially to fungi and nematodes, the primary biotic causes of yield loss. Over a multi-year period, we propose to identify more than fifty soybean genes homologous to Arabidopsis genes important to defense through comparison of DNA sequences and translated protein sequences, complementation of Arabidopsis mutants, and silencing of the homologous soybean genes.
We obtained more than twenty mutations in genes of the experimental plant Arabidopsis. We have found the genes in soybean that correspond to each of the mutated Arabidopsis genes. We will insert (genetically transform) the corresponding soybean gene into the mutant Arabidopsis plants. Some of the Arabidopsis mutants were planted and their mutations will be validated using a molecular assay to check the mutant. Twenty-two soybean genes with close DNA sequence identity to Arabidopsis genes of interest were cloned and their DNA sequence was determined to confirm their identity. Then they were prepared in a form that will allow them to be inserted into plants. These clones will be inserted into experimental Arabidopsis plants that carry mutations in the gene that correspond to the soybean gene. We then will be able to determine if the inserted soybean gene “corrects” the mutation and allows the mutant Arabidopsis plant to become normal. So far, we have inserted soybean genes into three Arabidopsis mutants with constructs containing the corresponding soybean genes. First generation seeds were collected and selected for further analysis. Information generated by this research will provide insight into new approaches to make soybeans resistant to pathogens which is the goal of the parent project.