(500-11) Identification of potential Auxin Response Candidate genes for soybean rapid canopy coverage through comparative evolution and expression analysis
Body of Abstract: Glycine max, is one of the most cultivated crops worldwide, and the second largest crop produced in the U.S. A great effort has been made over the decades to improve soybean production in both traditional and organic agriculture, due to increased demand for soybean-based products for both sectors. Rapid canopy cover (RCC) development is effective in early season weed suppression and increases soybean yields, particularly in organic production conditions, where weeds may outcompete soybean seedlings.
While genome-wide association studies have identified some natural variants associated with RCC development, causal mechanisms have not been fully resolved. Here we focus on the use of genomic tools to identify genes involved in the auxin signaling pathway, which has been implicated in previous studies. Auxin modulates various aspects of plant development including response to light, organ patterning and expansion, and apical growth. Editing of auxin regulatory genes may enhance RCC development. To further define potential auxin signaling candidate genes for RCC we examined G. max genome sequences and compared them with the well characterized genes from Arabidopsis thaliana and examined the expression of these genes in an existing tissue level transcriptome dataset.
We identified 15 TIR1/AFB auxin co-receptors, 53 ARFs - auxin response factors, and 70 aux/IAA nuclear proteins in G. max. We compared the selected gene families against A. thaliana using Bayesian phylogenetic inference to identify orthologs in soybeans of genes associated with rosette area and branching in A. thaliana. We also examined existing gene expression datasets to identify auxin signaling genes highly expressed across different apical tissues early in development. We hypothesize that these genes will have a greater impact in canopy cover, and in future work will examine the functional effects of variants in our predicted canopy-cover-associated genes on auxin signaling and plant phenotype to identify breeding and gene editing targets.