Genetic architecture of charcoal rot (Macrophomina phaseolina) resistance in soybean revealed using a diverse panel

Authors: COSER, SARA - Iowa State University; REDDY, CHOWDA - Iowa State University; ZHANG, JIAOPING - Iowa State University; MUELLER, DAREN - University Of Tennessee; Mengistu, Alemu; WISE, ALANE - Iowa State University; ALLEN, TOM - Iowa State University; SINGH, ARTI - Iowa State University; SINGH, ASHEESH - Iowa State University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2017
Publication Date: 9/21/2017
Citation: Coser, S., Reddy, C., Zhang, J., Mueller, D., Mengistu, A., Wise, A., Allen, T., Singh, A., Singh, A. 2017. Genetic architecture of charcoal rot (Macrophomina phaseolina) resistance in soybean revealed using a diverse panel. Frontiers in Plant Science. 8:1-12. https://doi.org/10.3389/fpls.2017.01626.
DOI: https://doi.org/10.3389/fpls.2017.01626

Interpretive Summary: Charcoal rot of soybean is a pervasive disease responsible for significant yield losses in soybean production. Among the methodologies available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association studies enable the identification of resistance. The objective of this study was to identify new sources of resistance to charcoal rot in a collection of 459 diverse plant introductions from the United States Department of Agriculture Soybean Germplasm Core Collection and identify candidate genes and associated molecular markers. New sources for charcoal rot resistance were identified from both field and greenhouse screening from maturity groups I, II and III. Genome-wide association studies using field screening data identified five significant single nucleotide polymorphisms and candidate genes related to abiotic and biotic stress responses; while greenhouse screening revealed eight DNA regions associated with functions controlling plant defense response. No overlap of markers or genes was observed between field and greenhouse screenings suggesting that resistance to charcoal rot in soybean may vary in response to different environments. Our findings provide useful information for advancing breeding for charcoal rot resistance and for understanding the genetic mechanism of resistance.

Technical Abstract: Charcoal rot disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methodologies available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association (GWA) studies enable unravelling the genetic architecture of resistance and identification of causal genes. The aim of this study was to identify new sources of resistance to charcoal rot in a collection of 459 diverse plant introductions from the USDA Soybean Germplasm Core Collection using specialized field and greenhouse screenings and to conduct GWA studies to identify candidate genes and associated molecular markers. New sources for charcoal rot resistance were identified from both field and greenhouse screening from maturity groups I, II and III. Genome-wide association studies using field screening data identified five significant single nucleotide polymorphism (SNP) and candidate genes related to abiotic and biotic stress responses; while greenhouse screening revealed eight loci associated with eight candidate gene families, all associated with functions controlling plant defense response. No overlap of markers or genes was observed between field and greenhouse screenings suggesting a complex molecular mechanism underlying resistance to charcoal rot in soybean with varied response to different environments; but our findings provide useful information for advancing breeding for charcoal rot resistance as well as the genetic mechanism of resistance.