Differential expression of signaling pathway genes associated with aflatoxin reduction quantitative trait loci in maize (Zea mays L.)

Authors: PARISH, FELICIA - Mississippi State University; Williams, William; Windham, Gary; SHAN, XUEYAN - Mississippi State University

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2019
Publication Date: 11/26/2019
Citation: Parish, F., Williams, W.P., Windham, G.L., Shan, X. 2019. Differential expression of signaling pathway genes associated with aflatoxin reduction quantitative trait loci in maize (Zea mays L.). Frontiers in Microbiology. 10(2683):1-10. https://doi.org/10.3389/fmicb.2019.02683.
DOI: https://doi.org/10.3389/fmicb.2019.02683

Interpretive Summary: The accumulation of aflatoxin, a toxin produced by the fungus Aspergillus flavus, in corn grain is a major food and feed safety problem in the southern United States. USDA-ARS at Mississippi State has developed corn germplasm with genetic resistance to aflatoxin accumulation. In this study, the roles of signaling pathway genes related to the aflatoxin reduction trait in corn were investigated: 55 genes in plant-pathogen interaction signaling pathways were investigated in 12 near-isogenic lines of corn with different combinations of four quantitative trait loci associated with aflatoxin reduction. These maize lines were developed from a cross between corn germplasm lines Mp313E (resistant donor parent) and Va35 (susceptible recurrent parent). Seven calcium-dependent protein kinases and one respiratory burst oxidase displayed significant differential expression levels among the lines. In addition, the gene expression profiles of transcription factors were examined, and expression for the WRKY 52, WRKY 71, and WRKY83 genes differed eamong the lines. The elucidation of differentially expressed signaling pathway genes associated with resistance provides insight into disease resistance of corn and enhances molecular breeding. This will expedite the development of corn hybrids with genetic resistance to aflatoxin accumulation and superior agronomic qualities.

Technical Abstract: The roles of signaling pathway genes related to the aflatoxin reduction trait in maize were studied for the improvement of maize resistance to the fungal pathogen Aspergillus flavus (A. flavus). In this study, 55 maize genes in plant-pathogen interaction signaling pathways were investigated among 12 maize near-isogenic lines (NILs) that carry maize quantitative trait loci (QTL) associated with aflatoxin reduction. These maize NILs were developed from maize inbred lines Mp313E (resistant donor parent) and Va35 (susceptible recurrent parent). The quantitative RT-PCR (qRT-PCR) technique was used to study the gene expression patterns. Seven calcium-dependent protein kinases and one respiratory burst oxidase displayed significant differential expression levels among the maize QTL-NILs. In addition, the gene expression profiles of WRKY transcription factors were also examined. Maize WRKY 52, WRKY 71, and WRKY83 genes displayed significantly differential expression levels among the QTL-NILs. The elucidation of differentially expressed signaling pathway genes involving maize resistance to A. flavus can provide insights into maize disease resistance and enhance maize molecular breeding. Keywords: signaling pathway genes, maize, Aspergillus flavus, aflatoxin reduction, Quantitative trait loci