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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #359880

Research Project: Use of Classical and Molecular Technologies for Developing Aflatoxin Resistance in Crops

Location: Food and Feed Safety Research

Title: Contribution of maize polyamine and amino acid metabolism towards resistance against Aspergillus flavus infection and aflatoxin production

item Majumdar, Raj
item MINOCHA, RAKESH - Us Forest Service (FS)
item Lebar, Matthew
item Rajasekaran, Kanniah - Rajah
item LONG, STEPHANIE - Us Forest Service (FS)
item Carter-Wientjes, Carol
item MINOCHA, SUBHASH - University Of New Hampshire
item Cary, Jeffrey

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/4/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Polyamines (PAs) are ubiquitous polycations found in plants and other organisms that are essential for growth, development, and resistance against abiotic and biotic stresses. The role of PAs in plant disease resistance depends on the relative abundance of higher PAs [spermidine (Spd), spermine (Spm)] vs. the diamine putrescine (Put) and PA catabolism. With respect to the pathogen, PAs are required to achieve successful pathogenesis of the host. Maize is an important food and feed crop, which is highly susceptible to A. flavus infection. Upon infection, the fungus produces carcinogenic aflatoxins and numerous other toxic secondary metabolites that adversely affect human health and crop value worldwide. To evaluate the role of PAs in aflatoxin resistance in maize, in vitro kernel infection assays were performed using maize lines that are susceptible (SC212) or resistant (TZAR102, MI82) to aflatoxin contamination. Results indicated significant induction of both PA biosynthetic and catabolic genes upon A. flavus infection. As compared to the susceptible line, the resistant maize lines showed higher basal expression of PA metabolism genes in mock-inoculated kernels that increased upon fungal infection. In general, increased biosynthesis and conversion of Put to Spd and Spm along with their increased catabolism was evident in the resistant lines vs. the susceptible line SC212. Higher accumulation of amino acids such as glutamate (Glu), glutamine (Gln), and '-aminobutyric acid (GABA) correlated with a significant increase in aflatoxin production in SC212. The resistant lines showed a significant reduction in fungal load and aflatoxin production compared to the susceptible line. The data presented here demonstrate an important role of PA metabolism in the resistance of maize to A. flavus colonization and aflatoxin contamination. These results provide future directions for the manipulation of PA metabolism and/or the use of Spd/Spm as biomarkers to screen maize genotypes for improved aflatoxin resistance and overall stress tolerance.