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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCING CORN WITH RESISTANCE TO AFLATOXIN CONTAMINATION AND INSECT DAMAGE Title: Proteomic analysis of the maize rachis: Potential roles of constitutive and induced proteins in resistance to Aspergillus flavus and aflatoxin

Authors
item Pechanova, Olga -
item Techan, Tibor -
item Williams, William
item Luthe, Dawn -

Submitted to: Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 2010
Publication Date: January 1, 2011
Citation: Pechanova, O., Techan, T., Williams, W.P., Luthe, D.S. 2011. Proteomic analysis of the maize rachis: Potential roles of constitutive and induced proteins in resistance to Aspergillus flavus and aflatoxin. Proteomics. 11:114-127.

Interpretive Summary: Infection of the corn by the fungus Aspergillus flavus and the subsequent accumulation of the carcinogen aflatoxin in the grain is a persistent and serious agricultural problem causing disease and significant crop losses worldwide. The cob is an important structure of an ear of corn that delivers essential nutrients to the developing kernels and A. flavus spreads through the cob to infect kernels within the ear. The cob could play an important role in fungal proliferation and subsequent kernel contamination. We used proteomic approaches and investigated the cob tissue from aflatoxin accumulation resistant (Mp313E, Mp420) and susceptible (B73, SC212m) corn inbred lines. We compared proteins from cobs of resistant and susceptible inbred lines. The developing cobs of resistant lines contained higher levels of abiotic stress-related proteins and proteins from phenylpropanoid metabolism, whereas the cobs of susceptible lines exhibited pathogenesis-related proteins. We identified A. flavus-responsive proteins in cobs of both resistant and susceptible lines 10 and 35-days after infection. The differences in expression of proteins in the cobs of resistant and susceptible inbred lines could be used in identifying molecular markers that would be useful in developing corn hybrids with resistance to aflatoxin accumulation.

Technical Abstract: Infection of the maize (Zea mays L.) with aflatoxigenic fungus Aspergillus flavus and consequent contamination with carcinogenic aflatoxin is a persistent and serious agricultural problem causing disease and significant crop losses worldwide. The rachis (cob) is an important structure of maize ear that delivers essential nutrients to the developing kernels and A. flavus spreads through the rachis to infect kernels within the ear. Therefore, rachis plays an important role in fungal proliferation and subsequent kernel contamination. We used proteomic approaches and investigated the rachis tissue from aflatoxin accumulation resistant (Mp313E, Mp420) and susceptible (B73, SC212m) maize inbred lines. First, we compared rachis proteins from resistant and susceptible inbred lines, which revealed that the young resistant rachis contains higher levels of abiotic stress-related proteins and proteins from phenylpropanoid metabolism, whereas susceptible young rachis contains pathogenesis-related proteins, which are generally inducible upon biotic stress. Second, we identified A. flavus-responsive proteins in rachis of both resistant and susceptible genotypes after 10 and 35-day infections. Differential expression of many stress/defense proteins during rachis juvenility, maturation, and after A. flavus challenge demonstrates that resistant rachis relies on constitutive defenses which susceptible rachis is more dependent on inducible defenses.

Last Modified: 12/26/2014
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