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ARS Home » Research » Publications at this Location » Publication #114255
Title: TRANSCRIPTIONAL AND PROTEOMIC STUDY OF MAIZE (TEX6 & B73) KERNEL SPECIFIC RESPONSES INDUCED BY ASPERGILLUS FLAVUS MILK STAGE INFECTION

Author
item JI, CHENG - UNIV IL, URBANA, IL
item Norton, Robert
item WHITE, DONALD - UNIV IL, URBANA, IL

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/16/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The inbred Tex6 has a high level of resistance to pre-harvest infection by Aspergillus flavus and to aflatoxin contamination. We have developed analyses to identify multiple resistance genes, which reveal transcriptional and proteomic changes in Tex6 and B73 (susceptible) kernels in response to Aspergillus flavus milk stage infection. First, a new method of wound inoculation of maize ears was applied to minimize contamination caused by other microbes. Second, a novel sampling method was applied. In this method, one grain borne on the paired spikelets was inoculated with spores of Aspergillus flavus. The untreated grain of the paired spikelets was then sampled to analyze differential and inducible changes at certain time intervials. Third, experimental conditions for PCR-aided mRNA differential display and direct cDNA screening were established. A total of 48 mRNA transcripts that were affected in the kernels in response to fungal infection was detected. Three of them were selected to generate molecular probes with 32P-dATP and to characterize the relevance to Tex6 kernel resistance. Fourth, expression arrays that consist of known plant defense factors and apoptosis-specific factors have been under construction. They are expected to reveal Tex6 resistance factors in detail. Fifth, 2D-PAGE was conducted to identify in detail protein changes associated with fungal infection. On 2D-gels with a pH range (3-9), ca. 200 protein spots were visible in protein extracts from maize empryos, of which 4 protein spots appeared to be induced or enhanced in Tex6 by the infection. The sequence identity of the protein spots that were present at a level of nanogram will be revealed with the MALDI-MS technology.