Characterization of an aflatoxin biosynthetic gene and resistance in maize seeds to Aspergillus flavus

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dc.contributor.advisor Steven Spiker, Committee Member en_US
dc.contributor.advisor Margaret Daub, Committee Member en_US
dc.contributor.advisor Gary Payne, Committee Co-Chair en_US
dc.contributor.advisor Rebecca Boston, Committee Co-Chair en_US Holmes, Robert A en_US 2010-04-02T18:34:44Z 2010-04-02T18:34:44Z 2008-10-20 en_US
dc.identifier.other etd-08182008-112539 en_US
dc.description.abstract Crop contamination with aflatoxins produced Aspergillus flavus and Aspergillus parasiticus is a persistent problem. A review of the literature on compounds that inhibit aflatoxin biosynthesis showed that many inhibitors are plant-derived and some may be amenable to pathway engineering for defense against aflatoxin contamination. Other compounds showed promise as storage protectants. Inhibitors with different modes of action could be used in transcriptional and metabolomic profiling experiments to identify regulatory networks controlling aflatoxin biosynthesis. Liquid chromatography was used to characterize a protein fraction from kernels of the resistant maize line Tex6 that inhibits growth and aflatoxin production by A. flavus in vitro. Two proteins were associated with the inhibitory activity. Peptide sequencing identified them as chitinase A (ChitA) and zeamatin, members of the glycoside hydrolase 19 (GH19) and thaumatin-like protein (TLP) families, respectively. Removal of chitin-binding proteins from the fraction dramatically reduced its inhibitory effect. Adding the chitin-binding fraction back to the zeamatin-enriched fraction restored activity. We used bioinformatic, phylogenetic and gene expression analyses to investigate the GH19 and TLP gene families in maize. Phylogenetic analyses placed the maize GH19 genes into four major phylogenetic groups. The TLP gene family was larger and was similar to the rice TLP family. Transcripts of members of each gene family were induced during A. flavus infection of kernels. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject fungi en_US
dc.subject plant disease en_US
dc.subject secondary metabolism en_US
dc.subject antifungal en_US
dc.title Characterization of an aflatoxin biosynthetic gene and resistance in maize seeds to Aspergillus flavus en_US PhD en_US dissertation en_US Plant Biology en_US

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