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

fungi;plant disease;secondary metabolism;antifungal

Holmes, Robert A ; Steven Spiker, Committee Member,Margaret Daub, Committee Member,Gary Payne, Committee Co-Chair,Rebecca Boston, Committee Co-Chair,Holmes, Robert A ; Steven Spiker ; Committee Member ; Margaret Daub ; Committee Member ; Gary Payne ; Committee Co-Chair ; Rebecca Boston ; Committee Co-Chair

University:North Carolina State University

关键词: fungi;    plant disease;    secondary metabolism;    antifungal;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/3693/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Crop contamination with aflatoxins produced Aspergillus flavus andAspergillus parasiticus is a persistent problem. A review of the literature on compounds thatinhibit aflatoxin biosynthesis showed that many inhibitors are plant-derived and some may beamenable to pathway engineering for defense against aflatoxin contamination. Othercompounds showed promise as storage protectants. Inhibitors with different modes of actioncould be used in transcriptional and metabolomic profiling experiments to identify regulatorynetworks 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.