Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2006
Publication Date: November 2, 2006
Citation: Guo, B., Luo, M., Liang, X.Q., Holbrook, Jr., C.C. 2006. Microarray gene expression analysis of peanut responding to drought stress and Aspergillus infection [abstract]. In: Proceedings of the International Conference on Groundnut Aflatoxin Management and Genomics, November 5-9, 2006, Guangzhou, China. P. 41. Technical Abstract: Aflatoxin contamination caused by Aspergillus fungi is a great concern in peanut production worldwide. Pre-harvest A. parasiticus infection and aflatoxin contamination are usually severe in peanuts that are grown under drought stressed conditions; however, drought tolerant peanut lines have less aflatoxin contamination. The objective of this study was to develop peanut seed EST database as a resource for a functional genomic tool-microarray to study gene expression and to identify resistance genes in response to A. parasiticus infection. In this report we present gene expression profiles using a cDNA microarray of peanut in responding to A. parasiticus infection and drought stress. The microarray data were re-evaluated by quantitative real-time PCR. Peanut genotype A13 which is drought tolerant with reduced aflatoxin contamination was used in this study. The cDNA microarray was spotted twice on the glass slides of each of the selected unigenes (384 unigenes) selected from two Expressed Sequenced Tag (EST) cDNA libraries challenged by biotic and abiotic stresses. A total of 42 up-regulated genes (Log2 ratio>1) in several functional categories were detected under both A. parasiticus challenge and drought stress. A total of 52 up-regulated genes were detected in response to drought stress alone. There were 25 genes commonly expressed in both treatments. The top 20 up-regulated gene from A. parasiticus challenge and drought stress were selected for validation of their expression levels using real-time PCR. A13 was also used to study the functional analysis of these genes and a possible link of these genes to the resistance trait. Although the spotted cDNA array had a small set of genes, it demonstrated the power and utility in functional global gene expression overview. Therefore, much more ESTs are needed for peanut research community internationally in order to have enough putative genes for genomic analysis.