Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2003
Publication Date: 8/15/2003
Citation: Luo, M., Lee, R.D., Liang, X.Q.,Guo, B.Z., Holbrook, C.C. 2003. Identification of transcripts in peanut cultivars resistance to late leaf spot Cercosporidium personatum [abstract]. American Peanut Research and Education Society. Paper No. 103. Interpretive Summary:
Technical Abstract: Two expressed sequence tag (EST) libraries for cultivated peanut were constructed using mRNA prepared from leaves of peanut line C34-24 (resistant to leaf spots and tomato spotted wilt virus) and immature pods of peanut line A13 (drought tolerance and lower preharvest aflatoxin contamination). We had selected 384 genes with most known function related with adversity tolerance for making microarray chips. Peanut genotype C34-24 as resistant line and Florunner as susceptible line were used for microarray analysis. Plants were grown in the greenhouse, and challenged by Cercosporidium personatum or not challenged as control. About 112 spots (about 56 genes) were found to be up-regulated in fungal challenged plants as shown by microarray analysis (Log2 ratio>1), and 33 genes with known functions were proteins in secondary metabolism, stress proteins, heat shock proteins, signaling components, control of transcription, defense response, and unclassified proteins. Top 20 genes with higher expressions were chosen for further analysis using real-time PCR, and five genes were unknown function. The real-time PCR analyses show: 1) the expressions of some genes in real-time PCR were similar to microarray analyses, including cell-autonomous heat shock cognate protein 7, glycosyltransferase family, calcium binding protein, allergen Arah3/Arah4, protein kinase ATN1, cytochrome P450, auxin-induced protein 10A5, glycosyl hydrolase family 19, glutathione S-transferase GST 8, and superoxide dismutase [Cu-Zn]; 2) some genes were not significantly different between C34-24 challenged by C. personatum and control, such as Bax inhibitor-1 like protein, hypothetical protein p85RF, leucine-rich repeat protein; 3) although some gene expressions were significantly different between plants challenged and control, no differences were found between resistant line C34-24 and susceptible line Florunner, such as calcium binding protein. The disagreement between microarray analysis and real-time PCR is mainly due to gene cross hybridization. Although microarray technique has been proved to be an efficient way to screen transcripts in high throughput, other methods should be used to validate the data from cDNA microarray.