Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/28/2005
Publication Date: 3/16/2005
Citation: Guo, B., Holbrook, Jr., C. C., He, G., Culbreath, A., Kvien, C. 2005. Identification and characterization of molecular marker(s) associated with resistance to TSWV, leafspots, and aflatoxin contamination. In: Proceedings of the National Peanut Foundation Meeting, March 16, 2005, Washington, DC. Interpretive Summary:
Technical Abstract: In peanut production areas in the southeastern U.S., tomato spotted wilt virus disease caused by tomato spotted wilt tospovirus (TSWV) has become more prevalent and more severe. TSWV has become a major limiting factor for many peanut producers and control methods are limited. Both early (Cercospora arachidicola) and late (Cercosporidium personatum) leaf spot diseases are also among the worst foliar diseases of the cultivated peanut and the control is mainly depending on routing applications of chlorothalonil, either on a calendar or advisory schedule. Aflatoxin contamination is another great concern of peanut industries and consumers. Our strategy is to develop peanut cultivars with resistance to these diseases by using marker-assistant breeding and selection. We have been characterizing and developing DNA polymorphic markers associated with the resistant traits in peanut lines, and generating a segregating population to map/clone the resistant loci/gene(s). These RILs (recombinant inbred lines) for linkage map and QTL mapping will be available in 2006. The progress has been made (2005): 1. One segregating population has been made from the cross between Tiftrunner and GT-20 (a Spanish type), and the goal is to develop about 500 RILs (recombined inbred lines). 2. We have screened RAPD SSR markers and have found two RAPD markers showing polymorphism between TSWV between the resistance cultivars (0013 and 448A) and susceptible cultivars (GK7 and Coan). 3. Two PCR primers, Sw5-2 and Sw5-3, have been generated based on the sequences of TSWV resistant genes in pepper and tomato. These two primers have been used to amplify 448A genomic DNA and produced single band with molecular weight ca. 250bp and 900bp, respectively. 4. Over 2,000 ESTs have been sequenced from 2 cDNA libraries, Tiftrunner leaf tissues and 013 immature seeds. About 400 unigenes have been generated from these ESTs and used for microarray analysis. Over 40 EST-derived SSRs have been developed. 5. About 5,000 clones have been sequenced from SSR enriched genomic libraries, and total 278 SSR sequences have been deposited in GenBank. We have characterized 450 soybean SSRs in cultivated peanuts, GK7, Coan, 0013, and 448A. Total 87 SSRs have been able to amplify peanut genomic DNA. 6. Microarray analysis of gene expression associated with leaf spot disease, Aspergillus parasiticus infection and drought stress. Interesting transcripts have been identified.