Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/1998
Publication Date: N/A
Interpretive Summary: Molecular markers have become important tools for genetic analyses of crop species and for locating important genes in the plant genome. In this study, we used a relatively new class of marker system that identifies sequence repeats in the chickpea genome. The marker system called inter- simple-sequence-repeat (ISSR) was used in chickpea to locate the genes for resistance to fusarium wilt, a devastating vascular disease. By knowing th location of the resistance genes we were able to identify closely linked markers that can be used to efficiently select for disease resistant individuals in a breeding population. The knowledge gained will make it possible to improve chickpea germplasm for fusarium wilt resistance and also provide information on the chickpea genome.
Technical Abstract: We describe a simple and new approach, based on inter-simple sequence repeats (ISSRs), for finding markers linked to clusters of disease resistance genes. In this approach, simple sequence repeats(SSR) are used directly in PCR reactions, and markers found to be linked to disease resistance genes provide important information for the selection of other sequences which can be used with PCR to find other linked markers. Based on an ISSR marker linked to a gene of interest, many new markers can be identified in the same region. We previously demonstrated that ISSR markers are useful in gene tagging and identified a marker, UBC-855 500 , linked to the gene for resistance to fusarium wilt race 4 in chickpea. This ISSR marker provided the information used in the present study for selecting other primers which amplified a region linked the gene for resistance to fusarium wilt race 4. The primers were based on homology with the (AC)n sequence and were used for PCR amplifications. Changes in the sequence were at the anchor region of the primers. The repeat (AC)8T amplified a marker, UBC-825 1200, which was located 5.0 cM from the gene for resistance to fusarium wilt race 4 and was closer than other markers. These results indicated that ISSR markers can provide important information for the design of other primers and that by making changes at the 3' and 5' anchors close linkage to the desired gene can be found. The approach allows rapid scanning of the targeted region and may provide important information for genome analysis of plant species.