Submitted to: Euphytica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/23/2002
Publication Date: 11/1/2002
Citation: RAJESH, P.N., TEKEOGLU, M., GUPTA, V.S., RANJEKAR, P.K., MUEHLBAUER, F.J. MOLECULAR MAPPING AND CHARACTERIZATION OF AN RGA LOCUS RGSPTOKIN1-2 171 IN CHICKPEA. EUPHYTICA. 2002. v. 128. p. 427-433 Interpretive Summary: Several economically important diseases that include Fusarium wilt and Ascochyta blight affect Chickpea. In our research on the genetics of disease resistance we have identified DNA primers for resistance genes and used those primers to determine their presence in the chickpea progenies we are using. These primers are known as `resistance gene analogs¿ (RGAs) and are often associated with resistance to particular diseases in plants. Our results showed that one of the RGAs is located on the chickpea linkage map in the vicinity of a gene for resistance to Ascochyta blight. This result is the first step in identification of an important disease resistance gene in chickpea and toward clarifying its structure and mode of action. The results will improve our understanding of disease resistance genes in chickpea and further our efforts toward development of disease resistant varieties for use by producers.
Technical Abstract: Resistance gene analog polymorphism (RGAP) is a targeted homology based method, which has been used in different crops to identify tightly linked markers for disease resistance genes and also to enrich the map with a different class of markers. In chickpea, using the RGA primers, which are designed based on the conserved motifs present in characterized R-genes, Bulk Segregant Analysis (BSA) was preformed on a resistant bulk and a susceptible bulk along with parents for ascochyta blight resistance. Of all available RGAs and their 48 different combinations, only one RGA showed polymorphism during BSA. This marker was evaluated in an F7:8 population of 142 RILs from an interspecific cross of C. arietinum (FLIP 84-92C) x C. reticulatum (PI 599072) and was mapped to the Cicer linkage map. The genomic location of chickpea RGA was compared with the locations of mapped chickpea R-genes. This is the first RGA marker mapped to chickpea linkage map.