Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Workshop: Edible Legumes
The yield of the third-most important pulse crop chickpea (Cicer arietinum L.) is severely reduced by mainly two fungal pathogens, Ascochyta rabiei and Fusarium oxysporum f.sp. ciceri. Consequently chickpea research is aiming at the isolation of genes determining resistance towards these major pathogens. We have selected two different strategies for the identification of DNA markers and candidate resistance gene sequences linked to Fusarium resistance. First, several marker technologies such as DNA amplification fingerprinting (DAF) in combination with bulk segregant analysis (BSA) were employed to identify linked markers in an interspecific cross (C. arietinum x C. reticulatum) segregating for three race-specific Fusarium resistance genes (4, 5, and 0). Markers tightly linked to foc4 and foc5 were cloned and sequenced, with some of the polymorphic loci encoding specific domains of proteins such as leucine-rich repeats (LRR). Second, 37 candidate resistance genes were isolated using synthetic oligonucleotides as PCR primers targeting at conserved motifs of well-known R genes. A total of 23 different RGAs with typical sequence features of nucleotide–binding sites (NBS) were identified using different primer combinations on genomic DNA or cDNA as templates. Moreover, 12 different serine/threonine kinases, LRRs as well as chickpea homologs to the mlo gene of barley were identified. The mapping of candidate resistance genes as well as their representation in a BAC library will be presented. This work was supported by research grants no. Ka332/17-2 and 17-3 from the "Deutsche Forschungsgemeinschaft" (DFG).