Diploid wheat (Triticum monococcum) as a model for gene discovery in wheat

The cultivated diploid, tetraploid and hexaploid wheat species provide advantages of diploid and polyploid genetic systems. Diploid wheat can facilitate gene discovery and, rules governing interactions among homoeoloci affecting transcription, translation and phenotypic expression can be analyzed in polyploid wheat. Towards this end we are developing a TILLING (Targeting Induced Local Lesions IN Genomes) resource in diploid wheat. We employed TILLING to characterize the role played by 9 important gene families of ligno-cellulose pathway in diploid wheat to determine the efficiency of TILLING based gene discovery in diploid wheat. Nine ligno-cellulose pathway genes HCT1, HCT2, PAL6, PAL8, 4CL1, CAD4, C3H, C4H1, CCoAMT3, CCR1, CCR2, CCR3, COMT1, F5H1 and F5H2 were investigated in TILLING population comprising of over 1700 individuals by standard TILLING procedure of hetero-duplex formation and Cel-I endonuclease digestion.  Gene specific primer pairs were designed from all ESTs corresponding to the selected genes for screening the 4x pools of the TILLING population. On an average 10 putative mutants were observed for each gene and were sequenced to identify SNPs. A total of 96 mutants were found for 10.9 mb of DNA scanned in the 1700 strong mutant population. The average mutation rate of 1/111 kb of exonic DNA screened found is higher than reported for other diploid plants.  The progress on TILLING in T. monococcum will be presented.