Plant genomics in lentil breeding: development of a cDNA-based rapid screening method for Ascochyta blight resistance in lentil (Lens culinaris L.)

Abstract

Non-Peer ReviewedAscochyta blight causes severe crop losses in temperate lentil production areas around the world, including Saskatchewan. At present there is no reliable system available to breeders for identifying blight resistant lentil lines. We are trying to develop a reliable, high throughput and low cost cDNA based system for screening lentil germplasm for polygenic resistance to Ascochyta blight. We have chosen the Ascochyta blight susceptible lentil variety Richlea and the closely related resistant breeding line 1156-2-17A for this study. Lentil plants were inoculated with spore suspensions of Ascochyta under conditions that clearly showed the difference in disease resistance between these lines. Tissue collected from resistant and susceptible lines at different times after inoculation will be used for extraction of total RNA–representing all the genes expressed by the plants in response to Ascochyta infection. Complementary DNA (cDNA) made from these RNA samples along with mock-inoculated controls will be visualized on poly acrylamide gels using the technique of ‘differential display’. We intend to identify the sequences of lentil genes expressed only by the resistant lines in response to Ascochyta infection and use them for developing molecular markers for the resistance trait. cDNA samples made from these plants will also be useful in developing a cDNA library of lentil tissue for future EST projects