RESUMO
Global chickpea production is restricted by ascochyta blight caused by the necrotrophic fungi ascochyta rabiei. Developing locally adapted disease-resistant cultivars is an economically and environmentally sustainable approach to combat this disease. However, the lack of genetic variability in cultivated chickpeas and breeder-friendly markers poses a significant challenge to ascochyta blight-resistant breeding efforts in chickpeas. In this study, we screened the mini-core germplasm of Cicer reticulatum against a local pathotype of ascochyta rabiei. A modified mini-dome screening approach resulted in the identification of five accessions showing a high level of resistance. The mean disease score of resistant accessions ranged between 1.75±0.3 and 2.88±0.4 compared to susceptible accessions, where the mean disease score ranged between 3.59±0.62 and 8.86±0.14. Genome-wide association analysis revealed a strong association on chromosome 5, explaining ~58% of the phenotypic variance. The underlying region contained two candidate genes (Cr_14190.1_v2 and Cr_14189.1_v2), characterization of which showed the presence of a DNA binding domain (cl28899 & cd18793) in Cr_14190.1_v2 and its orthologs in C. arietinum, whereas Cr_14190.1_v2 carried an additional N-terminal domain (cl31759). qPCR expression analysis in resistant and susceptible accessions revealed ~3 and ~110-fold higher transcript abundance for Cr_14189.1 and Cr_14190.1, respectively.
