Gene Expression Analysis of some Resistance Genes in Ascochyta Blight Infected Chickpea (Cicer arietinum)

The fungal disease, ascochyta blight, caused by Ascochyta rabiei is a major yield-limiting factor of chickpea (Cicer arietinum L.) around the world. A clear understanding of the chickpea defense mechanism against A. rabiei is very important for breeding resistant cultivars and better management of this fungal disease. Induced resistance to a pathogen is one of the ways which plants use against biotic stresses. This study was conducted in 2018 as a two-factor factorial experiment (time-genotype) in a completely randomized design with three replications for each of the selected times and the control plant in the laboratory of the Plant Breeding Department of the Faculty of Agriculture, University of Mohaghegh Ardabili. In this study, AFP-ca, Protein with leucine zipper, Snakin2, and PGIP genes were selected and plant responses to pathogen were studied in two susceptible and resistant genotypes. The experimental system was conducted in a greenhouse, for both inoculated and mock-inoculated plants a control plant with three technical replicates. RNA extractions from FLIP00-40C (resistant) and FLIP03-135C (sensitive) genotypes were performed using RNX-plus kit at 0, 6, 12, 24, 48, 72 and 96 hours post inoculation (hpi) and also for mock-inoculated plants. The expression of these genes after inoculation by Ascochyta rabiei was measured in susceptible and resistant plants via Real-Time PCR. The results showed an increase in the expression level of all genes studied in this research in resistant cultivar compared with susceptible cultivar. Results showed that the candidate gene from the antimicrobial family (AFP-ca) was upregulated in resistant cultivar at early hours after inoculation (6-24 hpi), and also for PGIP from galacturonase-inhibit protein family, the gene was maximally expressed to early hours of inoculation to 48 hpi. In general, it can be concluded that all genes studied in this research contribute to plant-pathogen interactions and all of them may increase the resistance response to Ascochyta blight disease.