Characterization of Pseudomonas syringae pv. syringae, the causal agent of bacterial blight of wheat in Kerman province and evaluation of the reaction of Iranian wheat genotypes to it

Wheat (Triticum aestivum) is the most important food crop in the world, but its yield is adversely affected due to plant pathogens particularly bacterial leaf blight (BLB) caused by Pseudomonas syringae pv. syringae (Pss). The management method presently in practice is insufficient to meet current safety and/or efficacy standards. Therefore, use of resistant genotypes is the best approach to manage BLB. The present study was undertaken to identify possible sources of resistance to Pss in cultivars and germplasms of wheat available. Two strains of Pss were isolated from symptomatic leaves of wheat and barley in Kerman province. The isolates were identified as Pss on the basis of physiological and biochemical characters, using specific primers and sequencing of 16S rRNA, ITS, and gyrB, rpoD, hrpL genes. Pss strains produced necrotic streaks on the susceptible wheat cv. Golestan. These strains were used for inoculation of 99 winter and spring wheat and durum (Triticum durum) genotypes to identify possible sources of resistance to BLB. The reaction of infiltrated seedlings fourth leaves infiltrated with bacterial suspension was scored seven to ten days after inoculation. Accessions were arranged in a randomized complete block design and three replications and five plants in each replicate were used. Among all the genotypes evaluated, only cv. Omid was found to be resistant to BLB. This wheat genotype can potentially be used in breeding wheat cultivars for resistance to BLB.