Reaction of Iranian Cereal Genotypes to Multiple St rains of Xanthomonas translucens pv. cerealis

Abstract

Bacterial leaf streak (BLS) caused by Xanthomonas translucens pv. cerealis ( Xtc ) is an important disease of wheat ( Triticum aestivum L.) worldwide. The management methods presently in practice are insufficient to meet curr ent safety and/or efficacy standards. Therefore, use of resistant genotypes is the best a pproach to manage BLS. The present study was undertaken to identify possible sources o f resistance to Xtc in cereal cultivars and germplasm. Twelve strains of Xtc were isolated from symptomatic leaves in several regions in Kerman province. Out of twelve, nine str ains produced the expected Xtc - specific 120 bp fragment using PCR and the primer p airs PABr/PBf. Six strains produced water-soaked streaks covered with exudates on wheat cultivars, whereas the three remaining strains incited only chlorotic streaks wi th no water-soaking on leaves. A highly virulent strain that caused conspicuous water-soaki ng and necrosis was used for inoculation of 645 winter and spring wheat, barley, and rye accessions to identify possible sources of resistance to BLS. The fourth leaves of test plants were infiltrated with bacterial suspension and scored after seven to ten days. Among all the accessions evaluated, only two rye accessions, namely, 4538 an d 4794, were resistant to BLS. These two rye accessions can potentially be used in breed ing rye and triticale cultivars for resistance to BLS. Keywords : Bacterial leaf streak, Barley, Resistance, Rye, W heat.