جداسازی و فراوانی باکتری‌های عامل سوختگی برگ و سیاه شدن پوشینه گندم و جو در استان چهارمحال و بختیاری

Bacterial leaf blight and black chaff is the most important disease of wheat and barley in fields with rain irrigation systems in Chaharmahal va Bakhtiary province, causing economic damage in cold regions. In 2015, a disease with symptoms of leaf blight and sometimes black chaff was observed in wheat and barley fields in Shahrekord region. Pseudomonas syringae pv lapsa (Psl) was isolated and identified from plants with such symptoms. The disease spread in the province in the following years, with similar symptoms reported in some cold regions of the country. In this research conducted between 2019-2024, the frequency of pathogenic bacteria associated with the disease was determined, along with investigating some biological and molecular characteristics of Psl as the dominant pathogen. From 226 samples of wheat and barley with suspected bacterial disease symptoms, strains of Psl (41.1%), Pseudomonas syringae pv syringae (15.5%), Pseudomonas syringae pv atrofaciens (12.8%), and Xanthomonas translucens pv undulosa (7%) were isolated and identified. Pathogenic bacteria were not isolated from 22.5% of the samples. The pathogenicity of the isolates was confirmed on wheat and barley plants grown in pots. This research confirms that Psl is the dominant pathogen causing symptoms of bacterial leaf blight and black chaff in wheat and barley fields with rain irrigation in Chaharmahal va Bakhtiary province. Managing the disease caused by Psl is crucial, and using certified and pathogen-free seed is recommended.