گزارش وقوع بیماری پژمردگی باکتریایی لوبیا در استان لرستان

Bacterial wilt of beans or tan spot, is an important plant disease which threatens legume crops all over the world and Iran. This is the most destructive bacterial disease in Fabaceae family crops. Its losses from the first report in 1926, has been very important due to seedborne nature of bacterial pathogen by which can transfer far distances. According to lack of absolute control method, sanitation and quarantine procedures are recommended to seeds transportation. Because of variations in color of bacterial colony, morphological identification of pathogen is relatively difficult. Disease symptoms include tan and necrotic interveinal spots with chlorotic margins on leaflets, after effluence in plant, the systemic wilting will occur. So, in summer of 2021 beans fields in different regions of Lorestan province were explored. In some fields in two regions including Beiranshahr and Kakasharaf around Khorramabad, symptoms of bacterial wilt of beans were observed dispersedly on cowpea (Vigna unguiculata L.) and kidney bean (Phaseolus vulgaris L.), suspicious plants were sampled. Infected leaves were cultured on YPGA (yeast peptone glucose agar) and were incubated in 25 ℃ away from the light. The yellow-colored colony were observed after 48 h, and gram stain method revealed gram-positive bacteria. So, for accurate detection of pathogen, specific PCR method was carried out and two CffFOR2 5' - GTTATGACTGAACTTCACTCC-3' and CffREV4 5' -GATGTTCCCGGTGTTCGA-3' primers were used. According to disease symptoms, morphological features, obtained band and negative control, Curtobacterium flaccumfaciens pv. flaccumfaciens was the isolated pathogen, which was reported for the first time from Lorestan.