گزارش پوسیدگی نرم سیر ناشی از Pectobacterium carotovorum در استان لرستان

Garlic is considered as one of the most important crops in Iran and specially in Lorestan Province. Soft rot is one of the important bacterial diseases of garlic, which reduces yield, and has threatened garlic production in Lorestan province in recent years. In this study, samples showing symptom of soft rot were collected from garlic fields and transferred to the laboratory. After surface sterilization with 5% sodium hypochlorite solution, tissues with symptoms were squashed in the mortar containing sterilized distilled water under sterile condition. Subsequently, a few drops of extract were cultured on nutrient agar (NA), Eosin methylene blue (EMB) and King's B and incubated at 28 °C for three or four days. After the emergence of colonies, target colonies were selected based on colony morphology and shape. To obtain purified colonies, colonies were sub-cultured on nutrient agar. To carry out pathogenicity test, a bacterial suspension (5 µl) containing 108 colony-forming units per ml (CFU ml-1) was inoculated into the wounds. To confirm Koch’s postulates, bacteria re-isolated from diseased bulbs were streaked on NA and reidentified. Physiological and biochemical features were characterized based on standard bacteriological criteria to the species level. A pair of specific primers (PCCSSF / PCCSSR) was used to detect these bacterial strains. Based on the results of biochemical tests and molecular identification using PCCSSF / PCCSSR and 16s rRNA amplifying primers (FD1 / rD1), the isolates were identified as Pectobacterium carotovorum. To the best of the knowledge, this is the first report of the occurrence of this disease in Lorestan province.