دو گونه جدید از Neoscytalidium به عنوان عوامل شانکر ناتراسیایی در ایران

Nattrassia canker is one of the major pathogen of different plant species in southern and central provinces of Iran. During 2015-2016, disease samples showing dieback, canker with cortex flacking filled with black powder were collected from Fars, Kerman, Khozestan, Hormozgan, Isfahan and Sistan and Balochestan provinces. Symptomatic tissues were washed and surface sterilized in 0.5% sodium hypochlorite and small pieces were incubated on acidified PDA at 25oc. The growing colonies were purified using hyphal tip and single arthrospore. Using morphological features the isolates were identified as Neoscytalidium and the species were verified using molecular approach. DNA was extracted using CTAB method and PCR was conducted using primers ITS1-ITA4 (Internal Transcribed Spacer), EF1-EF2 (Elongation Factor 1 alpha) and b-tubulin A and B (Beta-tubulin).. The maximum. Optimum and minimum temperature for growth were respectively 40,35 and 15oc.The pathogenicity of the isolates was performed on detached stems of maple, mulberry, elm ,ailanto, apple, plane tree, olive and pistachio. Based on molecular criteria three species of Neoscytalidium Namely N. dimidiatum, N. hyalinum and N. novaehollandia were identified which the two latter species are new for Iran flora. Colony of N. hyalinum appeared as white powder which gradually changed to light olive but N. novaehollandia first appeared as olive and turned to dark color. This is the first report of appeared as olive and turned to dark color. This is the first report of N. hyalinum on date palm and N. novaehollandia from citrus, olive,elm ,pomegranate and mulberry from Iran.
Keywords: dieback, morphological, molecular, CTAB