اولین گزارش قارچ Pilidium lythri بر روی زغال اخته از ایران

Cornus mas L. (Cornaceae), known as European Corneal or cornelian cherry, is native to southern Europe and south-west Asia. This deciduous shrub with edible and medicinal fruits grows wild in Arasbaran forests located in Azerbaijan province as well as in some regions of Gazvin province in north-western Iran. Very little is known about diseases and disorders affecting this tree in Iran. Septoria corni-mas and Septoria cornicola have already been reported to cause leaf spot and Colletotrichum acutatum as a fruit rot agent on Cornus species in Iran. During a field excursion to the Arasbaran forests in Horand region located in East Azerbaijan province in October 2017, a new fruit rot disease was observed on this host. Fruit samples were collected in a paper bag from heavily infected Cornus mas trees in this region and taken to the laboratory. The causal agent of the diseases was identified as Pilidium lythri based on a combination of morphological and cultural characteristics. The identity of the species as P. lythri was further confirmed using sequence data from ITS-rDNA region. Based on the results of pathogenicity test conducted in laboratory condition, P. lythri was pathogenic on cornelian cherry fruits. Genetic diversity between P. lythri isolates from cornelian cherry (one isolate) and strawberries (10 isolates) was evaluated using RAPD and M13 markers. No polymorphism was detected within and among the isolates, indicating that limited genetic variability may be due to the lack of recombination events. Given recent outbreaks and the presence of the pathogen in most C. mas growing areas in East Azerbaijan province, the life cycle, distribution and the impact of disease on crop yield remain to be studied.