Polyphasic characterization and pathogenicity of Colletotrichum theobromicola on pomegranate (Punica granatum) in Iran

Pomegranate (Punica granatum) is nourishing fruit with several useful medicinal and health properties. Fruit rot diseases are among the main constrains for pomegranate production worldwide, which may occur in orchards or as post-harvest diseases during storage. Anthracnose disease caused by Colletotrichum species is one of the important diseases of pomegranates in many pomegranate producing countries; however, there is a paucity of knowledge on the occurrence and the identity of Colletotrichum spp. causing anthracnose disease on pomegranate in Iran.  In recent years, there has been a significant prevalence of pomegranate fruit rot symptoms, resembling anthracnose disease in the pomegranate orchards of Golestan province. Therefore, the current research was aimed to characterize the causal agent of the disease and also evaluate their pathogenicity on pomegranate fruit. For this purpose, sampling was done from the pomegranate orchards of Golestan province during ۲۰۲۱ growing season. Isolation and purification of fungal isolates was done using common methods in plant pathology on acidified potato dextrose agar (PDA) culture medium. The isolates were identified by combining morphological traits with sequence data of the ITS-rDNA genomic region and beta-tubulin (BUT) gene. By combining morphological data with molecular data, the isolates were identified as Colletotrichum theobromicola (C. gloeosporioides species complex). The results of pathogenicity tests on pomegranate fruit in laboratory conditions showed that the mentioned isolates caused symptoms five days after inoculation. Even though several Colletotrichum species in C. gloeosporioides and C. acutatum species complexes are known to cause fruit anthracnose and leaf blight symptoms on pomegranate worldwide, in the present study C. theobromicola was isolated as the sole causal agent of the disease for the first time in Iran. Geographical distribution, economic impact and ecology of Colletotrichum spp. in pomegranate producing areas in Iran remain to be studied.

کلیدواژه ها:

fruit rot ، Multigene phylogeny ، Pathogenicity assay ، Colletotrichum gloeosporioides species complex