Taxonomic study on Valsa sordida species complex, the causal agent of canker disease of trees*

In order to taxonomic investigation on Valsa sordida, the causal agent of canker disease on trees, 125 infected plant specimens were collected from Golestan Province. Based on morphological features, among obtained 49 fungal isolates, 35 isolates were identified as V. sordida. Moreover, asexual morphological characteristics of 12 isolates were nearly similar to C. chrysosperma and named as Cytospora sp.1. Also, morphological characteristics of an isolate (from Populus deltoides) was almost similar to V. sordida and named as Valsa sp.1. Finally, morphological characteristics of an isolate (from Ficus elastica) was different from C. chrysosperma and was near to Cytospora ribis and considered as Cytospora sp.2. To investigate the phylogeny of selected isolates, nucleotide sequence of ITS1-5.8S-ITS2 regions from nuclear ribosomal DNA (rDNA) were determined in 14 isolates (five isolates of C. chrysosperma, seven isolates of Cytospora sp.1, one isolate of Valsa sp.1 and one isolate of Cytospora sp.2), and were used along with 32 related sequences from GenBank (NCBI). The results of molecular grouping confirmed the morphological diversity in the isolates.