Black leaf spot: Important disease of parsley in Serbia

Abstract

In the period 2005-2014, total of 19 isolates of Alternaria petroselini originating from parsley leaves, taproot and seed, as well as infested soil were collected and analyzed on the bases of morphological, pathogenic and molecular features. All isolates formed dark gray colonies on PDA and subsurfacely produced microsclerotia, as well as pigmented, broadly ellipsoidal, singly feodyctiosporic conidia. Pathogenicity and host range studies using spore suspension spray inoculation, revealed that isolates were pathogenic for parsley, parsnip, celery and coriander, weakly pathogenic for carrot, fennel and anise, and not pathogenic for onion, cabbage, pepper, tomato, and cucumber. Molecular detection utilizing A. radicina specific primers failed to demonstrate difference between two closely related but diffe­rent species, A. radicina and A. petroselini. For further confirmation of idendty of Serbian A. petroselini isolates, sequencing of selected genomic fragments including ITS rDNA, Alt a1 and EF1a protein coding genes was performed. BLAST search revealed that the most reliable molecular delineation between A. petroselini and closely related species could be achieved on the bases of sequence analysis of Alt a1 and EF1a genes (25-27, and 10-12 nucleotide differences from A. radicina isolates, respectively), while sequence of ITS rDNA were helpful, but not completely informative for identification of A. petroselini isolates.