Characterization of Turkish isolates of Pseudocercospora griseola the causal agent of angular leaf spot of common beans

Abstract

Characterization of angular leaf spot (ALS) disease of beans caused by Pseudocercospora griseola (Sacc.) Crous & Braun along with its occurrence was investigated using 118 isolates obtained from beans grown in greenhouses in the western Black Sea region of Turkey. Incidences of ALS disease ranged between 77–100% and 82–100% for summer and autumn sown bean cultivations while the disease severity was in the ranges of 66–82% and 74–86% for the same periods, respectively. All of the 118 isolates of P. griseola yielded 500–560 bp PCR products from ITS1 and ITS4 primers, while 45 isolates yielded 200–250 bp products from actin genes primer and 5 isolates yielded 300–350 bp from calmodulin primer. The form of the Turkish isolates of P. griseola was determined as f. griseola since ITS sequences of 118 isolates of P. griseola showed between 98–100% similarity to the isolates of P. griseola f. griseola deposited in GenBank and our isolates took place on the same branch on the phylogenetic tree formed by the representative isolates in GenBank. The actin sequences did not give a clear differentiation for the forms of P. griseola. The phylogenetic trees generated by ITS1, ITS2 and actin genes formed similar branches. Each had two main clade and similar sub clades.

Keywords

• angular leaf spot
• bean
• disease
• fungus