Identification of Leptosphaeria maculans and Leptosphaeria biglobosa isolates based on pathogenicity and production of sirodesmin pl.

Abstract

The aim of this study was to identify isolates within the pathogenic species of Leptosphaeria maculans and Leptosphaeria biglobosa, based on the pathogenicity and phytotoxin production. The fungus cultures were isolated from rapeseed plants showing the symptoms of stem canker. They were collected from nine locations in rapeseed growing region of northern Serbia. In the study were used 119 local isolates from Serbia and two reference isolates from the Center for Agricultural Research, Rothamsted, Great Britain, (L. m. for Leptosphaeria maculans, and L. b. for Leptosphaeria biglobosa). The pathogenicity of the isolates was examined on the Westar, Glacier and Quinta rapeseed cultivars. Eight isolates caused small necrotic spots on cotyledons in all tested cultivars, while 111 caused large necrotic spots in which the formation of pycnidia was observed. Four local isolates (K-113, C-3, St-5 and S11) and reference isolate L.m. were used for the extraction and isolation of phytotoxins, based on their morphological and pathogenic characteristics. Isolates C-3, St-5, S-11 and L. m. did not produce a yellow brown pigment in the Czapek medium but produced sirodesmin PL while the K-113 isolate produced a yellow brown pigment and did not produce sirodesmin PL.