Analysis of Kalmusia variispora associated with grapevine decline in Iran

Abstract

Between March and September 2012, grapevines in vineyards of Meshginshahr county located in Ardabil province as well as Azarshahr, Ajab Shir, and Malekan counties located in East Azerbaijan province, north-western Iran represented general decline symptoms and in some cases black vascular discoloration. Annular or irregular discoloration, dark vascular streaking, and V-shaped unilateral canker or brown necrosis were observed in the pit and vascular tissues of the infected stems. These symptoms were accompanied with necrotic and wilted leaves. Nine fungal isolates having analogous morphological traits were recovered from symptomatic tissues on potato dextrose agar culture medium. Morphological and molecular characterizations confirmed the identity of all nine isolates as Kalmusia variispora (formerly known as Dendrothyrium variisporum). Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses were conducted for genetic diversity assessment of 13 K. variispora isolates from grapevine, one isolate from Rosa hybrida and one isolate from Pinus eldarica and the results indicated the existence of polymorphism among the isolates (77.27% and 81.25% for RAPD and ISSR, respectively). The clustering of RAPD and ISSR analyses revealed that there was no correlation between the isolates and their geographical as well as host origins. A pathogenicity assay confirmed K. variispora to be pathogenic on grapevine plants (cv. Keshmeshi) causing similar symptoms as those observed in naturally infected grapevines. Kalmusia variispora is associated with grapevine decline symptoms and grapevine trunk disease in Iran.