Molecular Identification of Fungal Species Causing Brown Circular Leaf Spot Disease in Seedlings of Siamese Rosewood (Dalbergia cochinchinensis Pierre ex Laness)

Abstract

Morphological and pathological features of fungi isolated from leaves of Dalbergia cochinchinensis Pierre ex Laness seedlings (Siamese rosewood) with brown circular leaf spot disease have previously been reported. According to morphology, there are different fungi that cause this disease but information is only available on the fungi genera e.g. Curvularia sp. , Alternaria sp., and Colletotrichum sp. including an unknown rust fungus. In order to identify the species of these fungi, molecular identification using information derived from the amplification of internal transcribed spacer sequences ( ITS) via ITS1, ITS4 and ITS5 primers and phylogenetic analysis was performed. According to the results obtained from the analysis using Neighbor– joining method, the isolated fungal species from the diseased leaves were revealed as Alternaria alternata, Colletotrichum siamense, Curvularia aeria and Maravalia pterocarpi, with supportive bootstrap scores. This research reports the occurrence of the fungal species on this plant to provide additional data for controlling the causal agents of the disease in a more specific and targeted manner.