EARLY DETECTION OF Ganoderma CAUSING BASAL STEM ROT DISEASE IN COCONUT PLANTATIONS

Basal stem rot disease of coconut caused by Ganoderma lucidum (Leys) Karst is prevalent throughout the world, causing significant damage and losses to coconut plantations. The pathogen is soil-borne in nature. For early diagnosis, different techniques viz., enzyme-linked immunosorbent assay, dot immunobinding assay and polymerase chain reaction have been used in modern era of plant pathology. In this study, we have tried ELISA and DIBA using the monospecific antibodies raised against a distinct common protein with a molecular weight of 62 kDa. The protein was observed in all the isolates of Ganoderma. collected throughout Tamil Nadu, India, by the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and variations in the protein patterns were found between Ganoderma isolates. The polyclonal antisera were developed against the purified single protein of Ganoderma. The presence of the 62 kDa protein in the crude mycelial extract was confirmed by western blot analysis. Using the antisera, the pathogen was detected by Indirect ELISA and dot immuno binding assay (DIBA) which resulted in positive reactions for infected samples and negative reactions for apparently healthy palms. These serological techniques gave better results in early diagnosis of field samples, and it could be adopted for large-scale application.