Abstract

Basal stem rot (BSR) disease caused by the fungus, Ganoderma boninense has become a serious threat to the oil palm industry, especially in Southeast Asia (SEA). A highly selective and sensitive diagnostic tool for BSR is extremely required for early detection, and thus, development of immunological test using enzyme-linked immunosorbent assay-polyclonal antibody (ELISA-PAb) was evaluated. Results indicate that ELISA-PAb shows recognition of Ganoderma species associated with BSR except for G. tornatum. Cross-reactivity test with fungi commonly found in oil palm plantation revealed observation of some cross-reactions with some saprophytic fungi. ELISA-PAb shows better detection as compared to cultural-based method, Ganoderma selective medium (GSM) with an improvement of 18% at nursery trial. The present study also demonstrates sensitive detection on ELISA-PAb with an increment of 30% as compared to GSM test at field trial using oil palm roots and stems. Polyclonal antibodies raised against G. boninense with positive signals was achieved, however, not specific enough for detection of BSR disease caused by Ganoderma.

Key words: Ganoderma boninense, basal stem rot, polyclonal antibodies, enzyme-linked immunosorbent assay (ELISA).

Abbreviation

Abbreviations: BSR, Basal stem rot; ELISA, enzyme-linked immunosorbent assay; OD, optical density; MAb, monoclonal antibody; PAb, polyclonal antibody; EDTA, ethylene diamine tetraacetic acid; PBS, Phosphate buffered saline; PBST, Phosphate buffered saline with tween 20; HRP, horseradish peroxidase; IgG, immunoglobulin; ABTS, 2,2’-azino-di-ethyl-benzothiazoline-6 sulfonic acid; SDS-PAGE, sodium dodecyl sulphate-polyacrylamide gel electrophoresis; GSM, Ganoderma selective medium.