Streptomyces sp. as Potential Biocontrol for Fungal Phytopathogen, Ganoderma boninense
Streptomyces sp. as Potential Biocontrol for Fungal Phytopathogen, Ganoderma boninense
Muhammad Asyraff Abd Samad, Abdul Munir Abdul Murad, and Izwan Bharudin*
Department of Biological Sciences and Biotechnology, Faculty of Science and Technology,
Universiti Kebangsaan Malaysia, UKM Bangi, 43650 Malaysia
*Email: ibb@ukm.edu.my
Malaysia and Indonesia contribute more than 80% to the global palm oil market. However, the sustainability of the oil palm plantations is threatened by a disease known as Basal Stem Rot (BSR) caused by fungal pathogen, Ganoderma boninense. Nearly 60% of plantation areas were reported with the disease, causing huge economic losses to both countries (up to USD500 million/year). To date, there are no effective methods to halt the continuing spread of the fungus. Thus, we aim to identify the potential microorganisms and determine their specific compounds (volatiles and non-volatiles) with antifungal properties that can inhibit the growth of the fungal pathogen. The dual-culture assay method was used to determine the ability of Streptomyces sp. to secrete the non-volatile compounds whereas the dual-chamber assay was used to identify the non-volatile compounds. Gas chromatography-mass spectrometry (GC-MS) analysis was used to identify the volatile organic compounds (VOCs) whereas liquid chromatography-mass spectrometry (LC-MS) analysis was used to identify the non-volatile compounds produced by the microorganism. Several known antifungal VOCs produced such as dimethyl disulfide (DMDS) and 2-heptanone, 6-methyl were identified from the GC-MS analysis. Moreover, LC-MS analysis also identified a few known antifungal compounds such as aureothin and 3-amino-2-nitrophenol. Furthermore, the introduction of Streptomyces sp. to the co-culture (oil palm-G. boninense) has reduced the BSR symptoms drastically in the artificial infection assay. Thus, it shows that Streptomyces sp. is a promising candidate to be used as a biocontrol agent against G. boninense and will be applicable for BSR disease management and prevention.
