Identification of Soil Bacteria with Antifungus Activity towards Palm Oil Pathogen, Ganoderma boninense

Abstract

Basal Stem Rot disease (BSR) caused by the phytopathogenic fungus Ganoderma boninense is a huge threat to the oil palm plantations in Malaysia. BSR can reduce the yield of oil palm fruit bunch and cause fatality on infected oil palm trees thus creating huge economic losses to the producing country. The use of chemical fungicides has been applied in addressing BSR, however these methods were unable to overcome the fungal attack. A few studies have been carried out to identify the potential of biological control agents such as antagonistic microorganisms in controlling BSR disease. This study aimed to identify locally isolated microorganisms having antagonistic effects against G. boninense. A total of 49 pure bacterial cultures were isolated from Bangi, Selangor, Malaysia. Three isolates namely two from genus Burkholderia and one from Streptomyces showed strong antagonistic activity against G. boninense dikaryotic micellia with more than 70% of Percentage Inhibition of Radial Growth (PIRG) in two different antifungal assays. DNA sequence analysis of all isolates showed that the bacteria species shared high similarities in their 16S rRNA sequences with Burkholderia stagnalis, B. cepacia and Streptomyces gelaticus. The bacteria found in this study have high potentials to be used as biological control agents in preventing the spread of G. boninense, particularly in the oil palm plantations in Malaysia.