Antagonistic effects of actinomycetes towards plant pathogen Phellinus noxius

Abstract

Several strains of actinomycetes have been found to protect plant from plant pathogens because the capacity to produce a wide variety of antibiotics, extracellular enzymes and also show their antagonistic effects towards plant pathogen. Actinomycetes play an important role in degradation of chitin which is a component of cell wall of fungi. Application of selected Actinomycetes as biocontrol can decrease the environmental pollution and an alternative to fungicides. Brown root disease caused by Phellinus noxius was observed in teak plantations of Sabak Bernam in Selangor, Kuala Kangsar in Perak, Sik in Kedah and Lendu in Malacca. It will affect the plantations industry if no measures are taken to control or manage it. This pathogen grew faster on the Potato Dextrose Agar and also on selective media such as Malt Yeast Extract Agar. Analysis of the 16S rDNA begins by extracting the Actinomycetes DNA and amplifying the gene coding for 16S rDNA using the polymerase chain reaction. The purified DNA fragments are directly sequenced and identification of the actinomycetes was done using phylogenetic analysis procedures. However, analysis of 16S rDNA generally allows us to identify the organisms up to the genus level only. Three selected actinomycetes isolated from the soil were found to control this plant pathogen. These actinomycetes controlled the plant pathogen by hyperparasiting it and colonizing its hyphae. The chitinase production of actinomycetes was determined by inoculating culture strains on chitin-yeast-extract agar and its chitinolytic activity was determined by formation of clear zones around the actinomycetes colonies.