Mycolytic Bacteria as Potential Biocontrol Agent Against Phytopathogenic Fungi of Piper Nigrum

In recent years, phytophthora rot, a slow decline and anthracnose disease are widely spread among black pepper (piper nigrum) cultivation in Sarawak, Malaysia. The infection has caused a tremendous decline in production. Mechanical control, crop management and chemical control are strategies traditionally used to manage the diseases. However, once the soil is infected with pathogens, it is hard and costly to remove it. Biological control is an alternative approach to control the phytopathogens. The strategy of disease management using biological control (BCA’s) is an environmentally friendly approach in which it does not bring any negative effects toward the environment and human health. The five mycolytic enzyme producing bacteria, Acinetobacter calcoaceticus, Chryseobacterium indologenes, Serratia marcescens, Pseudomonas putida and Bacillus cereus were selected to evaluate their antagonistic activities against plant pathogenic fungi, Fusarium solani, Phytophthora capsici and Colletotrichum gloeosporioides by dual culture test, double plate assay and mycelial growth test. In dual culture test, S. marcescens had the highest PIRG value among all the mycolytic bacteria against F. solani, P. capsici and C. gloeosporioides with 33%, 73% and 34% respectively. Meanwhile, in double plate assay, C. indologenes, S. marcescens, A. calcoaceticus, B. cereus and P. putida scored 28%, 21%, 9%, 13% and 23% respectively in PIRG against phytopathogenic fungus P. capsici. C. indologenes and S. marcescens scored 10% and 12% respectively in PIRG against F. solani. Besides that, C. indologenes and S. marcescens scored both 16% in PIRG against C. gloeosporioides. In mycelial growth test, C. indologenes, S. marcescens, A. calcoaceticus, B. cereus and P. putida scored 100%, 100%, 89%, 79% and 73% respectively in PIRG against P. capsici. C. indologenes and S. marcescens scored 5% and 88% respectively in PIRG against F. solani. Apart from that, C. indologenes and S. marcescens scored 11% and 81% respectively in PIRG against C. gloeosporioides. In conclusion, the metabolites of Serratia marcescens showed the greatest potential as biocontrol agents against Fusarium solani, Phytophthora capsici and Colletotrichum gloeosporioides. Further study can be done by combining Serratia marcescens with other types of mycolytic enzyme producing bacteria to identify the effectiveness of inhibiting the fungal disease.