Investigating the Endophyte Microbes and Its Potential as a Biological Control for Ganoderma Boninense that Caused Basal Stem Root(BSR) Disease

Lim, Yee Ching (2018) Investigating the Endophyte Microbes and Its Potential as a Biological Control for Ganoderma Boninense that Caused Basal Stem Root(BSR) Disease. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

G. boninense is a white rot fungus that caused Basal Stem root (BSR) disease and threaten the oil palm plantation in Malaysia. Infected oil palms can be as young as 6-12 months and the detection of BSR is extremely difficult as no visible symptoms appeared in early stage. The aim of this study was to investigate the potential endophytic bacteria that can suppress G.boninense and evaluate the possible mechanism used by endophytes in the suppression of G.boninense. Two endophytic bacteria, SL22 and SL14, and G. boninense were isolated from infected oil palm. Microscopy analysis showed that SL22 and SL14 were identified as gram negative and rod shaped while the G. boninense was observed to have the formation of hyphae with clamp connections. Dual culture assay showed that SL22 had more than 50 percentage inhibition of radial growth (PIRG) while SL14 only had less than 50 PIRG, indicating that SL22 have significantly (p<0.05) higher supressing effect than SL14. The hyphal structure of fungus was observed to have severe distortions under microscope after dual culture assay. Colloidal Chitin Agar (CCA) analysis showed that clear hydrolysis zone was formed by bacteria SL22(YC) and SL14 separately, suggesting that these endophytic bacteria are potential chitinolytic bacteria. Dinitrosalicylic acid (DNS) assay result showed that secretion of glucose increased when G.boninense treated with SL22(YC) and SL14 endophytic bacteria, indicating that SL22(YC) and SL14 can secrete chitinase and degrade the hyphal structure of G. boninense. In conclusion, bacteria SL22(YC) and SL14 have great possibilities to be used as biological control to suppress the growth of G. boninense in oil palm.