Biocontrol Potential of Endophytic Bacteria Originated from Roots of Ravenala Madagascariensis Against Fusarium Oxysporum and Banana-Parasitic Nematodes

Abstract

Ravenala madascascariensis has good resistance to nematode infection. This is thought to be related to endophytic bacteria associated with the plant. This study aimed to isolate endophytic bacteria from the R. madascascariensis roots and test its ability as a biocontrol agent against Fusarium oxysporum and banana-parasitic nematodes. Endophytic bacteria were isolated using NA and TSA media. Potentially safe bacteria for plants and mammals are tested to inhibit the growth of F. oxysporum in vitro. Isolates that can inhibit F. oxysporum were tested for their effectiveness in suppressing banana-parasitic nematode populations in vitro. Furthermore, the selected isolates were tested for their ability to increase the growth of Cavendish banana in the greenhouse. The results showed 113 isolates of endophytic bacteria were successfully isolated; 37 of them were safe for plants and mammals. There were five isolates that could inhibit the growth of F. oxysporum with inhibition percentage of 47.62% up to 66.55%. The five isolates can also suppress bananaparasitic nematode populations in the treatment periods of 2 h, 6 h, and 12 h. The Highest mortality was performed by NAP05 Isolate at 12 H treatment duration, with a mortality value of 63.96%. The Isolates obtained were known to be able to produce several compounds such as protease enzymes (5 isolates) and chitinase enzymes (2 isolates), also capable of dissolving phosphate (3 isolates). The Greenhouse experiment showed that several bacterial isolates were effective in increasing the diameter of banana stems (NAP21 isolate) and fresh roots weight (TAP18, TAP34, And NAP21 isolates). All Isolates were reported to be able to suppress nematode populations in the roots of banana.