Philippine Journal of Science
152 (5): 1539-1548, October 2023
ISSN 0031 – 7683
Date Received: 16 Feb 2023
Potential of Indigenous Rhizobacteria
as Biocontrol Agents of Xanthomonas sp.
Siti Marfungah1, Fifi Puspita1, Budi Tjahjono1,2,
Bayo A. Siregar2, and Abdul Gafur2*
1Post-graduate Program, University of Riau,
Jalan Bina Widya KM 12.5, Pekanbaru, Riau 28293 Indonesia
2Sinarmas Forestry Corporate Research and Development,
Jalan Raya Minas–Perawang KM 26, Perawang, Riau 28772 Indonesia
*Corresponding author: gafur@uwalumi.com
[Download]
Marfungah S et al. 2023. Potential of Indigenous Rhizobacteria as
Biocontrol Agents of Xanthomonas sp. Philipp J Sci 152(5): 1539–1548.
https://doi.org/10.56899/152.05.02
ABSTRACT
Bacterial leaf blight (BLB) disease caused by Xanthomonas sp. is one of the main diseases of eucalypt plants. The utilization of rhizobacteria to manage diseases in other agricultural ecosystems has been reported. This study aims to select and characterize rhizobacteria from the rhizospheric zones of Eucalyptus pellita with antagonistic nature against Xanthomonas sp. and to identify isolates that have the best potential as biocontrol agents in the Eucalyptus Xanthomonas pathosystem. The research was conducted in-vitro. The antagonism test was arranged in a completely randomized design with three replications. Characteristics of antagonistic rhizobacteria were examined based on their ability as plant growth-promoting bacteria (PGPR). Identification of potential rhizobacteria was performed based on 16S rRNA sequences. There were 14 isolates showing antagonistic activities against Xanthomonas sp. The results showed that the rhizobacteria had significant antagonistic impacts against the pathogen. Characterization of the 14 isolates indicated that all isolates produced siderophores and indole acetic acid (IAA). As many as 13 isolates produced protease, eight isolates were able to dissolve phosphate, and three isolates synthesized hydrogen cyanide (HCN). The isolate with the highest inhibitory effect was isolate RE081, whose activity was classified as very strong. The RE81 isolate also showed the best properties in the HCN test (+++), IAA production (19,29 mg L–1), and the ability to dissolve phosphates. Molecular analysis of the 16S rRNA gene disclosed that RE81 is Pseudomonas aeruginosa (100%).