EXPLORATION OF ACTINOBACTERIA INDIGENUS AS BIOLOGICAL CONTROL AGENT OF BACTERIAL LEAF BLIGHT (XANTHOMONAS AXONOPODIS PV. ALLII) AND INCREASING PRODUCTION OF SHALLOT.

Bacterial leaf blight, caused by Xanthomonas axonopodis pv. allii, poses a substantial risk to shallot crops. Actinobacteria are promising candidates for biological control because of their ability to generate bioactive compounds. This research aimed to identify the most effective Actinobacteria isolates for managing bacterial leaf blight and boosting the growth and yield of shallot plants. The study was conducted in three phases: 1.) Isolation and characterization of Actinobacteria and X. axonopodis pv. allii, 2.) Selection of Actinobacteria to control X. axonopodis pv. allii and boost shallot plant growth with 21 treatments and three replications, and 3.) Molecular identification and testing of selected Actinobacteria for controlling X. axonopodis pv. allii. This research was carried out in the microbiology laboratory and experimental farm of the Faculty of Agriculture at Andalas University in West Sumatra, Indonesia. The study identified several indigenous Actinobacteria isolates (AT2aP7Y, AS3aA7Y, AA2aP7Y, AS1aP6Y, and AS1aP7Y) with high phosphate solubilizing indices, strong antagonistic activity, and significant abilities in nitrogen fixation and phytohormone (IAA) production. These isolates were identified as Streptomyces spp. and Micromonospora shersina R-Ac134 through 16sRNA sequencing. They demonstrated potential for effectively controlling bacterial leaf blight and enhancing the growth and yield of shallot plants. In conclusion, the indigenous Actinobacteria isolates from the regions of Solok, Tanah Datar, and Agam in West Sumatra show promise as biological control agents against bacterial leaf blight in shallot plants, while also promoting plant growth and productivity. [ABSTRACT FROM AUTHOR]