Burkholderia cepacia strain IISRCLRB5, A Promising Bioagent for the Management of Rhizome Rot of Turmeric (Curcuma longa L)

The efficacies of 15 rhizobacterial isolates collected from different rhizosphere soils of ginger and turmeric were tested for their ability to inhibit the growth of three Pythium spp. viz., Pythium aphanidermatum, P. myriotylum and P. vexans causing rhizome rot of turmeric, ginger, and cardamom respectively. In vitro studies revealed that the isolate IISRCLRB5 was very inhibitory showing more than 70% inhibition when inoculated simultaneously with Pythium spp. and complete inhibition was obtained on sequential inoculation i. e., by inoculating bacteria first followed by inoculating Pythium spp. after 48 h on dual plate assay. Further in planta evaluation of the isolate against P. aphanidermatum in one month old turmeric plants revealed 56.67% reduction in disease incidence when the rhizobacterium and P. aphanidermatum inoculated simultaneously and 100% rhizome rot suppression when treated with rhizobacterium 48 h before the pathogen inoculation (sequential inoculation). The biocontrol activity of IISRCLRB5 was reconfirmed by another pot culture experiment using four months old turmeric plants and the activity was compared with the fungicide metalaxyl mancozeb-72% WP in the recommended concentration (0.125g/ 100mL). The isolate was subjected to various identification modules viz., phenotypic, biolog identification and molecular sequencing and identified as Burkholderia cepacia. The isolate was further studied for the plant growth promoting and pathogen-inhibiting properties. The isolate is found positive for nitrogen fixation, siderophore production, IAA production, ammonia production, phosphate solubilization, potassium utilization, αamylase production and protease production.