Bacteriostatic stimulus of meropenem on allelochemical-metabolizing Burkholderia sp. LS-044 mitigates ferulic acid autotoxicity in rice (Oryza sativa ssp. japonica cv. Tainung 71)

Aims To screen plant-associated Burkholderia strains for plant probiotic traits including allelochemical metabolism and understand their role on rice allelopathy using a bacteriostatic-dose of antibiotic. Methods Burkholderia sp. LS-044, CC-Al74 and CC-3XP9 were screened for plant probiotic traits. Rice ( Oryza sativa ssp. japonica cv. Tainung 71) root endophytic isolate LS-044 was subjected to multilocus sequence typing, antibiotic assay, and seed germination bioassay under ferulic acid (FA; 0–200 ppm) and bacteriostatic-dose of meropenem (4 ppm). FA metabolism and cell viability were assessed through alamarBlue (AB) assay. Results All tested Burkholderia strains exhibited multiple plant probiotic traits. LS-044, a meropenem-sensitive novel member of Burkholderia cepacia complex displayed rapid metabolism of multiple allelochemicals. Bacteriostatic-dose of meropenem improved germination index (GI) of inoculated seed under FA treatments. Meropenem promoted GI by controlling bacterial FA metabolism and prolonging the cell viability, as evident through AB assay. Uncontrolled bacterial growth under high-dose FA found to be phytotoxic to rice than FA alone. Conclusions Burkholderia sp. LS-044 is a potential allelochemical-metabolizing bacterium, which possibly plays a key role in rice allelopathy. Bacteriostatic-dose of meropenem mitigates autotoxicity by controlling and prolonging allelochemical metabolism of rice-associated LS-044.