Paenibacillus spp. may facilitate anaerobic soil disinfestation under low temperature condition

Abstract We screened bacteria that may promote the suppressive effect on Ralstonia solanacearum in anaerobic soil disinfestation (ASD) using 1% ethanol at low temperatures (< 30℃). Among 22 isolates grown under anaerobic condition, we selected three isolates that their inoculation significantly suppressed the R. solanacearum population after ASD at 25℃. Based on the 16S rRNA sequences, two isolates were inferred as Paenibacillus polymyxa and the other as Paenibacillus sp. Using qPCR primers designed for these strains, we found that all strains increased in the soil after ASD at 25℃. When ASD was performed using 1% ethanol inoculated with or without these three strains in a concrete frame field site for the mean temperature of 26.3℃, the R. solanacearum population was significantly decreased in the inoculation treatment at the depth of 10 cm. These results suggest that these Paenibacillus strains have the potential to promote the ASD effect using 1% ethanol at low temperatures.