Isolation and characteristics of two Bacillus spp. from the rhizosphere of Lactuca sativa

Abstract:

[Objective] To isolating the Bacillus strains from the rhizosphere of Lactuca sativa, which have a variety of biological characteristics, the growth-promoting ability and effects of biocontrol. [Methods] In the study, high-temperature method was used to separate Bacillus spp.. The strains were identified according to morphological characteristics, physiological and biochemical responses, 16S rRNA and gyrB gene analysis. The phosphate solubilization, IAA syntheses, siderophore syntheses, the inhibition against the plant pathogenic fungis of two strains were studied. Planted the lettuce seeds soaked with the suspension liquid of two strains, and evaluated the effects of the growth-promoting after 30 days. Using the strain WXD 3-2 treated with wheat, evaluated the effects of inoculum concentrations of WXD 3-2. [Results] The strain WXD 3-1 was identified as Bacillus megaterium and WXD 3-2 was confirmed as Bacillus subtilis. Two strains had phosphate solubilization, IAA syntheses, siderophore syntheses, and the growth-promoting ability. The strain WXD 3-2 could inhibit varieties of plant pathogenic fungis. The height of the lettuce, the width of leaves, the fresh weights, and the dry weights were increased 21.51% and 8.88%, 31.93% and 14.51%, 41.30% and 13.58%, 42.76% and 26.35% compared with control. The results showed that the strain WXD 3-2 could reduce wheat root rot disease and wheat root lesion. [Conclusion] Two strains had phosphate solubilization, IAA syntheses, siderophore syntheses, and growth promotion ability. The strain WXD 3-2 had effects of biocontrol.