[Isolation and screening of a phytate phosphate-solubilizing Paenibacillus sp. and its growth-promoting effect on...

The phosphate-solubilizing medium plate screening and heavy metal resistance rescreening were used to isolate a phosphate-solubilizing bacterium (coded ZLT11) from the rhizosphere of Mikania micrantha. Results from 16S rRNA gene sequence analysis revealed that the strain ZLT11 belonged to Paenibacillus sp. The amount of phosphorus solubilized from calcium phytate and phytic acid by the ZLT11 was 84.10 and 73.84 mg·L^-1, respectively. The maximum phosphate solubilizing activity to calcium phytate (95.66 mg·L^-1) was at 30 ℃ and initial pH 9.0. The strain ZLT11 displayed the tolerance to ≤ 400 mg·L^-1 Pb ²⁺, ≤ 100 mg·L^-1 Cd ²⁺, and ≤ 40 mg·L^-1 Hg ²⁺. With calcium phytate as phosphorus source, the inoculation strain ZLT11 treatment increased the average root length, root number, seedling height and total biomass of rice seedlings by 106.7%, 76.6%, 49.0% and 46.3%, respectively. The strain ZLT11 could improve rice seedlings growth under Cd stress.