Bacteria isolated from the ectomycorrhizosphere of Castanea henryi weather insoluble inorganic phosphates and simultaneously form carbonates

Abstract:

[Objective] Ectomycorrhizal fungi can shape the bacterial community in the ectomycorrhizosphere, which represents an important way to mobilize and acquire insoluble mineral elements from the soil. This study aims to investigate the composition and phosphate-solubilizing characteristics of the dominant phosphate-solubilizing bacteria (PSB) in the ectomycorrhizosphere of Castanea henryi. [Methods] The transparent halo method was employed to isolate PSB from the ectomycorrhizosphere of C. henryi. The strains were identified by 16S rRNA gene sequencing. The degradation abilities of the strains for tricalcium phosphate (TCP) and apatite were studied by liquid fermentation. A scanning electron microscope and a X-ray diffractometer were used to observe the appearance and crystal structures of the degradation products. [Results] Five highly efficient strains of PSB were isolated from the ectomycorrhizosphere of C. henryi. Strains LSCh1, LSCh2, and LSCh5 were identified as Burkholderia lata, and strains LSCh3 and LSCh4 were identified as Paraburkholderia sp. The degradation abilities of the strains for TCP followed the trend of LSCh3 (556.94 mg/L)＞LSCh2 (206.91 mg/L)＞LSCh1 (170.83 mg/L)＞LSCh5 (55.16 mg/L)＞ LSCh4 (14.21 mg/L). The degradation abilities of the strains for apatite were in a descending order of LSCh2 (51.33 mg/L)＞LSCh1 (43.51 mg/L)＞LSCh3 (40.99 mg/L)＞LSCh5 (1.11 mg/L)＞ LSCh4 (1.00 mg/L). [Conclusion] Strain LSCh3 showed good performance in degrading both TCP and apatite and induced the formation of carbonates. It is a plant growth-promoting bacterium with potential application values in improving the phosphorus nutrients of plants and the quality of soil.