锥栗外生菌根际细菌对难溶性无机磷风化作用及其耦联碳酸盐形成研究

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

摘要:

【目的】外生菌根真菌在菌根际塑造特异的细菌群落是从土壤中活化和获取不溶性矿质元素的一个重要途径。本研究旨在探究锥栗外生菌根际解磷细菌的组成及其解磷特性。【方法】通过溶磷圈法从锥栗菌根际分离解磷细菌，并运用16S rRNA基因测序进行菌株鉴定，采用液体发酵方式比较分析解磷菌对磷酸三钙和磷灰石的降解能力，利用扫描电镜和X射线衍射仪对风化降解产物微观形貌和晶体结构进行分析。【结果】分离获得5株高效解磷菌，经16S rRNA基因测序和比对分析，LSCh1、LSCh2和LSCh5菌株被鉴定为拉塔伯克霍尔德菌(Burkholderia lata)，LSCh3和LSCh4被鉴定为副伯克霍尔德菌属(Paraburkholderia sp.)。解磷实验结果表明不同菌株对磷酸三钙的降解能力依次为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)，对磷灰石的降解能力依次为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)。【结论】LSCh3菌株不仅对磷酸三钙和磷灰石都具有较好的降解能力，而且能够诱导碳酸盐的形成。该菌株是一株具有重要潜在应用价值的植物促生菌，可用于促进植物磷营养和改善土壤质量。

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.