山核桃根际解磷及水解复杂有机物细菌的分离

Isolation of bacteria activating phosphorus and hydrolyzing complex organic matter from the rhizosphere soil of Carya cathayensis Sarg

摘要:

【目的】挖掘兼具多种促生功能的山核桃根际解磷细菌(phosphorus-mobilizing bacteria,PMBs)菌株资源，研发多功能生物有机肥，促进山核桃产业绿色、可持续发展。【方法】采用稀释涂布平板法分离获取山核桃根际PMBs，测定其生物学功能并基于16S rRNA基因同源性鉴定其分类学地位。【结果】从山核桃根际土共分离获得34株PMBs，其主要来自厚壁菌门(Bacillota)、变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)、薄壁菌门(Gracilicutes)下的10属细菌，以芽孢杆菌属(Bacillus)(12株)、伯克霍尔德氏菌属(Burkholderia)(9株)、假单胞菌属(Pseudomonas)(5株)3个属菌较多，共计占比76.47%。在含不同难溶性有机/无机磷源的培养基中接种PMBs后，产生的可溶性磷含量范围分别为：7.01−49.97 mg/L (磷酸铝)、3.61−27.11 mg/L (磷酸铁)、4.56−342.82 mg/L (磷酸三钙)、27.71−544.53 mg/L (植酸钠)和3.28−27.17 mg/L (卵磷脂)。其中23株PMBs能同时溶解难溶性无机磷和有机磷。分别有20、7、23、12、10、14、13株PMBs能产吲哚乙酸(indole-3-acetic acid,IAA)、铁载体和胞外蛋白酶、β-1,3-葡聚糖酶、纤维素酶、磷酸酶及脂肪酶，其中菌株S3-6L和S3-22L具有5种生物学功能。【结论】本研究筛选到的PMBs同时具有较高溶解磷的能力和多种生物学功能，丰富了PMB菌种资源，为研发高效、绿色山核桃复合微生物菌肥奠定了基础。

Abstract:

[Objective]Multipurpose bioorganic fertilizers contribute to the sustainable development of the Carya cathayensis Sarg.industry.This work aims to explore the resources of phosphorus (P)-mobilizing bacteria (PMBs) with plant growth-promoting effects from the rhizosphere soil of C.cathayensisSarg.[Methods]PMBs were isolated with the dilution-plate coating method and identified based on 16S rRNA gene homology.Moreover,plate and liquid culture tests were conducted to determine their biological functions.[Results]A total of 34 strains of PMBs were isolated from the rhizosphere soil of C.cathayensisSarg.These PMBs belonged to 10 genera of four phyla:Bacillota,Proteobacteria,Actinobacteriota,and Gracilicutes.Among them,Bacillus(12 strains),Burkholderia(9 strains),and Pseudomonas(5 strains) were the dominant genera,with the strains accounting for 76.47% of the total isolated PMBs.After inoculation of PMBs,the content of soluble P produced by PMBs was 7.01–49.97,3.61–27.11,4.56–342.82,27.71–544.53,and 3.28–27.17 mg/L in the culture media with AlPO₄,FePO₄,Ca₃(PO₄)₂,sodium phytate,and lecithin as the sole P source,respectively.Twenty-three strains were capable of simultaneously mobilize insoluble inorganic and organic P components.Additionally,20,7,23,12,10,14,and 13 strains of PMBs could produce indole-3-acetic acid (IAA),siderophores,extracellular protease,β-1,3-glucanase,cellulase,phosphatase,and lipase,respectively,among which strains S3-6L and S3-22L exhibited five biological functions.[Conclusion] The PMBs identified in this study possess high P mobilization capability and multiple biological functions,enriching the resources of PMB strains and laying a foundation for the development of efficient,green,and composite microbial fertilizers for C.cathayensisSarg.