苹果树根际高效解钾菌的筛选及鉴定

Isolation and Identification of Potassium-Solubilizing Bacteria from Rhizosphere Soil of Apple Tree

为探明苹果树根际解钾菌的种群特征和解钾性能,从苹果树根际土壤中分离获得解钾能力较强的高效解钾菌。本研究以钾长石为唯一钾源,分离获得118株具有解钾活性的菌株,重复片段PCR基因指纹分析(Repetitive-element PCR,rep-PCR)聚为29个类群。利用火焰分光光度法测定菌株解钾能力,获得5株高效解钾菌,平均解钾活性达到41.47mg·L-1,其中K105的解钾能力最强,有效态钾增长23.09%。采用H2O2消煮后测得的K+浓度升高,有效态钾增长最高达31.22%。采用形态特征观察、生理生化特性检测和基于16S r RNA基因序列的系统发育分析对高效解钾菌株进行鉴定。结果表明:K1为不动杆菌属(Acinetobacter sp.)、K98、K105和K115为假单胞菌属(Pseudomonas sp.)、K168为芽孢杆菌属(Bacillus sp.)。研究结果可为开辟新型高效解钾菌,为连作土壤的改良和苹果专用微生物菌肥的开发提供依据。

In order to detect the population properties and potassium-dissolving characteristics of potassium-dissolving bacteria existing in apple rhizosphere soil, the highly efficient potassium-dissolving bacterial isolates were gained from the rhizosphere soil of apple trees. 118 strains with the ability of potassium-dissolving were isolated with potassium feldspar as the sole potassium source, then the strains were clustered into 29 populations by analysis of repetitive-element PCR （rep-PCR） genomic DNA fingerprinting. Flame spectrophotometer was used to determine the potassium-dissolving capacity, and 5 highly efficient potassium-dissolving bacteria was obtained, whose average soluble potassium content of culture medium reached to 41.47mg· L-1. K105 performed the highest potassium- dissolving ability, and the available potassium increased by 23.09%. The available potassium increased after being digested by H2O2 solution, the maximum was up to 31.22%. After identifying the isolated 5 strains of efficient potassium-dissolving bacteria by bacterial morphology, physiology and biochemical characteristics, and phylogenetic analysis based on 16S rRNA gene sequences, 5 strains were classified into 4 bacterial genera. K1 belongs to Acinetobacter sp., K98, K105 and K115 belong to Pseudomonas sp., and K168 belongs to Bacillus sp.. It provided basis for exploration of new efficient potassium-solubilizing bacteria, contributing to improve apple replanted soil and develop microbial fertilizer special for apple trees.