具有ACC脱氨酶活性的红枣根际促生菌株的分离筛选及其促生效果研究

采用定向富集法从红枣根际土壤分离筛选具有ACC脱氨酶活性的细菌，同时检测其产生长素（IAA）、固氮和解磷等促生特性。结合形态特征和16S rDNA序列分析对菌株进行鉴定，并采用盆栽试验验证3株高效产ACC脱氨酶的根际促生菌株Pseudomonas fluorescens、Pseudomonas putida和Serratia plymuthica对红枣植株生长的影响。结果表明:1）从红枣根际共分离出10株产ACC脱氨酶的菌株，其ACC脱氨酶活性在14.23~433.05 μmol/(mg·h)。这些菌株都具有产IAA、固氮和解无机磷能力。2）经鉴定，10株菌株分别属于假单胞菌属（Pseudomonas）、芽孢杆菌属（Bacillus）和沙雷氏菌属（Serratia）。3）接种Pseudomonas putida菌剂和Serratia plymuthica菌剂均可显著促进红枣植株生长发育，提高植株株高、生物量、叶片氮及磷含量。2种菌株的接种效应明显优于Pseudomonas fluorescens菌剂，且复合菌株应用促生效果优于单一菌株。

Isolation,Screening and Promoting Effects of Plant Growth-promoting Rhizobacteria (PGPR) Containing ACC Deaminase from Jujube

In this study,1-aminocyclopropane-1-carboxylate (ACC) deaminase producing plant growth bacteria were isolated from the rhizosphere of jujube by using the method of enrichment culture.The bacteria isolates were identified by 16S rDNA sequences analysis.Their growth promoting traits such as indole acetic acid (IAA) production,nitrogen fixation,and phosphate solubilization were evaluated.Effects of Pseudomonas fluorescens,P.putida,and Serratia plymuthica on the jujube growth were verified by pot experiment.The results were as follows:1) Ten bacterium strains were isolated and identified under the genera Pseudomonas,Bacillus,and Serratia.The ACC deaminase activities of these strains were among 14.23-433.05 μmol/(mg·h).All of isolates had abilities of IAA secretion,nitrogen fixation and phosphate solubilization.2) Ten strains with ACC deaminase,isolated from rhizosphere soils of Ziziyhus jujuba,were identified as Pseudomonas,Bacillus and Serratia.3) Inoculation of P.putida,and S.plymuthica significantly improved the plant growth.The plant height,biomass,nitrogen,and phosphorus content in the leaves enhanced accordingly.The inoculation effects of the two bacterium strains were superior to those of P.fluorescens,and the inoculation effects of the co-inoculation were superior to those of single bacteriium strains P.fluorescens,P.putida or S.plymuthica.