桃树根际铁载体产生菌MX-26的分离鉴定及诱变选育

Isolation,characterization and mutation breeding of siderophore-producing bacterium MX-26 of peach rhizosphere

从桃树根际土壤中分离到81株细菌,通过铬天青(chrome azural S,CAS)检测法筛选出一株产铁载体能力较强的细菌菌株MX-26,经形态、生理生化特征鉴定及16S rDNA序列分析,确定MX-26为克雷伯氏菌属产酸克雷伯氏菌Klebsiella oxytoca。以MX-26为出发菌株,对其进行紫外诱变、紫外和氯化锂复合诱变及硫酸二乙酯(DES)诱变,得到菌株的最佳诱变组合:紫外线照射时间为180 s,氯化锂终浓度为1.2%,硫酸二乙酯诱变时间为40 min。诱变获得菌株MX26-18,其产铁载体能力较出发菌株提高了32.9%,且遗传性能较稳定。

Using the chrome azural S（CAS） reagents assay,a siderophore-producing bacterium MX-26 was screened out from 81 bacteria,which were isolated from the peach rhizosphere soil.According to morphological,biochemical characteristics and 16S rDNA sequence analysis,strain MX-26 belong to Klebsiella oxytoca.As an original strain,MX-26 was mutated by UV-ray,complex mutagenesis of UV-ray and lithium chloride（LiCl）,diethyl sulphate（DES）,the optimum mutagenesis conditions were determined： mutated by UV-ray was tested to be 180 seconds,the concentration of lithium chloride should be 1.2% and mutated by the diethyl sulphate was tested to be 40 minutes.The mutants of strain MX26-18 was obtained.Compared with MX-26,the siderophore production from MX26-18 was increased by 32.9%.And the subculture experiments indicated that the hereditary characteristic of MX26-18 was stable.