微波诱变选育高产生长素及耐药性根瘤菌株研究

SCREENING OF HIGH IAA-PRODUCING RHIZOBIUM STRAIN WITH ANTIBIOTIC-RESISTANCE USING MICROWAVE MUTAGENESIS

为获得高效分泌IAA(吲哚乙酸Indoleacetic acid),同时具有卡那霉素(Kanamycin)和氨苄青霉素(Ampicillin)双抗药性的根瘤菌突变株,以红豆草根瘤菌(Rhizobium Onobrychis vicilfolia)RS-1为原始菌株进行微波诱变处理,对微波诱变参数进行了优化,并以含抗生素平板筛选出卡那霉素和氨苄青霉素双抗药突变菌株,以多次传代的方式考察了突变菌株的遗传稳定性和生长素产量。结果显示,最优微波诱变参数为800W、6s,该参数下诱变获得5株高产生长素及双耐药突变株RSW-14、RSW-55、RSW-62、RSW-96和RSW-107。传代试验表明RSW-96是稳定的高产生长素、耐药突变株,表现在RSW-96传代6次后对80 mg/L卡那霉素和300 mg/L青霉素具有抗性,培养4 d和24 d的IAA产量比原始菌株提高了66.93%和50.15%,单株生物量增加效果高于原始菌株25.58%,具有良好的促生效应。

In order to obtain high IAA-producing rhizobium strain with antibiotic-resistance of kanamycin and ampicillin, the IAA-producing rhizobium strain RS-1 was treated by microwave. The mutagenesis parameters were optimized, and the genetic stability, IAA-producing potential and antibiotic resistance of the mutant were investigated by continuous subcultures. Results show that： 5 high IAA-producing strains with two antibiotic-resistance named RSW-14, RSW-55, RSW-62, RSW-96 and RSW-107 were obtained through the microwave irradiating （800W, 6s）. Subculture test indicated that RSW-96 had relatively stable hereditary characteristics of IAA-producing capability and antibiotic resistance. It displayed mainly： Upon continuous subculture more than 6 generations, RSW-96 keep the ability of resistance to 300mg/L ampicillin and 80mg/L kanamycin, and the IAA-producing potential reaching 8.38mg/L （4d） and 50.75mg/L （24d）, which were 40.09% and 50.15% higher than the parent strain, respectively. The biomass increasing rate of RSW-96 were 25.58%, higher than its parent strain significantly （ P 〈 0.05）.