微波诱变选育高产生长素及耐药性根瘤菌株研究

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，最优微波筛选参数为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80mg/L卡那霉素和300mg/L青霉素具有抗性，培养4d和24d的IAA产量比原始菌株提高了40.09%和50.15%，对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。

Screening of IAA- Producing Rhizobium Antibiotic-resistant Strain Using Microwave Mutagenesis

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,IAAA-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 8train significantly(P<0.05).