EMS Mutant Library Construction And Herbicide Resistance Individual Plants Screening In Medicago Sativa

Medicago sativa is one of the earliest cultivar and the highest economic legume forages. Here, alfalfa seeds were mutated through different concentrations of ethylmethane sulfonate(EMS), then the mutant library of alfalfa M1 and M2 were generated and identified by morphological traits. The plants with herbicide resistance were screened from mutants; The gene related herbicide resistance was cloned and expression pattern of the gene was analysed in plants with herbicide resistance. The main research results are as follows:1. Medicago sativa seeds were mutagenesised by 8 concentration of EMS. M1 and M2 generation of mutants got 1039 and 854 plants, respectively using the optimum treatment (0.8% EMS). In the population of M1 generation, there are 378 mutant plants comprised leaf (except leaf shape and leaf number,215), plant height(40), branch number(95), plant type(28) as well as other mutant plants, the plants number are, with mutation rate of 20.69%,3.85%,9.14% and 3.85% respectively. There are 30 mutat plants of seedling in M2 population, with the mutant rate of 3.51%, including leaf, branch number and plant type.These mutant materials with high genetic diversity can be used as new germplasm resources and can facilitate researching of functional genomics in alfalfa.2. Through germinating seeds with different concentration of phosphonic and glyphosate herbicide, the best screening concentration of phosphonic and glyphosate in MS medium were 8 mg/L and 600 mg/L respectively, and 80mg/L,600 mg/L in soil pots. Finally,19 herbicide resistance plants were obtained,13 of which were through screening mutants in MS medium and 6 were from soil pots.3. Full-length cDNA sequence of MsGS gene was cloned with length of 1697 bp CDS region of 1287 bp and encoding 428 amino acids. The relative molecular mass of MsGS protein is 46.9721 KD, theory of isoelectric point is 6.31 and no across the membrane structure and signal peptide structure. Using real-time quantitative PCR, the expression of MsGS gene was induced by herbicide treatment. It lay a foundation for further study of MsGS gene.