Efficient Transformation Of Bluegrass (P.pratensis L.) With The Salt-tolerance Genes RstB And MrstB Mediated By Agrobacterium Tumefaciens

Mature bluegrass (P. pratensis L.) seeds were used as explant for callus initiation. The basic medium was medium MSM. Under the instructed plant regeneration system, the indirect callus induction frequency was significantly higher (93-99%) than that of direct induction way. The cultivar Merit performed the best of the seven cultivars tested, with a regeneration frequency of 77.65% and a regeneration period of 16 weeks. Embryogenic calli were infected with the A. tumefaciens strain EHA105 harboring the Ti plasmid pZGl or pZG2. The transformation frequencies of the seven cultivars ranged from 0 to 6.71%. In total, 92 transgenic plants were generated. PCR, Southern-blot and Northern-blot were used for molecular test, the results showed that the rstB or mrstB was integrated into the bluegrass genome. The cultivar Merit consumed the shortest time for genetic transformationm, it was about 24 weeks. Some of the transgenic plants could live longer than non-transgenic plant, under stress of different concentration of NaCl. Physiological tests also indicated that the water-retaining capacity and the chlorophyll and proline concentrations of some salt-treated transgenic lines were higher than those of non-transgenic plants, whereas the malondialdehyde contents were lower in some transgenic plants than in non-transgenic plants.