Regeneration of transgenic loblolly pine expressing genes for salt tolerance

Abstract

Salinity stress is one of the most serious factors limiting the distribution and productivity of crops and forest trees. The detrimental effects of salt on plants are a consequence of both a water deficit resulting in osmotic stress and the effects of excess sodium ions on critical biochemical process. A novel approach to improve salt tolerance has been established by using the technology of plant genetic transformation and using loblolly pine (Pinus taeda L.) as model plant. Mature zygotic embryos of loblolly pine were infected withAgrobacterium tumefaciens strain LBA 4404 harbouring the plasmid pBIGM which carrying the mannitol-1-phosphate dehydrogenase (Mt1D) and glucitol-6-phosphate dehydrogenase (GutD). Organogenic transgenic calli and transgenic regenerated plantltes were produced on selection medium containing 15mg/L kanamycin and confimed by Southern blot analysis of genomic DNA. Salt tolerance assays demonstrated that the salt tolerance of transgenic calli and regenerated plantlets were increased. These results suggested that an efficientAgrobacterium tumefaciens-mediated transformation protocol for stable integration of foreign genes into loblolloy pine has been developed and this could be useful for the future studies on engineering breeding of conifers.