Molecular Detection And Evaluation Of Stress Tolerance In The Transgenic Poplars

Poplar is an important commercial timber tree species of short rotation for industrial purposes,with fast growth,informative varieties and widely distribution.It has played a key role in conservation of water and soil and in maintenance of ecology balance.However poplar breeders have mostly been aiming to improve the growth rate and wood product consequently resulted in the poor adaptation and resistance.The present cultivars,therefore,can't completely exert their roles in the field of arid, semiarid saline-alkali and waterlogged environment.The situation had limited the development of ecological and economic construction.But,the development of genetic engineering provided an effective alternative approach to create the new transgenic poplar germplasm with stress resistance within a short time.In this study molecular detection and evaluation of stress tolerance in greenhouse,field and different circumstance of stress tolerance for the transgenic poplar with drought,saline-alkali and waterlogging tolerance gene.The major results and conclusions are described as follows.1.Molecular detection and evaluation of drought tolerance in the transgenic poplars(Populus alba×p.glandulosa)with SacB.The transgenic poplars with SacB were detected by the molecular ways of Southern blotting and realtime-PCR,and the result showed that 28 of 53 clones was positive,implying the SacB was integrated into the genome of poplars and expressed.By taking drought stress on transgenic poplars in the greenhouse,the result indicated that the leaves of control plant became yellow and fall off,but the transgenic ones were fine.The degrees of response to drought stress were apparently different within the transgenic clones and the yield and biomass of over ground parts of T23 and T72 had significance difference with comparison to the control plant.The levan produced by the expression of SacB was detected and the result showed there was more levan in leaves of transgenic plant while little in control plant.This implied that the enhancement to drought tolerance may be caused by the accumulation of levan.Taking the normal transgenic plants to the nursery and measuring its growth traits,photosynthetic parameter,and the result showed that the height and basal stem of 5 transgenic strains were superior than control plant.The interval of leaf,specific leaf weight and the water utilization efficiency of transgenic plants were higher than control plant.In order to investigate growth performance of transgenic plant in drought area, contrasting test forest of transgenic poplar in drought area of Inner Mongolia was established,the result show that the yield of line 9 was higher than the control in line12. The result above showed that the transgenic poplars enhanced the drought tolerance by over expressing the SacB.2.Molecular detection and evaluation of salt tolerance in the transgenic poplars(P.alba×P.berolinensis Dipple.)with JERFs gene.The transgenic poplars with JERFs were detected by the molecular ways of PCR amplification,Southern blotting and realtime-PCR,and the result showed that 13 of 18 clones was was positive, implying the JERFs was integrated into the genome of poplars and expressed.By taking salt stress on transgenic poplars in greenhouse,the result indicated that with density increase and treatment time lasting,degree of inhibition of transgenic plant was lower than control plant;content of proline and sodium ion in leaves of transgenic poplars increase while content of MDA decrease,on the contrary to control plant,that suggest that expression of transgenic poplars can lead content of proline increase and enhance stability of cellular membrane,and then enhance its salt tolerance ability.Taking the normal transgenic plants to the nursery and measuring its growth traits,photosynthetic parameter,the result showed that height and basal stem of transgenic strains were superior than control plant.The interval of leaf of transgenic plants were shorter than control plant.,specific leaf weight and the water utilization efficiency of transgenic plants were higher than control plant.In order to investigate growth performance of transgenic plant in saline area,contrasting test forest of transgenic poplar in saline area of saline lands of seashore and saline lands of inland,the result show that the yield of line 4 was higher than the control in line 8.The result above showed that the transgenic poplars enhanced the salt tolerance by overexpressing the JERFs.3.Molecular detection and evaluation of waterlogging tolerance in the transgenic poplars(P.alba×p.glandulosa)with vgb gene.The transgenic polars with vgb were detected by the molecular ways of PCR amplification,Southern blotting and realtime-PCR,and the result showed that 24 of 73 clones was was positive,implying the vgb was integrated into the genome of poplars and expressed.By taking waterlogging stress on transgenic poplars in greenhouse,the result indicated that most leaves were wilting 2 days later and leaf abscission of inferior part appear obviously 4 days later,and aerial parts darkening then were dead 10 days later,and the death rate was 66.7%of the control plant,The growth inhibiting degree and the decreased degree of transgenic plants was lower than control plants under waterlogging stress,This implied that promote the growth and the enhancement to waterlogging tolerance may be caused by the accumulation of chlorophyll.Taking the normal transgenic plants to the nursery and measuring its growth traits,the result showed that height and basal stem of transgenic strains were superior than control plant.The interval of leaf and specific leaf weight and the water utilization efficiency of transgenic plants were higher than control plant.In order to investigate growth performance of transgenic plant in waterlogging area,contrasting test forest of transgenic poplar in Minluo of Hunan province,the result show that the yield of line 3 was higher than the control.The result above showed that the transgenic poplars enhanced the waterlogging tolerance by over expressing the vgb.By taking molecular detection on poplar resistant plant with gene transmitting of SacB,JERFs and vgb and evaluating its stress tolerance in greenhouse,growth trait in field,growth performance under adversity,a new transgenic poplar with modified stress tolerance was obtained and stress tolerance evaluation system was established,which will have some good effect on construction of environment and development of economy of drought area,saline-alkaline area and waterlogged area as well as on genetic engineering breeding of poplar stress tolerance.