Response To Salt And Heavy Metal Element Stress In Transgenic Lines Of Apple Carrying Exogenous AtCBF3Gene

CBF transcription factors may relate to tolerance ability of plants in abiotic stress,such as low temperature, drought and salt stress, which provides a new way for breedingplants to genetic engineering and a new direction in order to solve the problems of theapple injury under stress. In this experiment, the transgenic lines of Gala apple plantletscarrying exogenous AtCBF3gene subcultured for eight years were used to study onstability of the exogenous AtCBF3gene and analysis of the resistance indexes. Thegenetic stability of foreign genes in transgenic apple plantlets was studied by using thekanamycin resistance selection and PCR analysis. The external morphologicalcharacteristics, physiological and biochemical characteristics, and the relationship to theresistance under NaCl or CuSO4stress were studied. The effects of environment andplant growth regulator supply in the transgenic lines were evaluated. The main resultswere as follows:1Through the selection of kanamycin resistance, and the aid of the PCR techniqueto detect the foreign CBF gene in transgenic lines subcultured for eight years, the resultsshowed that exogenous nptⅡ and AtCBF3genes were preserved in a long time in theprocess of proliferation and differentiation.2Under the stress of4g/L NaCl, the plantlets injury index was significant differentbetween the transgenic lines and the non transgenic control. It could be concluded thatthe transformation of the exogenous AtCBF3gene in apple increased the salt toleratingability in plant growth in some extent.3Under4g/L NaCl stress situation, in the same time, the relative conductance of thetransgenic lines was significant lower compared to that of the non transgenic control. Theresults showed that the transformation of the exogenous AtCBF3gene into apple played acertain role in maintaining the stability of the cell membrane.4Under the stress of5mg/L copper, the rooting rate of transgenic lines wassignificant higher compared to that of the non transgenic control. With the increasing ofcopper to10mg/L, the callusogenesis rate of transgenic lines was significant highercompared to that of the control. The results showed that the transformation of the exogenous AtCBF3gene in apple increased the heavy mental element tolerating ability inplant growth in some extent.5When the concentration of copper reached50mg/L or higher, the relativeconductance of the transgenic lines was significant lower compared to that of the control.The expression of exogenous AtCBF3genes protected the cell membrane of appleplantlets from harming under the stress.6The transgenic lines of apple planted in the greenhouse showed leaf senescence,dwarf, and growth stop when the winter was coming. It showed that the expression ofexogenous AtCBF3genes in apples regulated the growth and development of the appleplants.7The growth of the transgenic lines could be resumed by spraying2mg/mL GA3.