转TERF1和LeERF2双价基因旱稻及其逆境光合特性研究

Photosynthetic Characteristics of Transgenic Upland Rice with TERF1 and LeERF2 Genes under Environmental Stress

为了提高旱稻对干旱、盐及低温综合胁迫的抗性,构建了含有抗旱抗盐功能的TERF1和抗盐抗冷功能的LeERF2转录因子的双价植株表达载体;以秦爱、旱65和旱297三种旱稻品种为材料,通过农杆菌介导法将以上两转录因子转入受体材料中,获得了经PCR及Southern检测证实同时整合双价基因的T0及T1转基因植株。T1代转基因植株经不同程度NaCl、PEG、冷单一逆境处理和冷盐综合逆境处理后,仍保持着较高的净光合速率(Pn)和PSⅡ最大光化学效率(Fv/Fm),能量转换机构不易受损,有较强的光保护机制。3个品种的转基因株系对这三种胁迫的抗性均比对照有明显提高。

Transcription factors play extensive regulatory roles in responses to abiotic stresses. When plants are exposed to these stress stimuli, multiple stress-responsive genes are induced to protect plants from further injury. Recently tomato ethylene responsive factor 1 （TERF1） and Lycopersicon esculentum ethylene responsive factor 2 （LeERF2） have been successfully introduced into several plant species and achieved increasing resistance to several abiotic stresses. In this study, plant expression vector containing bivalent genes TERF1 and LeERF2 was constructed, and the two genes were transferred into three upland rice cultivars （Qin＇ai, H65, and H297） by Agrobacterium mediated transformation. The T0 and T1 plants of transgenic upland rice plants co-integrated the two transcription factor genes were identified. The resistances to drought, salt, and cold stresses in T1 transgenic upland rice were characterized. Lines Q-17, H65-12, H297- 8 were treated by 5%, 10%, and 15% PEG6000; lines Q-34, H65-12, and H297-8 were treated by 50, 100, and 150 mmol L^-1 NaCl, and lines Q-34, H65-7, and H297-12 were treated by low temperature of 8℃ and 4℃, respectively. Line Q-17 was treated by 100 mmol L^- 1 NaCl together with 4℃ - 6℃ low temperature at night for one week. Photosynthetic parameters and chlorophyll fluorescence were measured before and after the treatments. The results showed net photosynthetic rate （ Pn ） and maximum photoehemical of ΦPSⅡ efficiency （ Fv/Fm ） decreased with increasing stress levels both in transgenic lines and CK; but the range of the ehanges were wider in CK plants than in transgenic lines. When all plants were released from the stress （low temperature）, Fv/Fm value of transgenic plants could return to normal level, but CK plants couldn＇t. After cold and salt treatments, line Q-17 kept higher Fv/Fm, ΦPSⅡ , qp, and qN than CK plants. All the results indicated, under stress conditions, the photosystem Ⅱ （PSⅡ ） reaction centres in CK plants was significantly inactive or damaged, but photoinhibition in transgenic plants just to a lesser degree. So the constitutive expression of TERF1 and LeERF2 in upland rice improved the drought, salt, and cold stress tolerances, playing an extensive regulatory roles in responses to ahiotic stresses.