转果聚糖合成关键酶基因多年生黑麦草的获得及抗旱性的提高

Transformation of Lolium perenne with a fructan:fructan 1-fructosyltransferase gene from Agropyron cristatum and enhancement of drought tolerance in transgenic plants

以多年生黑麦草(品种卡特)胚性愈伤组织为转化受体,利用农杆菌介导的遗传转化方法将冰草果聚糖:果聚糖-1-果糖基转移酶基因(Ac1-FFT)导入黑麦草中,对再生植株喷洒basta溶液和PCR法检测,共获得18个阳性株系,RT-PCR结果表明,该基因在转基因黑麦草中正常表达。转基因黑麦草株系中的可溶性总糖含量和果聚糖含量明显高于对照植株,耐旱性提高,干旱胁迫6d时其相对含水量和叶绿素含量明显高于对照植株,且下降速度慢,但其电解质渗漏率和丙二醛含量显著低于对照植株,复水后很快复原,而对照植株无法恢复,说明转基因植株中由于干旱处理发生的损伤是可逆的,而对照植株中的损伤是非可逆的。以上结果表明,转基因黑麦草中Ac1-FFT的表达及果聚糖合成可能是其耐旱性提高的最重要原因。

Ac1-FFT（fructan：fructan 1-fructosyltransferase） cloned from Agropyron cristatum was transformed into embryogenic callus lines of Lolium perenne using an Agrobacterium mediated method.Transgenic plants were analyzed by basta spraying and PCR amplification.In total,18 independent transgenic lines were obtained with significantly improved drought tolerance.RT-PCR analysis showed that Ac1-FFT expressed strongly in transgenic L.perenne plants but not in control plants.Water soluble carbohydrate and fructan contents of Ac1-FFT transgenic L.perenne were significantly higher than those in control plants.Relative water content and chlorophyll content were significantly higher,while electrolyte leakage and malondialdehyde（MDA） content were significantly lower in the Ac1-FFT transgenic L.perenne than in control plants for 6 days after drought treatment.Relative water content,chlorophyll content,electrolyte leakage and MDA content were restored to their original levels after rewatering in Ac1-FFT transgenic plants but not in control plants.This suggests that the damage to Ac1-FFT transgenic plants was reversible but it was not in control plants.Ac1-FFT expression and fructan biosynthesis may play an important role in improving drought tolerance of Ac1-FFT transgenic L.perenne.