干旱胁迫下 rolB 基因对杜梨生长和抗旱性的影响

Effect of rolB gene on growth and drought resistance of Pyrus betulifolia under drought stress

以转rolB基因杜梨和非转基因杜梨杜梨组培苗为试材,研究轻度(土壤相对含水量50%~55%,T2)、中度(土壤相对含水量40%~45%,T3)和重度(土壤相对含水量30%~35%,T4)干旱胁迫对植株生长、活性氧含量、MDA含量和抗氧化酶活性的影响,以土壤相对含量水70%~75%处理(T1)为对照,旨在明确rolB基因对转基因杜梨抗旱性的影响,为今后选育抗旱性强的杜梨种质资源提供依据。结果表明:胁迫处理前(T0)转rolB基因杜梨的根冠比、叶片中总叶绿素、类胡萝卜素含量和CAT活性显著高于非转基因杜梨,活性氧(O-2、H 2O 2)、MDA含量和SOD、POD活性无显著差异。与对照(T1)相比,轻度胁迫(T2)对转基因杜梨总鲜重、总干重、活性氧和抗氧化酶活性无显著影响,显著降低了非转基因杜梨总鲜重、总干重、根冠比。中度(T3)、重度(T4)胁迫显著降低了2株系总鲜重、总干重、根冠比,而O-2、H 2O 2含量和SOD、POD、CAT活性显著增加。但是,中度和重度干旱胁迫下转基因杜梨的活性氧、丙二醛含量显著低于非转基因杜梨,SOD、POD、CAT活性和叶片相对含水量显著高于非转基因杜梨。由此可知,rolB基因提高了转基因植株的根冠比、叶片中色素含量,增强了干旱胁迫下抗氧化酶活性,降低活性氧和MDA的积累,缓解了干旱对转基因杜梨生长的抑制作用。

Tissue culture seedlings of rolB gene and non-transgenic of Pyrus betulifolia under drought stress were used as test materials to study the effects of mild(soil relative water content 50%-55%,T2),moderate(soil relative water content 40%-45%,T3)and severe(soil relative water content 30%-35%,T4)drought stress on plant growth,active oxygen content,MDA content and antioxidant enzyme activity.The aim of this study was to determine the effect of rolB gene on drought resistance of transgenic P.betulifolia with 70%-75%soil relative content water(T1)as control,and to provide a basis for future breeding of germplasm resources with strong drought resistance.The results showed that the ration of root to stem,total chlorophyll content,carotenoids content and catalase(CAT)activity of transgenic plant were significantly higher than non-transgenic P.betulifolia before drought stress,the contents of reactive oxygen species(O-2,H 2O 2)and MDA were not significantly different from the activities of SOD and POD.Compared with control(T1),mild stress(T2)had no significant effects on total fresh weight,total dry weight,active oxygen species and antioxidant enzyme activities of transgenic P.betulifolia,the total fresh weight,total dry weight and root-shoot ratio of non-transgenic P.betulifolia were significantly reduced.Moderate(T3)and severe(T4)stress significantly decreased the total fresh weight,total dry weight and root-shoot ratio of 2 lines,while the contents of O-2,H 2O 2 and activities of SOD,POD and CAT were significantly increased.However,the contents of active oxygen and malondialdehyde in transgenic P.betulifolia were significantly lower than those in non-transgenic P.betulifolia under moderate and severe drought stress,and the activities of SOD,POD,CAT and relative water content in leaves were significantly higher than those in non-transgenic P.betulifolia.In conclusion,rolB gene increased the root to shoot ratio and pigment content in leaves of transgenic plants,enhanced the activity of antioxidant enzymes under drought stress,decreased the accumulation of reactive oxygen species and MDA,and alleviated the inhibitory effect of drought on the growth of transgenic P.betulifolia.