亚精胺对水分胁迫下白三叶脯氨酸代谢、抗氧化酶活性及其基因表达的影响  

Effects of spermidine on proline metabolism,antioxidant enzyme activity and gene expression in white clover leaves under water stress

作　　者：李州[1] 彭燕[1] 

机构地区：[1]四川农业大学动物科技学院草业科学系,四川雅安625014

出　　处：《草业学报》2015年第4期148-156,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(NSFC31372371);十二五农村领域国家科技计划课题(2011BAD17B03)资助

摘　　要：以广泛栽培的"拉丁诺"白三叶为供试材料,对其在不同水分胁迫处理下叶片相对含水量、活性氧成分、膜脂过氧化产物、抗氧化酶活性、脯氨酸含量及其代谢酶活性等生理指标进行测定,并利用RT-PCR技术分析4种抗氧化酶基因在不同胁迫条件下的表达特性,分析外源亚精胺缓减水分胁迫的效应。结果表明,水分胁迫下白三叶叶片相对含水量逐步降低,活性氧和丙二醛含量不断升高,外源亚精胺能显著提高胁迫下叶片相对含水量,有效降低活性氧和膜脂过氧化产物的积累;外源亚精胺使水分胁迫下白三叶抗氧化酶活性和基因表达量发生改变,提高了水分胁迫下白三叶叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化酶(APX)基因的表达从而提高抗氧化酶活性,缓解了水分胁迫造成的氧化胁迫伤害;外源亚精胺提高了脯氨酸合成代谢关键酶Δ’-吡咯啉-5-羧酸合成酶(P5CS)和分解代谢关键酶脯氨酸脱氢酶(ProDH)活性,促进了水分胁迫下脯氨酸的代谢,但对脯氨酸合成代谢鸟氨酸途径中关键酶——鸟氨酸转氨酶(OAT)没有影响。外源亚精胺能有效提高白三叶的抗水分胁迫能力,这与亚精胺诱导了胁迫下白三叶抗氧化酶基因表达,提高抗氧化酶活性和促进脯氨酸的代谢从而减轻由水分胁迫造成的氧化伤害、稳定了细胞膜系统及提高渗透调节能力密切相关。The effects of spermidine （Spd）on relative water content,reactive oxygen,membrane lipid preoxi-dation,antioxidant enzyme activity and proline metabolism were studied in white clover （Trifolium repens ） leaves,cultivar ‘Ladino’.The expression patterns of four different antioxidant enzyme genes were analyzed u-sing semi-quantitative RT-PCR under different water stress.Under water stress,relative water content grad-ually declined whereas reactive oxygen and malondialdehyde （MDA）content increased.Exogenous Spd signifi-cantly improved relative water content and effectively reduced the accumulation of reactive oxygen and MDA. Exogenous Spd changed antioxidant activities and gene expression pattern under different water stress regimes and increased expression of superoxide dismutase （SOD）,catalase （CAT）,peroxidase （POD）and ascorbate peroxidase （APX）genes to improve antioxidant enzyme activities,reducing water stress injury.Exogenous Spd accelerated proline catabolism and biosynthesis from the glutamate pathway during water stress although it had no effect on the ornithine pathway of proline biosynthesis.The results suggested that exogenous Spd can effec-tively improve water stress tolerance of white clover associated with the improving antioxidant enzyme activi-ties,enhancing expression of genes encoding antioxidant enzymes and accelerating proline metabolism.

关 键 词：白三叶 亚精胺 水分胁迫 抗氧化酶 基因表达 脯氨酸 

分 类 号：S541.2[农业科学—作物学]