盐胁迫下匍匐翦股颖抗氧化酶活性及基因表达机制研究

为研究匍匐翦股颖在盐胁迫下抗氧化酶活性与基因表达的影响机制,模拟盐胁迫条件,用0 mol/L(CK),0.2 mol/L的NaCl溶液对两种不同耐盐性的匍匐翦股颖Penncross和SeasideⅡ进行处理,测定了超氧化物歧化酶(SOD),过氧化氢酶(CAT),抗坏血酸过氧化物酶(APX)和过氧化物酶(POD)活性;用同源克隆的方法克隆了匍匐翦股颖CytSOD,FeSOD,CAT,APX,POD的部分片段,并设计了5个基因的qRT-PC引物,对5个抗氧化酶基因表达量进行了荧光实时定量测定,分析了两种不同耐盐性的匍匐翦股颖在盐胁迫条件下,抗氧化酶活性与基因表达的变化规律。结果表明,盐胁迫对两种不同耐盐性的匍匐翦股颖抗氧化酶活性和基因表达的影响不同,在盐胁迫初期,盐敏感的Penncross SOD活性比耐盐的SeasideⅡ高,盐处理中、后期Penncross SOD活性快速下降,SeasideⅡSOD活性下降慢而且能保持相对稳定,在这一阶段SeasideⅡSOD活性显著高于Penncross;CAT,APX和POD活性随着盐处理的延长,酶活性增加,Penncross CAT和APX活性低于SeasideⅡ,POD活性两者差异不大。盐胁迫下,Penncross CytCu/ZnSOD,CAT、APX 和POD表达量上调,而FeSOD下调;SeasideⅡ5种抗氧化酶基因表达量上调,CytCu/ZnSOD,FeSOD,CAT和APX的表达量显著高于Penncross,而POD表达量差异不大。两种匍匐翦股颖CytCu/ZnSOD、CAT、APX和POD表达量变化与酶的活性变化较一致,而盐敏感的FeSOD的表达量变化与SOD活性变化不一致。

Antioxidant enzyme activity and gene expression in creeping bentgrass under salt stress

The aim of this research was to investigate the antioxidant enzyme activity and gene expression mech-anisms in creeping bentgrass (Agrostis stolonifera )under salt stress.Two different salt-resistant creeping bentgrass cultivars,Penncross and SeasideⅡ,were treated with 0 (CK)and 200 mmol/L NaCl solutions.The activities of superoxide dismutase (SOD),catalase (CAT),ascorbate peroxidase (APX)and peroxidase (POD)were measured.The qRT-PCR primers for the CytSOD ,FeSOD ,CAT,APX and POD genes of creeping bentgrass were designed using partial gene segments,which were identified with homology cloning techniques.The gene expression levels of CytSOD ,FeSOD ,CAT,APX ,and POD were measured and the ac-tivities of antioxidant enzymes and gene expression of the two different salt-resistant creeping bentgrass culti-vars were analyzed.Salt stress had different effects on antioxidase activities and gene expressions on the two creeping bentgrass cultivars.At the beginning of salt stress,SOD activity of salt-sensitive Penncross was high-er than that of salt-resistant SeasideⅡ.However,in the later stages of the treatment,the activity of Penncross SOD declined dramatically while the activity of SeasideⅡ SOD declined slowly and tended to be relatively sta-ble,during which the activity of Seaside Ⅱ SOD was significantly higher than Penncross.The activities of CAT,APX and POD increased with salt treatment.The CAT and APX activities of Penncross were lower than those of SeasideⅡ,while POD activity was not different.Under the salt treatment,CytSOD ,CAT,APX and POD expression of Penncross increased while FeSOD expression decreased.For SeasideⅡ,gene expression of the five antioxidases increased;CytSOD ,FeSOD ,CAT and APX gene expression were significantly higher in SeasideⅡ than Penncross,but POD was not different.The relative expression levels of CytCu/ZnSOD ,CAT, APX and POD genes changed consistently with enzyme activities,but the relative expression level of the Fe-SOD gene in Penncross was not consistent with enzyme activity.