AsA-GSH循环参与2,3-丁二醇、2R,3R-丁二醇诱导后匍匐翦股颖的抗病反应

用250 μmol/L的2,3-丁二醇(2,3-BD)与100 μmol/L的2R,3R-丁二醇(2R,3R-BD)注射至匍匐翦股颖根部后接种立枯丝核菌,诱导匍匐翦股颖对褐斑病的抗性。测定两诱导剂处理对立枯丝核菌发病率的影响,分析诱导后匍匐翦股颖叶片抗坏血酸-谷胱甘肽循环中关键酶活性及氧化还原水平变化情况,确定2,3-BD与2R,3R-BD在诱导匍匐翦股颖抗病性过程中,抗坏血酸-谷胱甘肽循环的变化及其与抗病性的相关性。结果表明,2,3-BD与2R,3R-BD处理匍匐翦股颖后明显降低接菌后的病叶率,同时叶片抗坏血酸过氧化物酶(APX)活性增幅低于对照,谷胱甘肽还原酶(GR)活性提高,还原型抗坏血酸(AsA)含量呈前期减少后期增加趋势,脱氢抗坏血酸(DHA)含量在第1,9天出现两次高峰,与对照相比显著提高,且两处理的AsA/DHA在第5天达到最大值,分别为对照的5.0,3.4倍,还原型谷胱甘肽(GSH)含量显著提高,并且两处理的GSH与氧化型谷胱甘肽(GSSG)比值在第9天达到最大值,分别为对照的2.34,1.66倍。2,3-BD与2R,3R-BD诱导匍匐翦股颖抗褐斑病的过程中,抗坏血酸-谷胱甘肽循环维持较高效率参与植物抗病反应。

Involvement of the ascorbate-glutathione cycle in resistance of creeping bentgrass to Rhizoctonia solani induced by 2,3-butanediol and 2R,3R-butanediol

The compounds 2,3-butanediol (BD)and 2R,3R-BD can cause creeping bentgrass to show increased resistance against Rhizoctonia solani .To evaluate the mechanisms of this induced resistance,we determined the activities of antioxidant enzymes in the ascorbate-glutathione cycle and the redox states of various antioxi-dant compounds in leaves of creeping bentgrass that were injected with 250 μmol/L 2,3-BD and 100 μmol/L 2R,3R-BD before inoculation with R.solani.The 2,3-BD and 2R,3R-BD treatments significantly decreased the disease incidence in creeping bentgrass plants inoculated with R.solani and increased the activities of gluta-thione reductase (GR)and ascorbate peroxidase (APX).However,the increase in APX activity was smaller than that in the control (no BD).In the plants treated with 2,3-BD and 2R,3R-BD,the ascorbic acid (AsA) content decreased at an early stage and increased at a later stage after inoculation,while the content of de-hydroascorbic acid (DHA)peaked at 1 and 9 d after inoculation at levels significantly higher than those in the control.The AsA/DHA ratios of plants treated with 2,3-BD and 2R,3R-BD reached a maximum at 5 days af-ter inoculation (5.0 and 3.4 times the AsA/DHA ratio in the no-BD control at 5 d after inoculation,respective-ly).In plants treated with 2,3-BD and 2R,3R-BD,the glutathione (GSH)content significantly increased and the GSH/GSSG ratios peaked at 9 days after inoculation at 2.34 and 1.66 times that in the no-BD control,re-spectively.These results suggest that in creeping bentgrass,the resistance against R.solani induced by 2,3-BD and 2R,3R-BD involves the ascorbate-glutathione cycle,which maintains efficient metabolism and participates in the plant disease resistance response.