转色期苯丙噻二唑处理对‘霞多丽’葡萄果实氨基酸构成及其降解代谢的影响

Effect of Benzothiadiazole Treatment during Veraison on Amino Acid Composition,Degradation and Metabolism in‘Chardonnay’Grape

为探究苯丙噻二唑(benzothiadiazole,BTH)处理对葡萄生长过程中果实氨基酸积累及其降解代谢的影响,以‘霞多丽’葡萄为实验植株,果实转色期喷施50 mg/L BTH,花后60 d开始每10 d采集1次样品直至果实成熟(花后110 d),使用高效液相色谱法、氨基酸自动分析仪、固相微萃取联合气相色谱-质谱联用仪分别分析果实的葡萄糖、果糖、蔗糖、有机酸和氨基酸含量,以及氨基酸降解代谢相关酶活性和相应香气产物。结果表明:谷氨酸、精氨酸和脯氨酸是‘霞多丽’葡萄果实的主要氨基酸,BTH处理可促进果实氨基酸积累,抑制果实葡萄糖、果糖和蔗糖生成,提高成熟果实的酒石酸和柠檬酸含量,降低苹果酸含量;同时,BTH处理抑制了果实游离态支链脂肪族香气化合物的生成,增强了成熟葡萄的氨基酸转移酶(aminotransferase,AT)、醇酰基转移酶(alcohol acyltransferase,AAT)和丙酮酸脱羧酶活力,改变了氨基酸总量与乙醇脱氢酶活力的相关性及AT和AAT活力与单糖和有机酸含量的相关性,进而影响了氨基酸代谢香气物质的生成。研究结果可为BTH调控葡萄品质的应用提供理论指导及实践依据。

In order to explore the effect of benzothiadiazole(BTH)treatment on amino acid accumulation,degradation and metabolism during the growth of grape fruits,‘Chardonnay’grape berries at veraison were sprayed with BTH at 50 mg/L and plucked once every 10 d from the next day(60 d after flowering)until maturity(110 d after flowering).The contents of glucose,fructose,sucrose,organic acids and amino acids,as well as enzyme activities related to amino acid degradation and metabolism and the resulting aroma products were analyzed by high performance liquid chromatography(HPLC),an automatic amino acid analyzer and solid phase microextraction combined with gas chromatography-mass spectrometry(SPME-GC-MS).The results showed that glutamic acid,arginine and proline were the major amino acids in‘Chardonnay’grape.BTH treatment promoted the accumulation of amino acids,inhibited the production of glucose,fructose and sucrose,increased the contents of tartaric acid and citric acid,and reduced the content of malic acid in mature grapes.Moreover,BTH treatment inhibited the production of free branched aliphatic aroma compounds,and enhanced the activities of aminotransferase(AT),alcohol acyltransferase(AAT),and pyruvate decarboxylase(PDC).Meanwhile,it changed the correlation between total amino acids and alcohol dehydrogenase(ADH)activity,and the correlation between AT and AAT activity and monosaccharides and organic acids content,which in turn affected the production of aroma substances from amino acid metabolism.These results provide theoretical guidance and a practical basis for the application of BTH in controlling grape quality.