红蓝光对茉莉花香气成分及相关基因表达的影响

Effect of red and blue light on the aroma components and gene expression in Jasminum sambac

茉莉花茶在窨制过程中,通过吸附茉莉花散发的香气而形成其独特的香气品质,茉莉花的香气质量直接决定着茉莉花茶的品质.以双瓣茉莉花为供试材料,以白光为对照组,设置红光、蓝光为处理组,采用静态顶空-气相色谱/质谱(HS-GC/MS)技术分析茉莉花开放过程中香气成分,并通过实时荧光定量PCR技术,检测香气合成相关基因的表达量.结果显示,茉莉花主要香气成分是酯类、醇类、萜烯类化合物.红光和蓝光处理对茉莉花香气成分主要的类型无影响,其中红光可显著增加香气化合物的含量,而蓝光会抑制香气化合物的积累,红光和蓝光均可使一些化合物的释放高峰期提前.经过红光和蓝光分别处理后,茉莉花主要发生变化的香气物质包括水杨酸甲酯、乙酸苄酯、α-法呢烯、芳樟醇等化合物,且红光处理与蓝光处理相比较,前者的香气化合物含量增加的幅度明显高于后者.实时荧光定量PCR结果表明,萜类合成途径中相关酶基因的相对表达量在红光作用下均呈上升趋势,而在蓝光作用下的相对表达量的变化各异;苯丙烷类合成限速酶基因JsPAL在红光作用下表达量略有上升,而蓝光下,前期表达量下降后期上升,JsSAMT基因在红光和蓝光作用下均上调,但在红光中表现更显著.本研究从物质水平和分子水平分析红蓝光对茉莉花开放过程中香气成分的影响,可为茉莉花中香气物质的形成机理和开发利用等研究奠定基础.(图5表2参32)

In the process of scenting,the jasmine tea forms its unique aroma by absorbing the aroma of the jasmine flower.The aroma quality of the jasmine flower directly determines the quality of jasmine tea.In this study,Jasminum sambac was grown under different light conditions-white light as the control and red and blue light as the treatment groups.The aroma contents of the jasmine flowers grown under different light treatments were measured by headspace gas chromatography-mass spectrometry(HS-GC-MS).The expression levels of the aroma-related genes were measured by real-time quantitative PCR(RT-qPCR).The main aroma components were esters,alcohols,and terpenes,and the main aroma components were not affected by the light treatments.The total contents of the aroma compounds were significantly higher in the red light treatment but were inhibited by the blue light treatment.The peak contents ofα-farnesene and linalool were during the opening stages in red and blue light.Compared to the control,the red and blue light treatments significantly influenced the contents of methyl salicylate,benzyl acetate,α-farnesene,and linalool,but the blue light effects were not as strong as the red light effects.RT-qPCR showed that the relative expression of the genes in the terpenoid synthesis pathway was increased under red light,while the expression patterns under blue light varied.The expression of JsPAL in the phenylpropane synthesis pathway was slightly increased under red light,but under blue light,expression was initially decreased.The JsSAMT gene was up-regulated under red and blue light,but the difference was greater in red light.This study analyzed the effects of red and blue light on the aroma components during jasmine opening and provides a foundation to develop jasmine aroma components.