紫外照射对葡萄果实莽草酸途径相关基因表达的影响

Effects of Ultraviolet Radiation on Expression of Shikimate Pathway-Related Genes in Grape (Vitis vinifera L.) Berries

本文以花后11周的‘赤霞珠’葡萄果实为试材,应用荧光实时定量PCR技术,研究6种剂量的UV-A、UV-B和UV-C照射对莽草酸途径及后分支酸途径关键酶基因表达量的影响。结果表明,这些基因在转录水平上对紫外诱导的响应不同步,且有照射剂量的依赖性。一定剂量的紫外照射可显著地诱导莽草酸途径的大部分基因和后分支酸途径的VvCM-1、VvCM-2和VvAS的表达;高于或低于该剂量,表达量明显降低。不同基因对紫外诱导的响应也存在差异:3种类型紫外线对莽草酸途径入口酶的两个同源基因VvDAHPS-1和VvDAHPS-2的诱导效应均最为显著。随紫外波长减小,这两个基因受诱导表达的量有所下降。VvSK和VvCS的表达只受1.2kJ·m-2UV-A的诱导,而不受UV-B和UV-C照射的影响,在后分支酸途径中紫外对VvCM-1表达的诱导作用明显大于VvCM-2和VvAS。

The present study investigated the effects of radiation of UV-A,UV-B and UV-C,respectively,with six doses on the expression of the genes in shikimate pathway and post-chorismate pathway in grape （Vitis vinifera cv. ＇Cabernet Sauvignon＇） berries at 11 weeks after full bloom,by means of real-time PCR. The results showed that the transcript abundance of these genes in response to UV radiation was dose-dependent,but not synchronized. A certain dose of UV radiation could significantly induce the expression of most of genes in shikimate pathway and the expression of VvCM-1,VvCM-2 and VvAS in post-chorismate pathway,but gene expression was reduced when higher or lower radiation was applied. Various genes showed different responses to the same type of UV radiation. Three types of UV all most significantly induced transcript abundances of both VvDAHPS-1 and VvDAHPS-2 that encode the entry isozymes of shikimate pathway,whereas short wavelength UV suppressed the accumulation of their transcripts. The expression of VvSK and VvCS was promoted only by UV-A radiation of 1.2 kJ·m^-2,but not by UV-B and UV-C radiation. In post-chorismate pathway,the transcrip-tional induction of VvCM-1 by UV radiation was more significant than that of either VvCM-2 or VvAS.