Effects Of Region,Training System And Bunch Light Condition On Norisoprenoids Production In Grapes And Wines

Norisoprenoids are an important contributor to varietal aroma of grape berries.They are also key volatile constituents of wines.This study aimed to study the effects of three training systems,regional factors,bunch exposure and shading treatments on the accumulation of norisoprenoids of Vitis vinifera cv.Cabernet Sauvignon grape berries and wines produced at the northern foot of Mount Tianshan.The results were shown as follows:By comparison of two regions in China(Changli(CL)in east,and Gaotai(GT)in west),we found that:Carotenoid biosynthesis was significantly enriched at pre-veraison and at veraison.The accumulation of carotenoids was closely related to the co-expression of VvDXS and VvGGPPS,as well as high expression of VvPSY.As for the down-stream pathway of carotenoid metabolism,The metabolic flow preferred in norisoprenoid biosynthesis in the CL-produced grapes,while it distributed more to ABA synthetic metabolism in the GT-produced grapes.The genes involved in the biosynthesis and signal transduction of ethylene and ABA were up-regulated at both pre-veraison and veraison in the GT grapes in comparison with CL grapes,which explains why Cabernet Sauvignon grape berries in the GT region begin to turn color one-week earlier than thos in the CL.We inferred that less rainfalls and strong sunshine should be main reason causing the up-regulation of ripening-related genes in GT grapes.The effect of three training systems on norisoprenoid production was investigated.The results showed that:different training systems significantly influenced the accumulation of carotenoids and norisoprenoids,as wellas the expression of the related genes.This influence was also different from carotenoid components and norisoprenoid compounds.Among these compounds,?-carotene and two kinds of ?-damascenone were significantly accumulated.Variation in rainfall and temperature in two vintages should be key factors affecting the differential accumulation of carotenoids and norisoprenoids in 2011 and 2012.Bunch light exposure decreased the accumulation of carotenoids and norisoprenoids in grape berries.Not all carotenoids and norisoprenoids were influenced by bunch light treatments,?-carotene and(E)-?-damascenone were significantly effected by these treatments.Vintage factors,including PAR,temperature and rainfall may related with norisoprenoids differences in grapes and related wines.Results of different levels of berry light exclusion at various developmental stages showed that:light exclusion in different berry development stages changed the bunch micro-environment.These treatments also decreased the carotenoids and norisoprenoids accumulation of grape berries,especially?-carotene,(E)-?-damascenone and(Z)-?-damascenone.Light exclusion in fruit setting stage significantly decreased the expression of norisoprenoids metabolism related genes.We targeted several key genes that response with berry exposure/shading treatments from about 24,000 genes annotated in grape berries by use of Bioconductor project and data mining methods.They are:a),auxin-induced protein 5NG4 in cluster bagging of green period and control;b),aspartate aminotransferase gene and CCD1 from cluster bagging at the initiation of veraison and control;c),PP2C58 and WRKY transcription factor 41 in leaf-remove,leaf-move treatments in veraison and control;d),CCD1 of cluster bagging in green period and in veraison treatments and control.We also compared three methods(Pearson correlation,Partial correlation with dynamic and static Gaussian Graphical Models(GGM))of gene co-expression network construction,and the results showed that compared with network based on Pearson coefficients,networks from GGM resulted in a better and more vivid visualization of interactions and relationships of genes.To summarize,above results provide basic understanding of influence of regional factors,berry exposure and shading treatments on fruit zone microclimate factors,and their relationships with norisoprenoids metabolism.This will provide basis for optimize viticulture treatments and promote the quality of berry flavors and wines in Northern foot of Mount Tianshan.