Study On The Difference Of Carotenoid Synthesis In Different Grape Varieties

Carotenoids not only play an indispensable role in plant growth and development,but also benefit human health.In plants,carotenoids are mainly found in plant chloroplasts and color bodies.In grape,carotenoids are important factors that determine the appearance and intrinsic quality of grape skins.In order to clarify the changing rules of carotenoid content in fruit development of different color grape varieties,to understand the tissue expression characteristics of genes related to carotenoid metabolism in different color grape varieties,and to explore the mechanism of related genes in carotenoid metabolism,In this study,the horizontal and vertical diameters,single fruit weight,fruit firmness,TSS,TA,total anthocyanin,and chlorophyll a/b were measured during the growth and development of 4 yellow-green grape varieties,3 purple-red grape varieties,and 3 purple-black grape varieties.Determination of total carotenoid content and expression analysis of 10 carotenoid metabolism-related genes.The characteristics of morphological and physiological indexes and tissue expression during the development of three different color varieties of grape fruits were clarified,in order to provide further theoretical data for the further study of the molecular condition regulation mechanism of carotenoid anabolism in different colors and different varieties of grape.The main findings of this study are as follows:1.With the growth and development of fruits,the total carotenoid content of different color grape varieties showed a decreasing trend,and the yellow-green varieties had the highest carotenoid content when the fruits matured.2.With the growth and development of fruits,the anthocyanin content of different color grape varieties was different,and almost no anthocyanins in yellow-green varieties.However,in the purple-red and purple-black varieties,the content gradually increased.From the color changing stage to the mature stage,the anthocyanin content of purple-black grape varieties was higher than that of purple-red varieties.3.With the development of grape fruits,the contents of chlorophyll a and b in different color grape varieties gradually decreased,the chlorophyll a,b content were highest in the yellow-green varieties at maturity.The ratio of chlorophyll a/b content during fruit development is maintained at about 2.0.4.By exploring the expression patterns of genes related to carotenoid metabolism,the results showed that there are certain differences in the expression patterns of 12 carotenoid metabolism-related genes in 3 different color grape fruits.Among 4 yellow-green grape varieties and 3 purple red varieties,the expression levels of VvDXR,VvDXS2,VvVDE and VvNCED1 were almost all gradually decreased,and among the 3 purple-black grape varieties,the expression levels of VvDXR,VvDXS1,VvDXS2,and VvNCEDl gradually decreased,which was consistent with the accumulation of carotenoids,indicating that they may be the key genes that limit the accumulation of carotenoids in grape fruits.But the expression of VvPSY2r VvNCED2 and VvZDS in 10 grape varieties of 3 different colors showed a gradually increasing trend,indicating that they had a weaker effect on the accumulation of carotenoids in grapes.In addition,the expression level of VvOR gene in grape fruits of three different colors varied during the ripening of grape fruit,but always had the lowest or highest expression level in the color-changing period,indicating that VvOR gene may play a certain role in the color-changing period to affect the synthesis of carotenoids.