Changes Of The Lycopene Content And Expression Analysis Of Key Genes In Tomato Fruits Of Different Developing Stages

This study used organic solvent extraction to optimize the extraction process of lycopene and optimized the parameters of high performance liquid chromatography for detecting the lycopene content,fresh tomato fruits as experimental materials.On this basis,the lycopene content differences were analyzed with different varieties,different periods,and different parts of fruit.Finally,the expression patterns of two key genes in the lycopene metabolism process were analyzed,through the fluorescent quantitative PCR technology.（1）Single factor and orthogonal experiments showed that pretreatment such as adding enzyme and stirring were beneficial to the extraction of lycopene,extraction temperature,extraction time had bigger influences on the lycopene extraction yield.The optimal extraction technology for ethyl acetate as extraction solvent,solid-liquid ratio 1:1,temperature 50℃,extracting time 5 h,extraction times 2.The Condition parameters of high performance liquid chromatography method for the determination of lycopene content was Symmetry^?C₁₈ column（150 x 4.6 mm,5μm）,methanol and acetonitrile（7:3）as mobile phase,the flow rate of 1.2 mL/min,detection wavelength of 472 nm,sample quantity 20μL,column temperature 35℃.（2）Among different tomatoes varieties,the lycopene content difference was significant.On the whole,the lycopene content of red tomatoes were obviously higher than that of pink tomatoes.Through the analysis of the difference among varieties,eight high lycopene tomato varieties were screened.The experimental results showed that lycopene content gradually increased with the improvement of fruit maturity,whether the red varieties or the pink varieties.The content was the lowest in green ripe stage and reached the peak in full ripeness period.The content in peel was higher than in pulp and placenta and roughly2.0 to 2.5 times of pulp and placenta.（3）In the process of tomato fruit ripening,the expression pattern of lycopene metabolism two key genes PDS and LCY-E was different.PDS gene expression quantity was lower originally and then gradually increased,which reached to maximum in maturity and almost 100 times the amount of green ripe stage expression.LCY-E gene expression sharply increased from green ripe stage to turning stage and reached to maximum in turning stage.However,from turning stage to mature period,LCY-E gene expression quantity significantly reduced.The experimental results showed that the PDS gene largely expression promoted the lycopene synthesis,and the significantly decreasing of LCY-E gene expression inhibited the lycopene degradation in fruit mature period.The common effect of two key genes PDS gene and LCY-E was conducive to the lycopene accumulation in mature period fruits.This study optimized lycopene extraction technology and the lycopene determination method in high performance liquid chromatography,and provided the technical support for further screening of tomato germplasm with high lycopene.The high lycopene resource materials laid a solid foundation to further develop tomato new varieties with high lycopene.To understand expression pattern of PDS and LCY-E provided a theoretical basis for the further study of lycopene metabolism regulation mechanism.