Study On The Relationship Between Sucrose Synthase Gene Expression And Sugar Accumulation In Different Sweet Sorghum

Sweet sorghum is a new generation of energy crops,It is the most important raw material for the production of fuel ethanol,cultivating high sugar content new sweet sorghum variety is the energy fuel ethanol industrialization important foundation.Sweet sorghum variety breeding not only requires high yield,but also requires high sugar content,good resistance to disease resistance of new sweet sorghum varieties.Because of different purposes,the sugar content and composition of the requirements of a certain difference,but the overall requirements of breeding yield and sugar content of high quality varieties.In this experiment,ten varieties of sweet sorghum were selected to compare the sugar content and the activity of SS and SPS in different varieties of sweet sorghum at different stages.The differences of SS gene expression among 10 varieties of sweet sorghum were investigated by real-time PCR at different stages,to understand the law of sugar accumulation in sweet sorghum.The results were reported as the follow:1.The change of sucrose content and total sugar content in different growth periods was consistent,it is a rising trend,reached its maximum at maturity.The trend of fructose and glucose content is different from that of total sugar,the change of fructose content was increased first,then decreased and increased again,the glucose content was increased and then decreased.In leaves,there was a significant positive correlation between sucrose content and total sugar content(R=0.632,P<0.01),no correlation between fructose content and total sugar content(R=0.227,P=0.159),a negative correlation between total sugar content and glucose content(R=-0.328,P<0.05).2.The trends of SS activity and SPS activity in leaves is the same,it is a rising trend,reached its maximum at maturity.The activity of SS was higher than that of SPS.In the early growth stage,the difference of SS and SPS activities in leaves is small,but in the stage of sugar accumulation,the SS enzyme activity is generally higher than that of the SPS enzyme activity.In the leaves,there was a positive correlation between sucrose SS and SPS activity(R=0.860,P<0.05,R=0.876,P<0.05),it is illustrated that SPS and SS is the effect enzymes of sweet sorghum sucrose metabolism.In the mature stage,SS activity and SPS activity of LTR108 were the highest.3.Through the quantitative analysis of relative expression of SS gene in 10 varieties ofsweet sorghum at different stages,the highest expression level of SS gene was LTR108 at all stages.The trends in expression of SS gene was consistent with the sucrose content.The different sugar content in different varieties of sweet sorghum and the accumulation of sucrose content were regulated by SS gene.