The Correlation Analysis Between Expression Of SPS,SS Associated With Sucrose Metabolism And Sucrose Accumulation In Sweet Sorghum

Alcohol production by using sweet sorghum (Sorghum bicolor L. Moench) might be an alternative way to provide energy for the world. Using sweet sorghum and normal sorghum as material, the expression of sucrose phosphate synthetase (SPS),sucrose synthase(SS), key enzymes of sucrose metabolism in sorghum, were investigated by using Western blot. To better understand the mechanism of sucrose accumulation, the correlation of sucrose content and sucrose phosphate synthetase (SPS),sucrose synthase(SS) expression was analyzed by monitoring the expression of SPS in leaves (source) and stems (sink). (1) The results of SPS investigating indicated that the sucrose content, the expression of SPS in leaves and stems were increased along with the growth of sorghum, reached the highest level at grain filling stage, and decreased at dough stage. The correlation coefficient between sugar content in stems of sweet sorghum and SPS protein expression in leaves was 0.895, and the correlation coefficient was 0.781 as compared with SPS protein expression in stems. In comparison between sweet and normal sorghums, there was no visible difference of SPS expression in leaves, while the SPS expression level in stems of sweet sorghum is much higher than that in normal sorghum. (2) The results of SS investigating indicated that the SS protein expression in leaf at seedling stage was high comparatively, when at jointing and heading stage, SS expression was low in leaves and stems, along with sorghum development, since flowering stage, SS expression increased sharply, decreased at dough stage. The correlation coefficient between sugar content in stems of sweet sorghum and SS protein expression in leaves was 0.777, and the correlation coefficient was 0.903 as compared with SS protein expression in stems. In comparison between sweet and normal sorghums, the SS protein expression change trend was reversely in leaves. In stems, SS protein expression was universally low at jointing stage; at flowering stage, SS expression in sweet sorghum stems was obviously higher than normal sorghum. It showed that sucrose content in sweet sorghum is also correlative with SS protein expression in leaves and stems.