Apricot Sucrose Transporters Gene PaSUC4 And Functional Verification

Apricot belongs to Rosaceae Prunoideae Armeniaca. Its fruit and nuts are edible. It is originated from China and the wild and cultivated variety resources are very rich. It occupies a very important position in people's lives and gardening industry in China. The accumulation of soluble sugar is the main quality index of apricot fruit, thus improvement of sugar content in apricot becomes very important. Sucrose is the main form of carbohydrate in fruit trees for long distance transportation. It is transported through the phloem and accumulated in the fruit to increase the sugar content in the fruit. It is also transported over long distances to other parts of the fruit trees, and provides the energy for the vegetative growth. And sucrose is mainly transported in apoplasmic way, in which the sucrose body is transported across the membrane including the process of phloem loading and unloading. This process needs the help of a carrier protein in the plasma membrane. The carrier protein is called sugar- proton transport protein, also called sucrose transporter, SUT.Reverse transcript PCR technology was employed in this study. Prunus armeniaca sucrose transport protein SUC4(PaSUC4) was obtained from Jinong red apricot. The full cDNA was2480 bp according to the sequencing result. The codon region was 1500 bp, encoding 499 amino acids,GenBank number is KT223003. The predicted protein molecular weight is 53.58 kDa, the isoelectric point is 9.31. The 3' untranslated region(3'UTR) is 945 bp.The expression level of PaSUC4 was the highest in mature leaves and lowest in pistils. The characteristics of predicted protein have been analyzed by bioinformatics software.For further verification of the gene biological function, the expression vector had been constructed and transformed into tobacco plants. Four transgenic plants were obtained according to PCR detection and applied important materials for biological functional analysis.Total apricot RNAs were extracted from different parts of different periods, the fluorescence quantitative PCR analysis were performed. The results showed that PaSUC4 was expressed in immature fruits, young leaves, mature leaves, petals and young shoots, and less expressed in pistil. The expression pattern showed tissue-specific. In mature leaves source was expressed in the highest quantity, and in petals, new shoots, young fruit, new leaves the expression level was in turn reduced express. The minimum expression was detected in pistil. It is speculated that PaSUC4 may has a dual function.