Abstract:

A pair of primers, designed from conserved regions of plant vacuolar invertase genes, was used to screen Citrus sinensis vacuolar invertase gene ( CSVI) from C.sinensis genomic library. The positive λ phage was isolated by filter paper absorption phage PCR, and cultured largely. DNA from the positive λ phage was digested with several restriction enzymes. The positive fragments judged by DIG southern blotting analysis, were reclaimed, modified, cloned into pUC19 and pUCm-T, and sequenced respectively. The result indicated that the sequence was 4 722 bp including 6 exons and 5 introns, coding 588 amino acids. It was found to have 68%, 68% and 62% homology respectively to Solanum tuberosum (X70368), Lycoperscion esculentam (Z12025) and Prunus cerasus (AY048579) vacuolar invertases by blast analysis in GenBank. Meanwhile, it was subclassed into plant vacuolar invertase by phylogenetic relation analysis. CSVI had been registered in GenBank (Accession No. AF433643). This work will contribute to a study on the molecular mechanisms of accumulation and catabolism of sucrose during Citrus fruit development, and improvement of Citrus fruit quality by gene engineering.

Key words: Citrus sinensis, Vacuolar invertase, Gene isolation