Cloning Of PSY,LycB CDNA From Lycium Barbarum And Transformation Into Eustoma Grandiflorum

Carotenoids have a range of diverse biological functions. They are essential components of photosynthetic membranes in plants, function as copigments of photosynthesis and photoprotectant. They also function in pigmentation of flowers and fruits. Carotenoids play an important role in human health. Nearly one tenth of carotenoids are precursor of provitamin A. It was attracted to regulate carotenoid biosynthesis via genetic engineering, improve quality of vegetable and fruit, and alter flowers color.Lycium barbarum is a traditional Chinese medicine that is rich in carotenoids. Up to now, gene cloning of carotenoid biosynthesis enzymes in Lycium barbarum has not been reported. So applying Lycium barbarum as material, gene of carotenoid biosynthesis enzymes would be cloned in this paper.Eustoma grandiflorum is one of the pot flowers and cut flowers, which has much higher economic, viewing and admiring value. It is a more effective and quicker method than conventional breeding to alter flower colour using genetic engineering.This paper reported our results of cloning of Phytoene synthase (PSY) and lycopene β-cyclase(LycB) from cDNA library of Lycium barbarum, the construction of their plant expression vector and establishment of leaf regeneration system of Eustoma grandiflorum in vitro. PSY gene was transformed into Eustoma grandiflorum via Agrobacterium tumefaciens. The factors affecting genetic transformation were investigated. The main results were as follows.1. cDNA library of Lycium barbarum was constructed, whose recombination rate was 88.1% and the capacity of library was 2.78×10~5 pfu/ml.2. Phytoene synthase (PSY) gene and lycopene β-cyclase (LycB) gene were cloned from cDNA library of Lycium barbarum by PCR. They were further inserted into vector pGEM-T. The sequence analysis showed that PSY cDNA was 1 292 bp long with an open reading frame of 1 275 bp, and encoded a polypeptide of 425 animo acids. It s cDNA sequence showed 75%-80% identity, and the amino acid sequence shared 70%-80% identity with those of PSY from Lycopersicon esculentum, Capsicum annuum, Arabidopsis thaliana, Zea Mays, Cucumis melo respectively. GenBank accession number of PSY was AY920918LycB cDNA was composed of 1 541 bp with an open reading frame of 1 524 bp, which encodes a polypeptide of 508 animo acids. The cDNA sequence and the deduced amino acid sequence are significantly conserved when compared with those of LycB from...