Abstract:

Lycopene β-cyclase, which catalyzes linear lycopene to cycle and become β-carotene, is one of key enzymes in the β-carotene biosynthesis pathway. Total RNA was purified from sweetpotato tuberous roots and was reverse-transcripted into cDNA, and the consensus sequence of the gene for lycopene β-cyclase (lyc-b) was amplified from the cDNA, then total cDNA sequence of lyc-b was obtained by the ways of Rapid Amplification of cDNA End (RACE). Sequence analysis showed that the complete sequence of lyc-b consists of 1 844 bp, which has an Open Reading Frame of 1 503 bp and encodes a protein of 501 amino acids. The gene was constructed into plant express vector p23-lyc-b，and was transferred into tobacco by Agrobacterium-mediated method. The results of PCR and Southern blot showed that the gene was integrated into tobacco genome.

Key words: Sweetpotato (Ipomoea batatas L.), Lycopeneβ-cyclase, Gene clone, Vector construction, Transformation