Separation and Expression Analysis of the Betalain Synthase 4,5-DOPA-dioxygenase Gene in Bougainvillea
In the study,three cDNA encoding the dihydroxyphenylalanine( DOPA) dioxygenase were identified from three species of bougainvillea(B. spectabilis ‘Splendens',B. buttiana ‘Mahara',B. pruviana ‘Thimma'). The cDNA was 902 bp(B. spectabilis ‘Splendens'),899 bp(B. buttiana ‘Mahara') and 899 bp(B. pruviana ‘Thimma'),similar to the known cDNA of Bougainvillea,respectively. The deduced molecular weight was 33.8 ku( B.spectabilis ‘ Splendens'),33.1 ku( B. buttiana ‘ Mahara') and 33.2 ku( B. pruviana ‘ Thimma'). pI of the three deduced proteins was 5.62,5.54 and 5.94,respectively. The expression of the enzyme was explored from four species of Bougainvillea( B. spectabilis ‘ Splendens',B. buttiana ‘ Mahara',B. glabra ‘ Alba',B. pruviana‘Thimma'). The results showed that the gene of 4,5-DOPA-dioxygenase was expressed variably obviously among the flowers of four species. Generally,the expression of the gene was weak in early stage of blooming,was strong in blooming and weak in late stage. The gene was expressed most strongly in scarlet B. buttiana ‘Mahara'while expressed most weakly in white B. glabra ‘ Alba'. Information above indicated that expression strength of4,5-DOPA-dioxygenase gene in Bougainvilleas is closely related to the color depth.