Construction of Flower-specific Chimeric Promoters and Analysis of Their Activities in Transgenic Torenia.

Flower-specific promoters can enable transgenic enhancement of valuable ornamental traits, including flower shape and color. However, the identification of strong, tissue-specific promoters remains a limiting factor. To obtain enhanced flower-specific promoters, we constructed four chimeric promoters (p35S- PCHS-Ω, p35S- LCHS-Ω, pOCS- PCHS-Ω and pOCS- LCHS-Ω) combining the 35S or OCS enhancer fused to a 302 bp CHSA core promoter fragment from petunia ( PCHS) or a 307 bp CHS core promoter fragment from lily ( LCHS), and also containing an omega element (Ω). Each promoter was fused to the β-glucuronidase ( GUS) reporter gene, and we examined the levels and tissue specificity of GUS expression in transgenic Torenia fournieri. p35S- PCHS-Ω and p35S- LCHS-Ω drove strong, constitutive GUS expression in all tissues, especially in colored corollas (p35S- PCHS-Ω) or in colored corollas and roots (p35S- LCHS-Ω). pOCS- PCHS-Ω drove stronger GUS expression in colored corollas than in other tissues but expression was weaker than that of p35S- PCHS-Ω. pOCS- LCHS-Ω drove GUS in colored corollas but also in roots. Among the four chimeric promoters, pOCS- PCHS-Ω exhibited stronger activity only in colored corollas, making it useful for transgenic enhancement of floral traits, such as expressing 'blue genes' in lily to produce new lines with blue flowers. [ABSTRACT FROM AUTHOR]