Reduced transcription of a LEAFY-like gene in Alstroemeria sp. cultivar Green Coral that cannot develop floral meristems

Abstract

Alstroemeria sp. cv. Green Coral has numerous bracts instead of flowers, and its cyme structures are repeated eternally. Observations of the development and morphology of inflorescence in cv. Green Coral revealed that transition from inflorescence to floral meristem was restricted. We isolated and characterized floral meristem identity genes LEAFY-like (AlsLFY) and SQUAMOSA-like (AlsSQa and AlsSQb) genes from Alstroemeria ligtu. In situ hybridization results indicated that AlsSQa and AlsSQb were expressed in the dome-shaped floral meristems and all floral organ primordia in A. ligtu. Transcripts of AlsLFY accumulated early in the dome-shaped floral meristems; the signals were restricted later to the outer region of the floral meristem. These results indicate that AlsLFY, AlsSQa, and AlsSQb function as floral meristem identity genes. Expression profiles of AlsLFY, AlsSQa, AlsSQb, and other MADS-box genes were compared between A. ligtu and cv. Green Coral. AlsLFY, AlsDEFa, and AlsAGL6 transcripts were not detected at the shoot apices of cv. Green Coral but were detected in A. ligtu. The early induction and accumulation of AlsLFY transcripts in the inflorescence meristem of A. ligtu prior to development of the floral meristem suggest that downregulation of AlsLFY is likely to restrict the inflorescence-to-floral meristem transition in cv. Green Coral.