Abstract
Previously we developed genomic resources for orchids, including transcriptomic analyses using next-generation sequencing techniques and construction of a web-based orchid genomic database. Here, we report a modified molecular model of flower development in the Orchidaceae based on functional analysis of gene expression profiles in Phalaenopsis aphrodite (a moth orchid) that revealed novel roles for the transcription factors involved in floral organ pattern formation. Phalaenopsis orchid floral organ-specific genes were identified by microarray analysis. Several critical transcription factors including AP3, PI, AP1 and AGL6, displayed distinct spatial distribution patterns. Phylogenetic analysis of orchid MADS box genes was conducted to infer the evolutionary relationship among floral organ-specific genes. The results suggest that gene duplication MADS box genes in orchid may have resulted in their gaining novel functions during evolution. Based on these analyses, a modified model of orchid flowering was proposed. Comparison of the expression profiles of flowers of a peloric mutant and wild-type Phalaenopsis orchid further identified genes associated with lip morphology and peloric effects. Large scale investigation of gene expression profiles revealed that homeotic genes from the ABCDE model of flower development classes A and B in the Phalaenopsis orchid have novel functions due to evolutionary diversification, and display differential expression patterns.
Highlights
Sexual propagation is an important physiological event for both animals and plants
Four cultivars of Phalaenopsis normal and perolic mutant flowers were used in comparative pattern analysis, including Phalaenopsis equestris purchased from OX Orchids Farm (Tainan, Taiwan); P
Organ-specific genes were identified by the Specificity Measure (SPM) statistical method [36] after array data were normalized
Summary
Sexual propagation is an important physiological event for both animals and plants. In order to adapt to a dry environment, angiosperms have evolved many specialized flowering processes to achieve reproduction. Substantial work with model organisms ranging from morphological observation to study of molecular regulation has resulted in the elucidation of the reproductive development of flowering plants [1,2,3]. Great diversity in reproductive behavior is observed in various plant taxa suggesting that alternative strategies have been adopted during the courses of evolution. Orchids are of particular interest to biologists because of their unique and intriguing biological traits. The Orchidaceae, one of the largest families of Angiosperms, displays a high degree of speciation [4] with wide variations in floral characteristics, including morphology, color, size and fragrance that ensure successful pollination
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
