Transcriptomic analysis of floral organs from Phalaenopsis orchid by using oligonucleotide microarray

Area of Science:

• Plant developmental biology
• Molecular evolution
• Orchid genomics

Background:

• Orchids exhibit remarkable floral diversity, particularly in labellum morphology, indicating evolutionary success.
• The intricate development of orchid perianths offers a valuable model for developmental biology studies.
• Research into the molecular mechanisms of orchid floral development remains limited.

Purpose of the Study:

• To develop a functional genomic tool for orchid research.
• To compare transcriptomes across different floral organs (sepal, petal, labellum) in Phalaenopsis orchids.
• To identify differentially expressed genes and transcription factors associated with specific floral organ functions.

Main Methods:

• Development of an oligomicroarray with 14,732 unigenes from Phalaenopsis expressed sequence tags.
• Transcriptome comparison of sepal, petal, and labellum using the developed microarray.
• Annotation of differentially expressed unigenes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.

Main Results:

• Identification of 173, 11, and 285 highly differentially expressed unigenes in sepal, petal, and labellum, respectively.
• Significant differences in unigenes related to energy, lipid, and terpenoid metabolism between labellum and tepals.
• Discovery of labellum-dominant MADS-box and sepal-dominant WRKY transcription factors.

Conclusions:

• The developed microarray serves as a crucial functional genomic tool for orchid research.
• Data suggest the potential to identify genes specific to sepal, petal, and labellum functions.
• This study bridges the gap in genomic resources for orchids compared to model organisms.