Abstract
Orchids are one of the most significant plants that have ecologically adapted to every habitat on earth. Orchids show a high level of variation in their floral morphologies, which makes them popular as ornamental plants in the global market. Floral scent and color are key traits for many floricultural crops. Volatile organic compounds (VOCs) play vital roles in pollinator attraction, defense, and interaction with the environment. Recent progress in omics technology has led to the isolation of genes encoding candidate enzymes responsible for the biosynthesis and regulatory circuits of plant VOCs. Uncovering the biosynthetic pathways and regulatory mechanisms underlying the production of floral scents is necessary not only for a better understanding of the function of relevant genes but also for the generation of new cultivars with desirable traits through molecular breeding approaches. However, little is known about the pathways responsible for floral scents in orchids because of their long life cycle as well as the complex and large genome; only partial terpenoid pathways have been reported in orchids. Here, we review the biosynthesis and regulation of floral volatile compounds in orchids. In particular, we focused on the genes responsible for volatile compounds in various tissues and developmental stages in Cymbidium orchids. We also described the emission of orchid floral volatiles and their function in pollination ecology. Taken together, this review will provide a broad scope for the study of orchid floral scents.
Highlights
The Orchidaceae family is one of the largest and widely diverse families of flowering plants, with more than 28,000 accepted species spanning 763 genera [1]
We give an overview of orchid floral volatiles with a focus on Cymbidium orchids; we review their importance in pollination ecology, genes encoding enzymes and transcription factors (TFs) responsible for the biosynthesis, and the regulation of orchid floral volatiles
Biosynthesis of Volatile organic compounds (VOCs) depends on the availability of carbon, nitrogen, and sulfur together with energy provided from the primary metabolism
Summary
The Orchidaceae family is one of the largest and widely diverse families of flowering plants, with more than 28,000 accepted species spanning 763 genera [1]. As fascinating and highly popular plants, orchids are valued because of their exquisite flowers and long floral lifespan. These plants consist of great diversity in floral form, size, color, fragrance, and texture. Orchids currently account for a prominent share of the world’s flower trade, with annual sales of more than $4 billion (USD) It is widely used in perfumes, cosmetics, florivores, and medicinal applications. Orchidaceae, with genome sizes in a 168-fold range (1C = 0.33–55.4 pg), are perhaps the most diverse angiosperm families [25]. We hope that our information will provide guidance for future studies on orchid floral scents
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
