Date Published: September 5, 2018
Publisher: Public Library of Science
Author(s): Ronghui Fan, Yiquan Chen, Xiuxian Ye, Jianshe Wu, Bing Lin, Huaiqin Zhong, Serena Aceto.
Polianthes tuberosa is a popular ornamental plant. Its floral scent volatiles mainly consist of terpenes and benzenoids that emit a charming fragrance. However, our understanding of the molecular mechanism responsible for the floral scent of P. tuberosa is limited. Using transcriptome sequencing and de novo assembly, a total of 228,706,703 high-quality reads were obtained, which resulted in the identification of 96,906 unigenes (SRA Accession Number SRP126470, TSA Acc. No. GGEA00000000). Approximately 41.85% of the unigenes were functionally annotated using public databases. A total of 4,694 differentially expressed genes (DEGs)were discovered during flowering. Gas chromatography-mass spectrometry analysis revealed that the majority of the volatiles comprised benzenoids and small amounts of terpenes. Homology analysis identified 13 and 17 candidate genes associated with terpene and benzenoid biosynthesis, respectively. Among these, PtTPS1, PtDAHPSs, PtPAL1, and PtBCMT2 might play important roles in regulating the formation of floral volatiles. The data generated by transcriptome sequencing provide a critical resource for exploring concrete characteristics as well as for supporting functional genomics studies. The results of the present study also lay the foundation for the elucidation of the molecular mechanism underlying the regulation of floral scents in monocots.
Floral scent is a crucial characteristic of ornamental plants, attracting pollinators for sexual reproduction and acting as a defense mechanism against pathogens, parasites, and herbivores [1–2]. Floral volatiles are mainly emitted by floral organs at specific flowering periods . Approximately 1,700 floral volatiles from 100 plant species have been identified to date . Floral volatiles consist of terpenoids, phenylpropanoids/benzenoids, and fattyacid derivatives, which are synthesized via different plant pathways .
P. tuberosa is a popular flower with a distinct floral scent. However, our understanding of the molecular mechanisms responsible for its floral scent is limited because genomic information on this species is currently unavailable. The present study utilized extensive cDNA sequence data to identify genes that control floral scent compounds and to further analyze floral scent biosynthesis in P. tuberosa. Here, eight cDNA libraries during flowering of P. tuberosa were obtained through transcriptome sequencing. A total of 96,906 unigenes was obtained. Approximately 41.85% of the assembled unigene sequences were annotated by public databases. The availability of data for P. tuberosa provides an important resource for exploring the characteristics of this species as well as for mining key genes and their functions in floral scent development.