| Title: | PbABCG1 and PbABCG2 transporters are required for the emission of floral monoterpenes in Phalaenopsis bellina |
| Author(s): | Chang YL; Huang LM; Kuo XZ; Chen YY; Lin ST; Jeng MF; Yeh HH; Tsai WC; Chen HH; |
| Address: | "Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan. Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, 701, Taiwan. Orchid Research and Development Center, National Cheng Kung University, Tainan, 701, Taiwan. Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 115, Taiwan" |
| ISSN/ISBN: | 1365-313X (Electronic) 0960-7412 (Linking) |
| Abstract: | "Terrestrial plants emit volatiles into the atmosphere to attract both pollinators and the enemies of herbivores, for defense. Phalaenopsis bellina is a scented orchid species in which the main scent components are monoterpenes, including linalool and geraniol, and their derivatives. Here, we investigated whether ABC transporters are involved in floral scent emission. We carried out whole-genome identification of ABC transporter-related genes using four floral transcriptomics libraries of P. bellina. We identified 86 ABC subfamily G genes related to terpenoid transport. After comparing the gene expression patterns of P. bellina with that of Phalaenopsis aphrodite subsp. formosana, a scentless species, followed by gene-to-gene correlation analysis, PbABCG1 and PbABCG2 were selected. The temporal expression of both PbABCG1 and PbABCG2 was highly correlated with that of the key enzyme PbGDPS and the major transcription factor PbbHLH4 in monoterpene biosynthesis, with optimal expression on day 5 post-anthesis. Spatial gene expression analysis showed that PbABCG1 was highly expressed in sepals, whereas PbABCG2 was expressed in the lip. Subcellular localization with a GFP fusion protein revealed that both PbABCG1 and PbABCG2 are cytoplasmic membrane proteins. Co-downregulation of PbABCG1 and PbABCG2 using both double-strand RNA interference and tobacco rattle virus-based gene silencing led to a significant decrease in monoterpene emission, accompanied by an increase in the internal monoterpene pools. Furthermore, ectopic expression of PbABCG1 and PbABCG2 in an ABC16(-) mutant yeast strain rescued its tolerance to geraniol. Altogether, our results indicate that PbABCG1 and PbABCG2 play substantial roles in monoterpene transport/emission in P. bellina floral scent" |
| Keywords: | *Monoterpenes/metabolism Plant Proteins/genetics/metabolism Flowers/metabolism *Orchidaceae/genetics PbABCG Phalaenopsis floral scent geraniol linalool monoterpenes transporter; |
| Notes: | "MedlineChang, Ya-Lan Huang, Li-Min Kuo, Xuan-Zhou Chen, You-Yi Lin, Shao-Ting Jeng, Mei-Fen Yeh, Hsin-Hung Tsai, Wen-Chieh Chen, Hong-Hwa eng Research Support, Non-U.S. Gov't England 2023/02/05 Plant J. 2023 Apr; 114(2):279-292. doi: 10.1111/tpj.16133. Epub 2023 Feb 22" |
