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Molecules

Title:		Composition and Biosynthesis of Scent Compounds from Sterile Flowers of an Ornamental Plant Clematis florida cv. 'Kaiser'
Author(s):		Jiang Y; Qian R; Zhang W; Wei G; Ma X; Zheng J; Kollner TG; Chen F;
Address:		"College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China. Zhejiang Institute of Subtropical Crops, 334 Xueshan Road, Wenzhou 325005, China. Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA. Department of Biochemistry, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany"
Journal Title:		Molecules
Year:		2020
Volume:		20200408
Issue:		7
Page Number:		-
DOI:		10.3390/molecules25071711
ISSN/ISBN:		1420-3049 (Electronic) 1420-3049 (Linking)
Abstract:		"Clematis florida is a popular ornamental vine species known for diverse colors and shapes of its flowers but not for scent. Here we investigated the composition and biosynthesis of floral scent in 'Kaiser', a fragrant cultivar of C. florida that has sterile flowers. Volatile profiling revealed that flowers of 'Kaiser' emit more than 20 compounds, with monoterpenes being most abundant. Among the three floral organs, namely sepals, transformed-petals, and ovaries, ovaries had the highest rates of total volatile emission. To determine the molecular mechanism underlying floral scent biosynthesis in 'Kaiser', we sequenced a flower transcriptome and searched the transcriptome for terpene synthase genes (TPSs), which are key genes for terpene biosynthesis. Among the TPS genes identified, three were putative intact full-length genes and were designated CfTPS1, CfTPS2, and CfTPS3. Phylogenetic analysis placed CfTPS1, CfTPS2, and CfTPS3 to the TPS-g, TPS-b, and TPS-a subfamily, respectively. Through in vitro enzyme assays with Escherichia coli-expressed recombinant proteins, both CfTPS1 and CfTPS2 were demonstrated to catalyze the conversion of geranyl diphosphate to linalool, the most abundant constituent of C. florida floral scent. In addition, CfTPS1 and CfTPS2 produced the sesquiterpene nerolidol from (E,E)-farnesyl diphosphate. CfTPS3 showed sesquiterpene synthase activity and produced multiple products in vitro. All three CfTPS genes showed higher levels of expression in sepals than those in transformed-petals and ovaries. Our results show that despite being sterile, the flowers of 'Kaiser' have normal mechanisms for floral scent biosynthesis that make the flowers fragrant"
Keywords:		"Amino Acid Sequence Biocatalysis *Biosynthetic Pathways Clematis/*chemistry/genetics Flowers/*chemistry Gene Expression Regulation, Plant Genes, Plant Molecular Sequence Annotation Odorants/*analysis Phylogeny *Plant Infertility Plant Proteins/chemistry/g;"
Notes:		"MedlineJiang, Yifan Qian, Renjuan Zhang, Wanbo Wei, Guo Ma, Xiaohua Zheng, Jian Kollner, Tobias G Chen, Feng eng 2016C02056-13-4/Zhejiang province Major science and technology project for new variety breeding of agriculture (forest) in the13th Five-Year Plan-Collection, conservation, evaluation and utilization of clematis vine flower resources/ ZX201901/Open Research Subject of Key Laboratory of Plant Germplasm Enhancement of Specialty Forestry of Central and South of Zhejiang Province/ Z20170001/Wenzhou City Seed Seedling Project Study on Germplasm Innovation and Breeding of New Variety of Grandiflora Clematis/ Switzerland 2020/04/12 Molecules. 2020 Apr 8; 25(7):1711. doi: 10.3390/molecules25071711"