CYP79D73 Participates in Biosynthesis of Floral Scent Compound 2-Phenylethanol in Plumeria rubra. Issue 1 (25th February 2019)

• Record Type: Journal Article
• Authors: Dhandapani, Savitha; Jin, Jingjing; Sridhar, Vishweshwaran; Chua, Nam-Hai; Jang, In-Cheol
• Is Part Of: Plant physiology. Volume 180:Issue 1(2019)
• Page Start: 171
• Page End: 184
• Publication Date: 2019-02-25
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.19.00098
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : A cytochrome P450 enzyme contributes to the production of 2-phenylethanol and nitrogen-containing volatiles in Plumeria. Abstract: Plumeria ( Plumeria rubra ), well known for its brightly colored and fragrant flowers, emits a number of floral volatile organic compounds (VOCs). Plumeria flowers emit a total of 43 VOCs including nine phenylpropanoids/benzenoids, such as 2-phenylethanol (2PE), benzaldehyde, 2-phenylacetaldehyde (PAld), ( E/Z ) - phenylacetaldoxime (PAOx), benzyl nitrile (BN), and 2-phenylnitroethane (PN). To identify genes and pathways involved in the production of the major compound 2PE, we analyzed the plumeria floral transcriptome and found a highly expressed, flower-specific gene encoding a cytochrome P450 family 79D protein (PrCYP79D73), which catalyzed the formation of ( E/Z )-PAOx. Feeding experiments with deuterated phenylalanine or deuterated ( E/Z )-PAOx showed that ( E/Z )-PAOx is an intermediate in the biosynthesis of 2PE, as are two nitrogen-containing volatiles, BN and PN, in plumeria flowers. Crude enzyme extracts from plumeria flowers converted l -phenylalanine to ( E/Z )-PAOx, PAld, 2PE, BN, and PN. The biosynthesis of these compounds increased with addition of PrCYP79D73-enriched microsomes but was blocked by pretreatment with 4-phenylimidazole, an inhibitor of cytochrome P450 enzymes. Moreover, overexpression of PrCYP79D73 in Nicotiana benthamiana resulted in the emission of ( E/Z )-PAOx as well as PAld, 2PE, BN, and PN, all of which were also found among plumeria floral VOCs. Taken together, our results demonstrate that PrCYP79D73 is a crucial player in the biosynthesis of the major floral VOC 2PE and other nitrogen-containing volatiles. These volatiles may be required for plant defense as well as to attract pollinators for the successful reproduction of plumeria.