A flavin-dependent monooxygenase produces nitrogenous tomato aroma volatiles using cysteine as a nitrogen source.

Autor:	Liscombe DK; Biochemistry Group, Vineland Research and Innovation Centre, Vineland Station, ON LOR 2E0, Canada.; Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada., Kamiyoshihara Y; Horticultural Sciences, University of Florida, Gainesville, FL 32611., Ghironzi J; Département de Phytologie, Université Laval, Quebec City, QC G1V 0A6, Canada., Kempthorne CJ; Biochemistry Group, Vineland Research and Innovation Centre, Vineland Station, ON LOR 2E0, Canada.; Chemical Biotechnology Graduate Program, Brock University, St. Catharines, ON L2S 3A1, Canada., Hooton K; Biochemistry Group, Vineland Research and Innovation Centre, Vineland Station, ON LOR 2E0, Canada., Bulot B; Département de Phytologie, Université Laval, Quebec City, QC G1V 0A6, Canada., Kanellis V; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada., McNulty J; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada., Lam NB; Horticultural Sciences, University of Florida, Gainesville, FL 32611., Nadeau LF; Département de Phytologie, Université Laval, Quebec City, QC G1V 0A6, Canada., Pautler M; Genomics Services, Platform Genetics Inc., Vineland Station, ON L0R 2E0, Canada., Tieman DM; Horticultural Sciences, University of Florida, Gainesville, FL 32611., Klee HJ; Horticultural Sciences, University of Florida, Gainesville, FL 32611; charles.goulet@fsaa.ulaval.ca hjklee@ufl.edu., Goulet C; Département de Phytologie, Université Laval, Quebec City, QC G1V 0A6, Canada; charles.goulet@fsaa.ulaval.ca hjklee@ufl.edu.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2022 Feb 15; Vol. 119 (7).
DOI:	10.1073/pnas.2118676119
Abstrakt:	Tomato ( Solanum lycopersicum ) produces a wide range of volatile chemicals during fruit ripening, generating a distinct aroma and contributing to the overall flavor. Among these volatiles are several aromatic and aliphatic nitrogen-containing compounds for which the biosynthetic pathways are not known. While nitrogenous volatiles are abundant in tomato fruit, their content in fruits of the closely related species of the tomato clade is highly variable. For example, the green-fruited species Solanum pennellii are nearly devoid, while the red-fruited species S. lycopersicum and Solanum pimpinellifolium accumulate high amounts. Using an introgression population derived from S. pennellii , we identified a locus essential for the production of all the detectable nitrogenous volatiles in tomato fruit. Silencing of the underlying gene ( SlTNH1 ; Solyc12g013690 ) in transgenic plants abolished production of aliphatic and aromatic nitrogenous volatiles in ripe fruit, and metabolomic analysis of these fruit revealed the accumulation of 2-isobutyl-tetrahydrothiazolidine-4-carboxylic acid, a known conjugate of cysteine and 3-methylbutanal. Biosynthetic incorporation of stable isotope-labeled precursors into 2-isobutylthiazole and 2-phenylacetonitrile confirmed that cysteine provides the nitrogen atom for all nitrogenous volatiles in tomato fruit. Nicotiana benthamiana plants expressing SlTNH1 readily transformed synthetic 2-substituted tetrahydrothiazolidine-4-carboxylic acid substrates into a mixture of the corresponding 2-substituted oxime, nitro, and nitrile volatiles. Distinct from other known flavin-dependent monooxygenase enzymes in plants, this tetrahydrothiazolidine-4-carboxylic acid N -hydroxylase catalyzes sequential hydroxylations. Elucidation of this pathway is a major step forward in understanding and ultimately improving tomato flavor quality. Competing Interests: The authors declare no competing interest. (Copyright © 2022 the Author(s). Published by PNAS.)
Databáze:	MEDLINE
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