The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps
Author
Saladié, Montserrat
Wright, Louwrance P.
Rodriguez-Concepcion, Manuel
Phillips, Michael A.
Publication date
2014-07-10ISSN
0022-0957
Abstract
The 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway provides the precursors for the biosynthesis of plastidial isoprenoids, which include the carotenoid pigments of many fruits. We have analysed the genes encoding the seven enzymes of the MEP pathway in melon (Cucumis melo L.) and determined that the first one, 1-deoxyxylulose 5-phosphate synthase (DXS), and the last one, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR), are represented in the genome as a small gene family and paralogous pair, respectively. In the case of DXS, three genes encode functional DXS activities which fall into previously established type I (CmDXS1) and II (CmDXS2a and CmDXS2b) categories, while a fourth
DXS-like gene belonging to the type III group did not encode a protein with DXS activity. Their expression patterns and phylogenies suggest that CmDXS1 is functionally specialized for developmental and photosynthetic processes, while CmDXS2a and CmDXS2b are induced in flowers and ripening fruit of orange- (but not white-) fleshed varieties, coinciding with β-carotene accumulation. This is the first instance connecting type II DXS genes to specialized isoprenoid biosynthesis in the fruit of an agronomically important species. Two HDR paralogues were shown to encode functional enzymes,
although only CmHDR1 was highly expressed in the tissues and developmental stages tested. Phylogenetic analysis showed that in cucurbits such as melon, these HDR paralogues probably arose through individual gene duplications in a common angiosperm ancestor, mimicking a prior division in gymnosperms, while other flowering plants, including apple, soy, canola, and poplar, acquired HDR duplicates recently as homoeologues through large-scale genome duplications. We report the influence of gene duplication history on the regulation of the MEP pathway in melon and the role of specialized MEP-pathway isoforms in providing precursors for β-carotene production in orange-fleshed melon varieties.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
575 - General genetics. General cytogenetics
Pages
16
Publisher
Oxford University Press
Is part of
Journal of Experimental Botany
Citation
Saladié, Montserrat, Louwrance P. Wright, Jordi Garcia-Mas, Manuel Rodriguez-Concepcion, and Michael A. Phillips. 2014. "The 2-C-Methylerythritol 4-Phosphate Pathway In Melon Is Regulated By Specialized Isoforms For The First And Last Steps". Journal Of Experimental Botany 65 (17): 5077-5092. doi:10.1093/jxb/eru275.
Grant agreement number
MICINN/Programa Nacional de Proyectos de Investigación Fundamental/BIO2011-23680/ES/MODULACION AMBIENTAL DE LA BIOSINTESIS DE CAROTENOIDES EN PLANTAS/
MICINN/Programa Nacional de Proyectos de Investigación Fundamental/PIM2010IPO-00660/ES/REVERSED ISOPRENOID BIOSYNTHESIS USING ISOPRENE AS ABUNDANT SUBSTRATE/
MEC/Programa nacional de medios de transporte/CSD2007-00036/ES/Centro de Genómica Básica y de orientación Agroalimentaria/
MEC/Programa Nacional de Biodiversidad, Ciencias de la Tierra y Cambio Global/GEN2006-27773-C2-1-E/ES/UNDERSTANDING THE CLIMACTERIC VS NON-CLIMACTERIC FRUIT RIPENING MECHANISMS IN MELON USING TRANSCRIPTOMIC, METABOLOMIC AND REVERSE GENETIC APPROACHES/MELRIP
Program
Genòmica i Biotecnologia
This item appears in the following Collection(s)
- ARTICLES CIENTÍFICS [2850]
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by/4.0/