Genetic dissection of vitamin E biosynthesis in tomato

ALMEIDA J, QUADRANA L, ASIS R, SETTA N, DE GODOY F, BERMÚDEZ L, OTAIZA SN, CORRÊA DA SILVA JV, FERNIE AR, CARRARI F AND ROSSI M

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Año: 2010

0022-0957

  Genetic dissection of vitamin E biosynthesis in tomato Genetic dissection of vitamin E biosynthesis in tomato ABSTRACT Vegetables are critical for human health as they are a source of multiple vitamins including vitamin E (VTE). In plants, the synthesis of VTE compounds, tocopherol and tocotrienol, derives from precursors of the shikimate and methylerythritol phosphate pathways. Quantitative trait loci (QTL) for £-tocopherol content in ripe fruit have previously been determined in an S. pennellii tomato introgression line population. In this work, we studied variations of tocopherol isoforms (£, ƒÒ, ƒ× and ƒÔ) in ripe fruits of these lines. In parallel we identified and mapped all tomato genes structurally associated with VTE biosynthesis. Previously identified VTE QTL on chromosomes 6 and 9 were confirmed whilst novel ones were identified in chromosome 7 and 8. Integrated analysis at the metabolic, genetic and genomic levels allowed us to propose sixteen candidate loci putatively affecting tocopherol content in tomato. A comparative analysis revealed polymorphisms at nucleotide and amino acid levels between S. lycopersicum and S. pennellii candidate alleles. Moreover, evolutionary analyses showed the presence of codons evolving under both neutral and positive selection which may explain the phenotypic differences between species. These data represent an important step for understanding the genetic determinants of VTE natural variation in tomato fruit and as such in our ability to improve the content of this important nutriceutical.