title: Molecular analysis of proanthocyanidins related to pigmentation in brown cotton fibre (Gossypium hirsutum L.).
abstract: The structural characteristics and component differences of proanthocyanidins in brown and white cotton fibres were identified by nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analyses. Proanthocyanidins in brown and white cotton fibres were found to contain mainly procyanidin (PC) and prodelphidin (PD) units with 2, 3-cis form (epigallocatechin and epicatechin). However, part of the proanthocyanidins in the white cotton fibres were modified by acylation and were constitutively different from the proanthocyanidins in brown cotton fibres. The relative amount of PD was similar to that of PC in white cotton fibres, while proanthocyanidins in brown cotton fibres consisted mainly of PD units with a relative ratio of 9:1. In brown cotton fibres, the proanthocyanidin monomeric composition was consistent with the expression profiles of proanthocyanidin synthase genes, suggesting that anthocyanidin reductase represented the major flow of the proanthocyanidin biosynthesis pathway. In addition, the structural characteristics and component differences of proanthocanidins in brown and white cotton fibres suggested that quinones, the oxidation products of proanthocyanidins, were the direct contributors to colour development in brown cotton fibre. This was demonstrated by vanillin-HCl staining and Borntrager's test. Collectively, these data demonstrated that the biosynthesis of proanthocyanidins is a crucial pigmentation process in brown cotton fibre, and that quinones may represent the main pigments contributing to formation of the the brown colour. This study revealed the molecular basis of pigmentation in brown cotton fibres, and provided important insights for genetic manipulation of pigment production in cotton fibres.
authors.affiliation: College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi 832000, Xinjiang Province, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Feng
authors.affiliation: College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi 832000, Xinjiang Province, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Centre for Legumes in Mediterranean Agriculture, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Shaofang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Chemical Industry of Forest Products of Chinese Academy of Forestry, Nanjing 210042, Jiangsu Province, China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi 832000, Xinjiang Province, China.
authors.forename: Yongchuang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi 832000, Xinjiang Province, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Xue
authors.affiliation: College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 310036, Zhejiang Province, China.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Chemical Industry of Forest Products of Chinese Academy of Forestry, Nanjing 210042, Jiangsu Province, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Agriculture/The Key Laboratory of Oasis Eco-agriculture, Shihezi University, Shihezi 832000, Xinjiang Province, China sunjie@shzu.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D053898:Biosynthetic Pathways; D032561:Cotton Fiber; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D010088:Oxidoreductases / Q000378:metabolism; D010858:Pigmentation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D044945:Proanthocyanidins / Q000737:chemistry / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D044945:Proanthocyanidins; C013221:proanthocyanidin; D010088:Oxidoreductases
keywords: Anthocyanidin reductase (ANR); brown cotton; nuclear magnetic resonance (NMR); pigment; proanthocyanidin; quinone.