title: Suppression of 9-cis-epoxycarotenoid dioxygenase, which encodes a key enzyme in abscisic acid biosynthesis, alters fruit texture in transgenic tomato.
abstract: Cell wall catabolism during fruit ripening is under complex control and is key for fruit quality and shelf life. To examine the role of abscisic acid (ABA) in tomato (Solanum lycopersicum) fruit ripening, we suppressed SlNCED1, which encodes 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in the biosynthesis of ABA. To suppress SlNCED1 specifically in tomato fruits, and thus avoid the pleiotropic phenotypes associated with ABA deficiency, we used an RNA interference construct driven by the fruit-specific E8 promoter. ABA accumulation and SlNCED1 transcript levels in the transgenic fruit were down-regulated to between 20% and 50% of the levels measured in the control fruit. This significant reduction in NCED activity led to a down-regulation in the transcription of genes encoding major cell wall catabolic enzymes, specifically polygalacturonase (SlPG), pectin methyl esterase (SlPME), β-galactosidase precursor mRNA (SlTBG), xyloglucan endotransglycosylase (SlXET), endo-1,4-β-cellulose (SlCels), and expansin (SlExp). This resulted in an increased accumulation of pectin during ripening. In turn, this led to a significant extension of the shelf life to 15 to 29 d compared with a shelf life of only 7 d for the control fruit and an enhancement of fruit firmness at the mature stage by 30% to 45%. In conclusion, ABA affects cell wall catabolism during tomato fruit ripening via down-regulation of the expression of major catabolic genes (SlPG, SlPME, SlTBG, SlXET, SlCels, and SlExp).
authors: College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, China.
authors: Liang
authors: L
authors: Sun
authors: Yufei
authors: Y
authors: Sun
authors: Mei
authors: M
authors: Zhang
authors: Ling
authors: L
authors: Wang
authors: Jie
authors: J
authors: Ren
authors: Mengmeng
authors: M
authors: Cui
authors: Yanping
authors: Y
authors: Wang
authors: Kai
authors: K
authors: Ji
authors: Ping
authors: P
authors: Li
authors: Qian
authors: Q
authors: Li
authors: Pei
authors: P
authors: Chen
authors: Shengjie
authors: S
authors: Dai
authors: Chaorui
authors: C
authors: Duan
authors: Yan
authors: Y
authors: Wu
authors: Ping
authors: P
authors: Leng
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D003521:Cyclopropanes / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D049308:Dioxygenases / Q000235:genetics* / Q000378:metabolism*; D005638:Fruit / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010368:Pectins / Q000378:metabolism; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D011096:Polygalacturonase / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D034622:RNA Interference
chemical_list: D003521:Cyclopropanes; D009943:Organophosphorus Compounds; D010937:Plant Growth Regulators; D010940:Plant Proteins; C105498:1-methylcyclopropane; D000040:Abscisic Acid; D010368:Pectins; D003577:Cytochrome P-450 Enzyme System; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; C107203:abscisic acid 8'-hydroxylase; D016695:Glycosyltransferases; C473049:xyloglucan - xyloglucosyltransferase; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase; D011096:Polygalacturonase; C005073:ethephon