title: Melatonin promotes ripening and improves quality of tomato fruit during postharvest life.
abstract: In this study, the effect of melatonin on the postharvest ripening and quality improvement of tomato fruit was carried out. The tomatoes were immersed in exogenous melatonin for 2h, and then the related physiological indicators and the expression of genes during post-harvest life were evaluated. Compared with control check (CK), the 50 µM melatonin treatment significantly increased lycopene levels by 5.8-fold. Meanwhile, the key genes involved in fruit colour development, including phytoene synthase1 (PSY1) and carotenoid isomerase (CRTISO), showed a 2-fold increase in expression levels. The rate of water loss from tomato fruit also increased 8.3%, and the expression of aquaporin genes, such as SlPIP12Q, SlPIPQ, SlPIP21Q, and SlPIP22, was up-regulated 2- to 3-fold under 50 µM melatonin treatment. In addition, 50 µM melatonin treatment enhanced fruit softening, increased water-soluble pectin by 22.5%, and decreased protopectin by 19.5%. The expression of the cell wall modifying proteins polygalacturonase (PG), pectin esterase1 (PE1), β-galactosidase (TBG4), and expansin1 (Exp1) was up-regulated under 50 µM melatonin treatment. Melatonin increased ethylene production by 27.1%, accelerated the climacteric phase, and influenced the ethylene signalling pathway. Alteration of ethylene production correlated with altered 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS4) expression. The expression of ethylene signal transduction-related genes such as NR, SlETR4, SlEIL1, SlEIL3, and SlERF2, was enhanced by 50 µM melatonin. The effect of melatonin on ethylene biosynthesis, ethylene perception, and ethylene signalling may contribute to fruit ripening and quality improvement in tomato. This research may promote the application of melatonin on postharvest ripening and quality improvement of tomato fruit as well as other horticultural productions in the future.
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Sun
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Haijun
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Dianbo
authors.initials: D
authors.lastname: Li
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Shi
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Ren
authors.initials: R
authors.lastname: Li
authors.affiliation: School of Agriculture, Virginia State University, Petersburg, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Weeda
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China yaguo@cau.edu.cn zhaobing@cau.edu.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhao
authors.affiliation: School of Agriculture, Virginia State University, Petersburg, USA.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Ren
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing, China yaguo@cau.edu.cn zhaobing@cau.edu.cn.
authors.forename: Yang-Dong
authors.initials: YD
authors.lastname: Guo
mesh_terms: D002338:Carotenoids / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D005030:Ethylenes / Q000096:biosynthesis; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D008550:Melatonin / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D018526:Plant Transpiration; D015854:Up-Regulation
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D002338:Carotenoids; C036216:ethylene; D008550:Melatonin; D000077276:Lycopene
keywords: Ethylene; gene expression; melatonin; postharvest; ripening; tomato.