title: PtrA/NINV, an alkaline/neutral invertase gene of Poncirus trifoliata, confers enhanced tolerance to multiple abiotic stresses by modulating ROS levels and maintaining photosynthetic efficiency.
abstract: BACKGROUND
  Alkaline/neutral invertase (A/N-INV), an enzyme that hydrolyzes sucrose irreversibly into glucose and fructose, is essential for normal plant growth,development, and stress tolerance. However, the physiological and/or molecular mechanism underpinning the role of A/N-INV in abiotic stress tolerance is poorly understood.
  
  
  RESULTS
  In this report, an A/N-INV gene (PtrA/NINV) was isolated from Poncirus trifoliata, a cold-hardy relative of citrus, and functionally characterized. PtrA/NINV expression levels were induced by cold, salt, dehydration, sucrose, and ABA, but decreased by glucose. PtrA/NINV was found to localize in both chloroplasts and mitochondria. Overexpression of PtrA/NINV conferred enhanced tolerance to multiple stresses, including cold, high salinity, and drought, as supported by lower levels of reactive oxygen species (ROS), reduced oxidative damages, decreased water loss rate, and increased photosynthesis efficiency, relative to wild-type (WT). The transgenic plants exhibited higher A/N-INV activity and greater reducing sugar content under normal and stress conditions.
  
  
  CONCLUSIONS
  PtrA/NINV is an important gene implicated in sucrose decomposition, and plays a positive role in abiotic stress tolerance by promoting osmotic adjustment, ROS detoxification and photosynthesis efficiency. Thus, PtrA/NINV has great potential to be used in transgenic breeding for improvement of stress tolerance.
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.|Department of Horticulture, Faculty of Agriculture, Tishreen University, Lattakia, Syria.
authors.forename: Bachar
authors.initials: B
authors.lastname: Dahro
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Peng
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China. liujihong@mail.hzau.edu.cn.
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Liu
mesh_terms: D003080:Cold Temperature; D010788:Photosynthesis; D032104:Poncirus / Q000201:enzymology* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013312:Stress, Physiological; D043324:beta-Fructofuranosidase / Q000235:genetics*
chemical_list: D017382:Reactive Oxygen Species; D043324:beta-Fructofuranosidase
keywords: Abiotic stress; Alkaline/neutral invertase; Photosynthetic efficiency; Poncirus trifoliata; ROS homeostasis; Sucrose metabolism