title: Polyamines function in stress tolerance: from synthesis to regulation.
abstract: Plants are challenged by a variety of biotic or abiotic stresses, which can affect their growth and development, productivity, and geographic distribution. In order to survive adverse environmental conditions, plants have evolved various adaptive strategies, among which is the accumulation of metabolites that play protective roles. A well-established example of the metabolites that are involved in stress responses, or stress tolerance, is the low-molecular-weight aliphatic polyamines, including putrescine, spermidine, and spermine. The critical role of polyamines in stress tolerance is suggested by several lines of evidence: firstly, the transcript levels of polyamine biosynthetic genes, as well as the activities of the corresponding enzymes, are induced by stresses; secondly, elevation of endogenous polyamine levels by exogenous supply of polyamines, or overexpression of polyamine biosynthetic genes, results in enhanced stress tolerance; and thirdly, a reduction of endogenous polyamines is accompanied by compromised stress tolerance. A number of studies have demonstrated that polyamines function in stress tolerance largely by modulating the homeostasis of reactive oxygen species (ROS) due to their direct, or indirect, roles in regulating antioxidant systems or suppressing ROS production. The transcriptional regulation of polyamine synthesis by transcription factors is also reviewed here. Meanwhile, future perspectives on polyamine research are also suggested.
authors.affiliation: Key Laboratory of Horticultural Plant Biology, College of Horticulture and Forestry Science, Huazhong Agricultural University , Wuhan, China.
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Liu
authors.affiliation: Key Laboratory of Horticultural Plant Biology, College of Horticulture and Forestry Science, Huazhong Agricultural University , Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Key Laboratory of Horticultural Plant Biology, College of Horticulture and Forestry Science, Huazhong Agricultural University , Wuhan, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Key Laboratory of Horticultural Plant Biology, College of Horticulture and Forestry Science, Huazhong Agricultural University , Wuhan, China ; State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University , Yangling, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Gong
authors.affiliation: National Institute of Fruit Tree Science, National Agriculture and Food Research Organization , Tsukuba, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Moriguchi
keywords: ROS; abiotic stress; antioxidant; polyamine; polyamine biosynthesis; transcriptional regulation