title: PtrABF of Poncirus trifoliata functions in dehydration tolerance by reducing stomatal density and maintaining reactive oxygen species homeostasis.
abstract: Abscisic acid-responsive element (ABRE)-binding factors (ABFs) play important roles in abiotic stress responses; however, the underlying mechanisms are poorly understood. In this study, it is reported that overexpression of Poncirus trifoliata PtrABF significantly enhanced dehydration tolerance. The transgenic lines displayed smaller stomatal apertures, reduced stomatal density/index, and lower expression levels of genes associated with stomatal development. PtrABF was found to interact with PtrICE1, a homologue of ICE1 (Inducer of CBF Expression 1) that has been shown to be critical for stomatal development. Microarray analysis revealed that a total of 70 genes were differentially expressed in the transgenic line, 42 induced and 28 repressed. At least two units of ABREs and coupling elements were present in the promoters of most of the induced genes, among which peroxidase and arginine decarboxylase were verified as bona fide targets of PtrABF. Transgenic plants exhibited higher antioxidant enzyme activities and free polyamine levels, but lower levels of reactive oxygen species (ROS) and malondialdehyde. Polyamines were revealed to be associated with ROS scavenging in the transgenic plants due to a modulation of antioxidant enzymes triggered by signalling mediated by H2O2 derived from polyamine oxidase (PAO)-mediated catabolism. Taken together, the results indicate that PtrABF functions positively in dehydration tolerance by limiting water loss through its influence on stomatal movement or formation and maintaining ROS homeostasis via modulation of antioxidant enzymes and polyamines through transcriptional regulation of relevant target genes.
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Min
authors.initials: M
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: Jianbing
authors.initials: J
authors.lastname: Hu
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Wei
authors.initials: W
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: Xingzheng
authors.initials: X
authors.lastname: Fu
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: D000222:Adaptation, Physiological; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D054046:Plant Stomata / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D032104:Poncirus / Q000235:genetics / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D017382:Reactive Oxygen Species
keywords: ABRE; Poncirus trifoliata; ROS; antioxidant enzyme; arginine decarboxylase; polyamine; polyamine oxidase; stomatal development.