title: PpCBF3 from Cold-Tolerant Kentucky Bluegrass Involved in Freezing Tolerance Associated with Up-Regulation of Cold-Related Genes in Transgenic Arabidopsis thaliana.
abstract: Dehydration-Responsive Element Binding proteins (DREB)/C-repeat (CRT) Binding Factors (CBF) have been identified as transcriptional activators during plant responses to cold stress. The objective of this study was to determine the physiological roles of a CBF gene isolated from a cold-tolerant perennial grass species, Kentucky bluegrass (Poa pratensis L.), which designated as PpCBF3, in regulating plant tolerance to freezing stress. Transient transformation of Arabidopsis thaliana mesophyll protoplast with PpCBF3-eGFP fused protein showed that PpCBF3 was localized to the nucleus. RT-PCR analysis showed that PpCBF3 was specifically induced by cold stress (4°C) but not by drought stress [induced by 20% polyethylene glycol 6000 solution (PEG-6000)] or salt stress (150 mM NaCl). Transgenic Arabidopsis overexpressing PpCBF3 showed significant improvement in freezing (-20°C) tolerance demonstrated by a lower percentage of chlorotic leaves, lower cellular electrolyte leakage (EL) and H2O2 and O2.- content, and higher chlorophyll content and photochemical efficiency compared to the wild type. Relative mRNA expression level analysis by qRT-PCR indicated that the improved freezing tolerance of transgenic Arabidopsis plants overexpressing PpCBF3 was conferred by sustained activation of downstream cold responsive (COR) genes. Other interesting phenotypic changes in the PpCBF3-transgenic Arabidopsis plants included late flowering and slow growth or 'dwarfism', both of which are desirable phenotypic traits for perennial turfgrasses. Therefore, PpCBF3 has potential to be used in genetic engineering for improvement of turfgrass freezing tolerance and other desirable traits.
authors.affiliation: College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhuang
authors.affiliation: College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Yuan
authors.affiliation: College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.affiliation: College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, PR China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, United States of America.
authors.forename: Bingru
authors.initials: B
authors.lastname: Huang
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D004573:Electrolytes / Q000378:metabolism; D035264:Flowers / Q000502:physiology; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D031785:Poa / Q000235:genetics*; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D013347:Subcellular Fractions / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D004573:Electrolytes; D010940:Plant Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D002734:Chlorophyll; D049452:Green Fluorescent Proteins