title: Ectopic AtCBF1 over-expression enhances freezing tolerance and induces cold acclimation-associated physiological modifications in potato.
abstract: We studied the effect of ectopic AtCBF over-expression on physiological alterations that occur during cold exposure in frost-sensitive Solanum tuberosum and frost-tolerant Solanum commersonii. Relative to wild-type plants, ectopic AtCBF1 over-expression induced expression of COR genes without a cold stimulus in both species, and imparted a significant freezing tolerance gain in both species: 2 degrees C in S. tuberosum and up to 4 degrees C in S. commersonii. Transgenic S. commersonii displayed improved cold acclimation potential, whereas transgenic S. tuberosum was still incapable of cold acclimation. During cold treatment, leaves of wild-type S. commersonii showed significant thickening resulting from palisade cell lengthening and intercellular space enlargement, whereas those of S. tuberosum did not. Ectopic AtCBF1 activity induced these same leaf alterations in the absence of cold in both species. In transgenic S. commersonii, AtCBF1 activity also mimicked cold treatment by increasing proline and total sugar contents in the absence of cold. Relative to wild type, transgenic S. commersonii leaves were darker green, had higher chlorophyll and lower anthocyanin levels, greater stomatal numbers, and displayed greater photosynthetic capacity, suggesting higher productivity potential. These results suggest an endogenous CBFpathway is involved in many of the structural, biochemical and physiological alterations associated with cold acclimation in these Solanum species.
authors.affiliation: Department of Horticulture, ALS 4017, Oregon State University, Corvalis, OR 97331, USA, and Institute of Agricultural Research, INIA, Satntiago, Chile.
authors.forename: María-Teresa
authors.initials: MT
authors.lastname: Pino
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Skinner
authors.forename: Zoran
authors.initials: Z
authors.lastname: Jeknić
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Hayes
authors.forename: Alfred H
authors.initials: AH
authors.lastname: Soeldner
authors.forename: Michael F
authors.initials: MF
authors.lastname: Thomashow
authors.forename: Tony H H
authors.initials: TH
authors.lastname: Chen
mesh_terms: D000064:Acclimatization / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005615:Freezing; D015870:Gene Expression; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism / Q000648:ultrastructure; D018547:Plant Stems / Q000378:metabolism; D030821:Plants, Genetically Modified; D032322:Solanum / Q000235:genetics* / Q000502:physiology*; D013045:Species Specificity; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C104387:CBF1 protein, Arabidopsis; D004268:DNA-Binding Proteins; C114578:DREB1A protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; D002734:Chlorophyll