title: Characterization of chilling-shock responses in four genotypes of Miscanthus reveals the superior tolerance of M. x giganteus compared with M. sinensis and M. sacchariflorus.
abstract: OBJECTIVE
  The bioenergy grass Miscanthus is native to eastern Asia. As Miscanthus uses C4 photosynthesis, the cooler temperatures experienced in much of northern Europe are expected to limit productivity. Identification of genetic diversity in chilling tolerance will enable breeders to generate more productive varieties for these cooler regions. Characterizing the temporal relationships between photosynthesis, carbohydrate and molecular expression of relevant genes is key to understanding genotypic differences in tolerance or sensitivity.
  
  
  METHODS
  To characterize chilling responses in four Miscanthus genotypes, plants were exposed to a sudden reduction in temperature. The genotypes studied comprised of two M. sinensis, one M. sacchariflorus and one inter-species hybrid, M. × giganteus. Changes in photosynthesis (Asat), carbohydrate composition and the expression of target transcripts were observed following chilling-shock. After 4 d the decline in leaf elongation rate (LER) in the different genotypes was measured.
  
  
  RESULTS
  Following chilling-shock the greatest decline in Asat was observed in M. sacchariflorus and one M. sinensis genotype. Carbohydrate concentrations increased in all genotypes following chilling but to a lesser extent in M. sacchariflorus. Two stress inducible genes were most highly expressed in the genotypes that experienced the greatest declines in Asat and LER. Miscanthus × giganteus retained the highest Asat and was unique in exhibiting no decline in LER following transfer to 12 °C.
  
  
  CONCLUSIONS
  Miscanthus × giganteus exhibits a superior tolerance to chilling shock than other genotypes of Miscanthus. The absence of sucrose accumulation in M. sacchariflorus during chilling-shock suggests an impairment in enzyme function. A candidate transcription factor, MsCBF3, is most highly expressed in the most sensitive genotypes and may be a suitable molecular marker for predicting chilling sensitivity.
authors.affiliation: Institute of Biological, Environmental and Rural Sciences IBERS, Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion SY23 3EE, UK. sap@aber.ac.uk
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Purdy
authors.forename: Anne Louise
authors.initials: AL
authors.lastname: Maddison
authors.forename: Laurence Edmund
authors.initials: LE
authors.lastname: Jones
authors.forename: Richard John
authors.initials: RJ
authors.lastname: Webster
authors.forename: John
authors.initials: J
authors.lastname: Andralojc
authors.forename: Iain
authors.initials: I
authors.lastname: Donnison
authors.forename: John
authors.initials: J
authors.lastname: Clifton-Brown
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000528:radiation effects; D050260:Carbohydrate Metabolism / Q000528:radiation effects; D003080:Cold Temperature; D058639:Cold-Shock Response / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D003433:Crosses, Genetic; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D005838:Genotype; D008027:Light; D010641:Phenotype; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D006109:Poaceae / Q000235:genetics* / Q000502:physiology* / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012995:Solubility; D013213:Starch / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D013213:Starch