title: Long-term growth under elevated CO2 suppresses biotic stress genes in non-acclimated, but not cold-acclimated winter wheat.
abstract: This study compared the photosynthetic performance and the global gene expression of the winter hardy wheat Triticum aestivum cv Norstar grown under non-acclimated (NA) or cold-acclimated (CA) conditions at either ambient CO2 or elevated CO2. CA Norstar maintained comparable light-saturated and CO2-saturated rates of photosynthesis but lower quantum requirements for PSII and non-photochemical quenching relative to NA plants even at elevated CO2. Neither NA nor CA plants were sensitive to feedback inhibition of photosynthesis at elevated CO2. Global gene expression using microarray combined with bioinformatics analysis revealed that genes affected by elevated CO2 were three times higher in NA (1,022 genes) compared with CA (372 genes) Norstar. The most striking effect was the down-regulation of genes involved in the plant defense responses in NA Norstar. In contrast, cold acclimation reversed this down-regulation due to the cold induction of genes involved in plant pathogenesis resistance; and cellular and chloroplast protection. These results suggest that elevated CO2 has less impact on plant performance and productivity in cold-adapted winter hardy plants in the northern climates compared with warmer environments. Selection for cereal cultivars with constitutively higher expression of biotic stress defense genes may be necessary under elevated CO2 during the warm growth period and in warmer climates.
authors: Département des Sciences biologiques, Université du Québec à Montréal, CP 8888 Succursale Centre-Ville, Montréal, Québec, Canada H3C 3P8.
authors: Khalil
authors: K
authors: Kane
authors: Keshav P
authors: KP
authors: Dahal
authors: Mohamed A
authors: MA
authors: Badawi
authors: Mario
authors: M
authors: Houde
authors: Norman P A
authors: NP
authors: Hüner
authors: Fathey
authors: F
authors: Sarhan
mesh_terms: D000064:Acclimatization; D002245:Carbon Dioxide / Q000494:pharmacology*; D015536:Down-Regulation; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008027:Light; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics; D018526:Plant Transpiration; D012621:Seasons; D013312:Stress, Physiological; D013696:Temperature; D059467:Transcriptome; D014908:Triticum / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D015854:Up-Regulation
chemical_list: D010940:Plant Proteins; D002245:Carbon Dioxide
keywords: Cold acclimation; Defense-related genes; Long-term elevated CO2; Microarrays; Photosynthesis; Triticum aestivum