title: Gene expression responses of paper birch (Betula papyrifera) to elevated CO2 and O3 during leaf maturation and senescence.
abstract: Gene expression responses of paper birch (Betula papyrifera) leaves to elevated concentrations of CO(2) and O(3) were studied with microarray analyses from three time points during the summer of 2004 at Aspen FACE. Microarray data were analyzed with clustering techniques, self-organizing maps, K-means clustering and Sammon's mappings, to detect similar gene expression patterns within sampling times and treatments. Most of the alterations in gene expression were caused by O(3), alone or in combination with CO(2). O(3) induced defensive reactions to oxidative stress and earlier leaf senescence, seen as decreased expression of photosynthesis- and carbon fixation-related genes, and increased expression of senescence-associated genes. The effects of elevated CO(2) reflected surplus of carbon that was directed to synthesis of secondary compounds. The combined CO(2)+O(3) treatment resulted in differential gene expression than with individual gas treatments or in changes similar to O(3) treatment, indicating that CO(2) cannot totally alleviate the harmful effects of O(3).
authors.affiliation: Finnish Forest Research Institute, Suonenjoki, Finland. sari.kontunen-soppela@joensuu.fi
authors.forename: Sari
authors.initials: S
authors.lastname: Kontunen-Soppela
authors.forename: Juha
authors.initials: J
authors.lastname: Parviainen
authors.forename: Hanna
authors.initials: H
authors.lastname: Ruhanen
authors.forename: Mikael
authors.initials: M
authors.lastname: Brosché
authors.forename: Markku
authors.initials: M
authors.lastname: Keinänen
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Thakur
authors.forename: Mikko
authors.initials: M
authors.lastname: Kolehmainen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kangasjärvi
authors.forename: Elina
authors.initials: E
authors.lastname: Oksanen
authors.forename: David F
authors.initials: DF
authors.lastname: Karnosky
authors.forename: Elina
authors.initials: E
authors.lastname: Vapaavuori
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D029662:Betula / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D002245:Carbon Dioxide / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D010126:Ozone / Q000633:toxicity*; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development
chemical_list: D000393:Air Pollutants; D002245:Carbon Dioxide; D010126:Ozone