title: Senescence-associated gene expression during ozone-induced leaf senescence in Arabidopsis.
abstract: The expression patterns of senescence-related genes were determined during ozone (O(3)) exposure in Arabidopsis. Rosettes were treated with 0.15 microL L(-1) O(3) for 6 h d(-1) for 14 d. O(3)-treated leaves began to yellow after 10 d of exposure, whereas yellowing was not apparent in control leaves until d 14. Transcript levels for eight of 12 senescence related genes characterized showed induction by O(3). SAG13 (senescence-associated gene), SAG21, ERD1 (early responsive to dehydration), and BCB (blue copper-binding protein) were induced within 2 to 4 d of O(3) treatment; SAG18, SAG20, and ACS6 (ACC synthase) were induced within 4 to 6 d; and CCH (copper chaperone) was induced within 6 to 8 d. In contrast, levels of photosynthetic gene transcripts, rbcS (small subunit of Rubisco) and cab (chlorophyll a/b-binding protein), declined after 6 d. Other markers of natural senescence, SAG12, SAG19, MT1 (metallothionein), and Atgsr2 (glutamine synthetase), did not show enhanced transcript accumulation. When SAG12 promoter-GUS (beta-glucuronidase) and SAG13 promoter-GUS transgenic plants were treated with O(3), GUS activity was induced in SAG13-GUS plants after 2 d but was not detected in SAG12-GUS plants. SAG13 promoter-driven GUS activity was located throughout O(3)-treated leaves, whereas control leaves generally showed activity along the margins. The acceleration of leaf senescence induced by O(3) is a regulated event involving many genes associated with natural senescence.
authors.affiliation: Intercollege Graduate Program in Plant Physiology, The Pennsylvania State University, University Park 16802, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Miller
authors.forename: R N
authors.initials: RN
authors.lastname: Arteca
authors.forename: E J
authors.initials: EJ
authors.lastname: Pell
mesh_terms: D000426:Alcohol Dehydrogenase / Q000096:biosynthesis; D017360:Arabidopsis / Q000187:drug effects*; D016922:Cellular Senescence; D003546:Cysteine Endopeptidases / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant; D010126:Ozone / Q000494:pharmacology*; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects*; D010940:Plant Proteins / Q000096:biosynthesis; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis; D015398:Signal Transduction
chemical_list: D010940:Plant Proteins; D010126:Ozone; D000426:Alcohol Dehydrogenase; D003546:Cysteine Endopeptidases; D012273:Ribulose-Bisphosphate Carboxylase