title: SAUR36, a small auxin up RNA gene, is involved in the promotion of leaf senescence in Arabidopsis.
abstract: Small Auxin Up RNA genes (SAURs) are early auxin-responsive genes, but whether any of them are involved in leaf senescence is not known. Auxin, on the other hand, has been shown to have a role in leaf senescence. Some of the external application experiments indicated that auxin can inhibit leaf senescence, whereas other experiments indicated that auxin can promote leaf senescence. Here, we report the identification and characterization of an Arabidopsis (Arabidopsis thaliana) leaf senescence-associated gene named SAG201, which is highly up-regulated during leaf senescence and can be induced by 1-naphthaleneacetic acid, a synthetic auxin. It encodes a functionally uncharacterized SAUR that has been annotated as SAUR36. Leaf senescence in transfer DNA insertion saur36 knockout lines was delayed as revealed by analyses of chlorophyll content, F(v)/F(m) ratio (a parameter for photosystem II activity), ion leakage, and the expression of leaf senescence marker genes. In contrast, transgenic Arabidopsis plants overexpressing SAUR36 (without its 3' untranslated region [UTR]) displayed an early leaf senescence phenotype. However, plants overexpressing SAUR36 with its 3' UTR were normal and did not exhibit the early-senescence phenotype. These data suggest that SAUR36 is a positive regulator of leaf senescence and may mediate auxin-induced leaf senescence and that the 3' UTR containing a highly conserved downstream destabilizes the SAUR36 transcripts in young leaves.
authors.affiliation: Department of Horticulture, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Hou
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Su-Sheng
authors.initials: SS
authors.lastname: Gan
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D002734:Chlorophyll / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D012313:RNA / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010937:Plant Growth Regulators; C036483:T-DNA; D002734:Chlorophyll; C034182:1-naphthaleneacetic acid; D012313:RNA