Identification and characterization of novel senescence-associated genes from barley (Hordeum vulgare) primary leaves.
Leaf senescence is the final developmental stage of a leaf. The progression of barley primary leaf senescence was followed by measuring the senescence-specific decrease in chlorophyll content and photosystem II efficiency. In order to isolate novel factors involved in leaf senescence, a differential display approach with mRNA populations from young and senescing primary barley leaves was applied. In this approach, 90 senescence up-regulated cDNAs were identified. Nine of these clones were, after sequence analyses, further characterized. The senescence-associated expression was confirmed by Northern analyses or quantitative RealTime-PCR. In addition, involvement of the phytohormones ethylene and abscisic acid in regulation of these nine novel senescence-induced cDNA fragments was investigated. Two cDNA clones showed homologies to genes with a putative regulatory function. Two clones possessed high homologies to barley retroelements, and five clones may be involved in degradation or transport processes. One of these genes was further analysed. It encodes an ADP ribosylation factor 1-like protein (HvARF1) and includes sequence motifs representing a myristoylation site and four typical and well conserved ARF-like protein domains. The localization of the protein was investigated by confocal laser scanning microscopy of onion epidermal cells after particle bombardment with chimeric HvARF1-GFP constructs. Possible physiological roles of these nine novel SAGs during barley leaf senescence are discussed.
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Institute of Plant Physiology, Martin-Luther University Halle-Wittenberg, Weinbergweg 10, Halle, Germany.
Clauss
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Barth
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Humbeck
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D020823:ADP-Ribosylation Factor 1 / Q000032:analysis / Q000737:chemistry / Q000502:physiology; D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D016922:Cellular Senescence / Q000235:genetics*; D002734:Chlorophyll / Q000378:metabolism; D003001:Cloning, Molecular; D005030:Ethylenes / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000032:analysis; D001467:Hordeum / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D019697:Onions / Q000235:genetics; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D005030:Ethylenes; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D002734:Chlorophyll; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid; C036216:ethylene; D020823:ADP-Ribosylation Factor 1