The early light-induced protein is also produced during leaf senescence of Nicotiana tabacum.
To better understand the genetic controls of leaf senescence, a tobacco (Nicotiana tabacum L. cv. SR1) mRNA that is up-regulated during senescence was isolated by the cDNA-amplified restriction fragment polymorphism method and the cDNA was cloned. The mRNA coded for the early light-induced protein (ELIP), a member of the chlorophyll a/b-binding protein family that has been implicated in assembly or repair of the photosynthetic machinery during early chloroplast development and abiotic stress. A protein antigenically recognized by antibodies to ELIP appeared during senescence with kinetics similar to those of its mRNA. The mRNA, designated ELIP-TOB, was detected earlier when senescence was enhanced by leaf detachment and treatment with 1-amino-cyclopropane-1-carboxylic acid, and was detected later when senescence was retarded by benzyladenine. However, no ELIP-TOB mRNA was seen in the dark even though senescence was accelerated under these conditions. Furthermore, water stress and anaerobiosis stimulated the appearance of ELIP-TOB mRNA before losses of chlorophyll could be detected. We discuss the conditions that may lead to the up-regulation of ELIP-TOB during senescence and speculate as to the role of the gene product in this terminal phase of leaf development.
Binyamin
L
L
Faculty of Biology, Technion, Israel Institute of Technology, Haifa.
Falah
M
M
Portnoy
V
V
Soudry
E
E
Gepstein
S
S
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000693:Anaerobiosis / Q000502:physiology; D017209:Apoptosis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000378:metabolism; D016922:Cellular Senescence / Q000502:physiology; D002736:Chloroplasts / Q000502:physiology; D003001:Cloning, Molecular; D018076:DNA, Complementary; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D010947:Plants, Toxic; D012150:Polymorphism, Restriction Fragment Length; D018749:RNA, Plant / Q000302:isolation & purification; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism
D029681:Arabidopsis Proteins; C423618:CAB2 protein, Arabidopsis; D002352:Carrier Proteins; D018076:DNA, Complementary; C078410:ELIP protein, Arabidopsis; D045342:Light-Harvesting Protein Complexes; D010940:Plant Proteins; D018749:RNA, Plant; D014867:Water