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Reductions of Rubisco Activase by Antisense RNA in the C4 Plant Flaveria bidentis Reduces Rubisco Carbamylation and Leaf Photosysthesis

von Caemmerer, Susanne; Hendrickson, Luke; Quinn, Vanda; Vella, N; Millgate, A G; Furbank, Robert Thomas

Description

To function, the catalytic sites of Rubisco (EC 4.1.1.39) need to be activated by the reversible carbamylation of a lysine residue within the sites followed by rapid binding of magnesium. The activation of Rubisco in vivo requires the presence of the regulatory protein Rubisco activase. This enzyme is thought to aid the release of sugar phosphate inhibitors from Rubisco's catalytic sites, thereby influencing carbamylation. In C3 species, Rubisco operates in a low CO2 environment, which is...[Show more]

dc.contributor.authorvon Caemmerer, Susanne
dc.contributor.authorHendrickson, Luke
dc.contributor.authorQuinn, Vanda
dc.contributor.authorVella, N
dc.contributor.authorMillgate, A G
dc.contributor.authorFurbank, Robert Thomas
dc.date.accessioned2015-12-13T23:00:25Z
dc.identifier.issn0032-0889
dc.identifier.urihttp://hdl.handle.net/1885/84117
dc.description.abstractTo function, the catalytic sites of Rubisco (EC 4.1.1.39) need to be activated by the reversible carbamylation of a lysine residue within the sites followed by rapid binding of magnesium. The activation of Rubisco in vivo requires the presence of the regulatory protein Rubisco activase. This enzyme is thought to aid the release of sugar phosphate inhibitors from Rubisco's catalytic sites, thereby influencing carbamylation. In C3 species, Rubisco operates in a low CO2 environment, which is suboptimal for both catalysis and carbamylation. In C4 plants, Rubisco is located in the bundle sheath cells and operates in a high CO2 atmosphere close to saturation. To explore the role of Rubisco activase in C4 photosynthesis, activase levels were reduced in Flaveria bidentis, a C 4 dicot, by transformation with an antisense gene directed against the mRNA for Rubisco activase. Four primary transformants with very low activase levels were recovered. These plants and several of their segregating T 1 progeny required high CO2 (>1 kPa) for growth. They had very low CO2 assimilation rates at high light and ambient CO 2, and only 10% to 15% of Rubisco sites were carbamylated at both ambient and very high CO2. The amount of Rubisco was similar to that of wild-type plants. Experiments with the T1 progeny of these four primary transformants showed that CO2 assimilation rate and Rubisco carbamylation were severely reduced in plants with less than 30% of wild-type levels of activase. We conclude that activase activity is essential for the operation of the C4 photosynthetic pathway.
dc.publisherAmerican Society of Plant Biologists
dc.sourcePlant Physiology
dc.subjectKeywords: Catalysis; Genes; RNA; Antesense RNA; Rubisco activase; Plants (botany); Nucleic Acids; Plants; Flaveria; Flaveria bidentis; carbon dioxide; complementary RNA; rca protein, plant; ribulosebisphosphate carboxylase; vegetable protein; article; enzymology; F
dc.titleReductions of Rubisco Activase by Antisense RNA in the C4 Plant Flaveria bidentis Reduces Rubisco Carbamylation and Leaf Photosysthesis
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume137
dc.date.issued2005
local.identifier.absfor060104 - Cell Metabolism
local.identifier.absfor070303 - Crop and Pasture Biochemistry and Physiology
local.identifier.ariespublicationMigratedxPub12382
local.type.statusPublished Version
local.contributor.affiliationvon Caemmerer, Susanne, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationHendrickson, Luke, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationQuinn, Vanda, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationVella, N, Macquarie University
local.contributor.affiliationMillgate, A G, CSIRO Division of Plant Industry
local.contributor.affiliationFurbank, Robert Thomas, CSIRO Division of Plant Industry
local.description.embargo2037-12-31
local.bibliographicCitation.startpage747
local.bibliographicCitation.lastpage755
local.identifier.doi10.1104/pp.104.056077
dc.date.updated2015-12-12T07:34:04Z
local.identifier.scopusID2-s2.0-19044392900
CollectionsANU Research Publications

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