Reduction of ribulose-1,5-bisphosphate carboxylase/oxygenase by antisense RNA in the C4 plant Flaveria bidentis leads to reduced assimilation rates and increased carbon isotope discrimination

Transgenic Flaveria bidentis (a C4 species) plants with an antisense gene directed against the mRNA of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) were used to examine the relationship between the CO2 assimilation rate, Rubisco content, and carbon isotope discrimination. Reduction in t...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1997-02, Vol.113 (2), p.469-477
Main Authors: Von Caemmerer, S. (Australian National University, Canberra, Australia.), Millgate, A, Farquhar, G.D, Furbank, R.T
Format: Article
Language:English
Subjects:
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
ARN
Biochemistry and Enzymology
Biological and medical sciences
C4 photosynthesis
C4 plants
Carbon dioxide
Carbon isotopes
CARBONE
CARBONO
Carboxylation
COMPOSITAE
ECHANGE GAZEUX
Enzymes
FEUILLE
FOTOSINTESIS
Fundamental and applied biological sciences. Psychology
GENETICA
GENETIQUE
HOJAS
INTERCAMBIO DE GASES
ION
IONES
ISOTOPE
ISOTOPOS
Leaves
MATEMATICAS
MATHEMATIQUE
MEDICION
Mesophyll
MESURE
Metabolism
MODELE MATHEMATIQUE
MODELOS MATEMATICOS
PHOTOSYNTHESE
Photosynthesis, respiration. Anabolism, catabolism
Plant biochemistry
Plant physiology and development
PLANTAS TRANSGENICAS
PLANTE TRANSGENIQUE
Plants
REDUCCION
REDUCTION
RUBISCO
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Summary:Transgenic Flaveria bidentis (a C4 species) plants with an antisense gene directed against the mRNA of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) were used to examine the relationship between the CO2 assimilation rate, Rubisco content, and carbon isotope discrimination. Reduction in the amount of Rubisco in the transgenic plants resulted in reduced CO2 assimilation rates and increased carbon isotope discrimination of leaf dry matter. The H2O exchange was similar in transgenic and wild-type plants, resulting in higher ratios of intercellular to ambient CO2 partial pressures. Carbon isotope discrimination was measured concurrently with CO2 and H2O exchange on leaves of the control plants and T1 progeny with a 40% reduction in Rubisco. From the theory of carbon isotope discrimination in the C4 species, we conclude that the reduction in the Rubisco content in the transgenic plants has led to an increase in bundle-sheath CO2 concentration and CO2 leakage from the bundle sheath; however, some down-regulation of the C4 cycle also occurred
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.113.2.469