Differential induction of mitochondrial machinery by light intensity correlates with changes in respiratory metabolism and photorespiration in rice leaves.
The light responsiveness of mitochondrial function was investigated through changes in mitochondrial composition and metabolism in rice (Oryza sativa) shoots. The mitochondrial proteome and metabolite abundances under low light, (LL, 100 μmol m(-2) s(-1) ), and high light (HL, 700 μmol m(-2) s(-1) ) were measured along with information on shoot photosynthetic, respiratory and photorespiratory activity. Specific steps in mitochondrial tricarboxylic acid (TCA) cycle metabolism were decreased under HL, correlating with lower respiration rate under HL. The abundance of mitochondrial enzymes in branch chain metabolism was reduced under HL/LL, and correlated with a decrease in the abundance of a range of amino acids in the HL/LL. Mitochondrial nucleoside diphosphate kinase was increased under LL/HL treatments. Significant accumulation of glycine decarboxylase P, T subunits and serine hydroxymethyltransferase occurred in response to light. The abundance of the glycine decarboxylase (GDC) H subunit proteins was not changed by HL/LL treatments, and the abundance of GDC L subunit protein was halved under HL, indicating a change in the stoichiometry of GDC subunits, while photorespiration was fourfold higher in LL- than in HL-treated plants. Insights into these light-dependent phenomena and their importance for understanding the initiation of photorespiration in rice and adaptation of mitochondria to function in photosynthetic cells are discussed.
ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Shaobai
S
Huang
ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Richard P
RP
Jacoby
ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Rachel N
RN
Shingaki-Wells
ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Lei
L
Li
ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia.
A Harvey
AH
Millar
D000596:Amino Acids / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism; D019069:Cell Respiration / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D008027:Light; D008928:Mitochondria / Q000378:metabolism* / Q000528:radiation effects; D012275:Oryza / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects*; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000502:physiology* / Q000528:radiation effects*; D010940:Plant Proteins / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism / Q000528:radiation effects; D018087:Plastids / Q000378:metabolism / Q000528:radiation effects; D020543:Proteome / Q000378:metabolism
D000596:Amino Acids; D002264:Carboxylic Acids; D010940:Plant Proteins; D020543:Proteome; D002734:Chlorophyll