caa a22 4500 445890231 CHVBK 20180317145614.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-011-9651-3 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9651-3 Peroxisomal hydroxypyruvate reductase is not essential for photorespiration in Arabidopsis but its absence causes an increase in the stoichiometry of photorespiratory CO2 release [Elektronische Daten] [Asaph Cousins, Berkley Walker, Itsara Pracharoenwattana, Steven Smith, Murray Badger] Recycling of carbon by the photorespiratory pathway involves enzymatic steps in the chloroplast, mitochondria, and peroxisomes. Most of these reactions are essential for plants growing under ambient CO2 concentrations. However, some disruptions of photorespiratory metabolism cause subtle phenotypes in plants grown in air. For example, Arabidopsis thaliana lacking both of the peroxisomal malate dehydrogenase genes (pmdh1pmdh2) or hydroxypyruvate reductase (hpr1) are viable in air and have rates of photosynthesis only slightly lower than wild-type plants. To investigate how disruption of the peroxisomal reduction of hydroxypyruvate to glycerate influences photorespiratory carbon metabolism we analyzed leaf gas exchange in A. thaliana plants lacking peroxisomal HPR1 expression. In addition, because the lack of HPR1 could be compensated for by other reactions within the peroxisomes using reductant supplied by PMDH a triple mutant lacking expression of both peroxisomal PMDH genes and HPR1 (pmdh1pmdh2hpr1) was analyzed. Rates of photosynthesis under photorespiratory conditions (ambient CO2 and O2 concentrations) were slightly reduced in the hpr1 and pmdh1pmdh2hpr1 plants indicating other reactions can help bypass this disruption in the photorespiratory pathway. However, the CO2 compensation points (Γ) increased under photorespiratory conditions in both mutants indicating changes in photorespiratory carbon metabolism in these plants. Measurements of Γ*, the CO2 compensation point in the absence of mitochondrial respiration, and the CO2 released per Rubisco oxygenation reaction demonstrated that the increase in Γ in the hpr1 and pmdh1pmdh2hpr1 plants is not associated with changes in mitochondrial respiration but with an increase in the non-respiratory CO2 released per Rubisco oxygenation reaction. Springer Science+Business Media B.V., 2011 Photosynthesis nationallicence Photorespiration nationallicence Peroxisomes nationallicence Hydroxypyruvate reductase nationallicence Cousins Asaph School of Biological Sciences, Molecular Plant Sciences, Washington State University, 99164-4236, Pullman, WA, USA aut Walker Berkley School of Biological Sciences, Molecular Plant Sciences, Washington State University, 99164-4236, Pullman, WA, USA aut Pracharoenwattana Itsara Australian Research Council Centre of Excellence in Plant Energy Biology, and Centre of Excellence for Plant Metabolomics, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia aut Smith Steven Australian Research Council Centre of Excellence in Plant Energy Biology, and Centre of Excellence for Plant Metabolomics, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia aut Badger Murray Australian Research Council Centre of Excellence In Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 91-100 0166-8595 108:2-3<91 2011 108 11120 https://doi.org/10.1007/s11120-011-9651-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9651-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Cousins Asaph School of Biological Sciences, Molecular Plant Sciences, Washington State University, 99164-4236, Pullman, WA, USA aut NATIONALLICENCE 700 1- Walker Berkley School of Biological Sciences, Molecular Plant Sciences, Washington State University, 99164-4236, Pullman, WA, USA aut NATIONALLICENCE 700 1- Pracharoenwattana Itsara Australian Research Council Centre of Excellence in Plant Energy Biology, and Centre of Excellence for Plant Metabolomics, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia aut NATIONALLICENCE 700 1- Smith Steven Australian Research Council Centre of Excellence in Plant Energy Biology, and Centre of Excellence for Plant Metabolomics, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, WA, Australia aut NATIONALLICENCE 700 1- Badger Murray Australian Research Council Centre of Excellence In Plant Energy Biology, Molecular Plant Physiology Group, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 91-100 0166-8595 108:2-3<91 2011 108 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer