Kerchev Pavel, Waszczak Cezary, Lewandowska Aleksandra, Willems Patrick, Shapiguzov Alexey, Li Zhen, Alseekh Saleh, Mühlenbock Per, Hoeberichts Frank A, Huang Jingjing, Van Der Kelen Katrien, Kangasjärvi Jaakko, Fernie Alisdair R, De Smet Riet, Van de Peer Yves, Messens Joris, Van Breusegem Frank
Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.K., C.W., A.L., P.W., Z.L., P.M., F.A.H., K.V.D.K., R.D.S. Y.V.d.P., F.V.B.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.K., C.W., A.L., P.W., Z.L., P.M., F.A.H., K.V.D.K., R.D.S., Y.V.d.P., F.V.B.);Structural Biology Research Center, VIB, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Structural Biology Brussels Laboratory, Vrije Universiteit Brussel, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Brussels Center for Redox Biology, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, Helsinki FI-00014, Finland (C.W., A.S., J.K.);Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia (A.S.);Max-Planck-Institute for Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (S.A., A.R.F.);Distinguished Scientist Fellowship Program, College of Science, King Saud University, Riyadh, Saudi Arabia (J.K.); andGenomics Research Institute, University of Pretoria, Pretoria, South Africa (Y.V.d.P.).
Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.K., C.W., A.L., P.W., Z.L., P.M., F.A.H., K.V.D.K., R.D.S. Y.V.d.P., F.V.B.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.K., C.W., A.L., P.W., Z.L., P.M., F.A.H., K.V.D.K., R.D.S., Y.V.d.P., F.V.B.);Structural Biology Research Center, VIB, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Structural Biology Brussels Laboratory, Vrije Universiteit Brussel, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Brussels Center for Redox Biology, 1050 Brussels, Belgium (C.W., A.L., J.H., J.M.);Division of Plant Biology, Viikki Plant Science Centre, Department of Biosciences, University of Helsinki, Helsinki FI-00014, Finland (C.W., A.S., J.K.);Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia (A.S.);Max-Planck-Institute for Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (S.A., A.R.F.);Distinguished Scientist Fellowship Program, College of Science, King Saud University, Riyadh, Saudi Arabia (J.K.); andGenomics Research Institute, University of Pretoria, Pretoria, South Africa (Y.V.d.P.)
Plant Physiol. 2016 Jul;171(3):1704-19. doi: 10.1104/pp.16.00359. Epub 2016 May 25.
The genes coding for the core metabolic enzymes of the photorespiratory pathway that allows plants with C3-type photosynthesis to survive in an oxygen-rich atmosphere, have been largely discovered in genetic screens aimed to isolate mutants that are unviable under ambient air. As an exception, glycolate oxidase (GOX) mutants with a photorespiratory phenotype have not been described yet in C3 species. Using Arabidopsis (Arabidopsis thaliana) mutants lacking the peroxisomal CATALASE2 (cat2-2) that display stunted growth and cell death lesions under ambient air, we isolated a second-site loss-of-function mutation in GLYCOLATE OXIDASE1 (GOX1) that attenuated the photorespiratory phenotype of cat2-2 Interestingly, knocking out the nearly identical GOX2 in the cat2-2 background did not affect the photorespiratory phenotype, indicating that GOX1 and GOX2 play distinct metabolic roles. We further investigated their individual functions in single gox1-1 and gox2-1 mutants and revealed that their phenotypes can be modulated by environmental conditions that increase the metabolic flux through the photorespiratory pathway. High light negatively affected the photosynthetic performance and growth of both gox1-1 and gox2-1 mutants, but the negative consequences of severe photorespiration were more pronounced in the absence of GOX1, which was accompanied with lesser ability to process glycolate. Taken together, our results point toward divergent functions of the two photorespiratory GOX isoforms in Arabidopsis and contribute to a better understanding of the photorespiratory pathway.
编码光呼吸途径核心代谢酶的基因能让具有C3型光合作用的植物在富氧大气中存活，这些基因在旨在分离在环境空气中无法存活的突变体的遗传筛选中已被大量发现。作为一个例外，C3物种中尚未描述具有光呼吸表型的乙醇酸氧化酶（GOX）突变体。利用在环境空气中表现出生长受阻和细胞死亡损伤的缺乏过氧化物酶体过氧化氢酶2（cat2-2）的拟南芥突变体，我们在乙醇酸氧化酶1（GOX1）中分离出一个第二位点功能丧失突变，该突变减弱了cat2-2的光呼吸表型。有趣的是，在cat2-2背景中敲除几乎相同的GOX2并不影响光呼吸表型，这表明GOX1和GOX2发挥着不同的代谢作用。我们进一步研究了它们在单个gox1-1和gox2-1突变体中的各自功能，发现它们的表型可以通过增加光呼吸途径代谢通量的环境条件来调节。高光对gox1-1和gox2-1突变体光合作用性能和生长均产生负面影响，但在缺乏GOX1时严重光呼吸的负面后果更明显，这伴随着处理乙醇酸能力的降低。综上所述，我们的结果表明拟南芥中两种光呼吸GOX同工型具有不同功能，有助于更好地理解光呼吸途径。
