Glycolate oxidase modulates photosynthetic activity and reactive oxygen species metabolism in Arabidopsis thaliana under salt stress

1 página - Poster presentado en Iberian Plant Biology 2023. XVIII Portuguese-Spanish Congress on Plant Biology and the XXV Meeting of the Spanish Society of Plant Biology. 9-12 Julio 2023, Braga, Portugal.Salt stress is one of the biggest environmental factors impacting plant growth and productivity in many parts of the world, particularly in irrigated lands of arid and semi‐arid regions. The involvement of glycolate oxidase (GOX), an enzyme that catalyzes the conversion of glycolate into glyoxylate during photorespiration with concomitant production of H₂O₂, in the regulation of photosynthesis and reactive oxygen species (ROS) metabolism was investigated in salt‐challenged Arabidopsis wild type and two gox Arabidopsis mutants (gox1 and gox2). Plants were grown under hydroponic conditions supplemented or not with 100 mM NaCl for 24 h. Under control conditions, pigments contents (chla, chlb, total chlorophyll) were higher in WT than gox mutants. However, a different behavior was observed following NaCl treatment. The same trend of pigment content was registered for gas exchange parameters. Under control conditions, as expected, leaf GOX activity was reduced in gox mutants compared to WT, while NaCl increased GOX activity only in gox mutants. Leaf H₂O₂ content was reduced in gox mutants compared to WT under control and stress conditions. NaCl‐induced oxidative stress, noticed by oncrease of malondialdehyde content, was observed only in WT and gox1 mutant. Modulation of catalase, guaiacol peroxidase, and glutathione reductase activitives in leaves were also registered in all genotypes and depending on the treatment. As a whole, data show the crucial role of GOX in regulating both photosynthetic activity and ROS metabolism under salinity conditions.This work was supported by I‐COOP grant (COOPA20471) from the CSIC, Spain and PID2021‐122280NB‐I00 and RED2018‐102407‐T from the Ministry of Science, Innovation and Universities and the European Regional Development Fund co‐funding (MCIU/AEI/ERDF