[Ming-Hsiun Hsieh] No GS2? No problem.

Lee et al., 2022 Plant Physiology

Fig. 1 The Arabidopsis glutamine synthetase2-1 (gln2-1) mutant does not have aberrant phenotypes in the air or high CO2. The glu1-1 mutant impaired in Fd-GOGAT1 has a typical photorespiratory phenotype, small and chlorotic in the air and normal in elevated CO2.

Dr. Ming-Hsiun Hsieh’s laboratory reports that the Arabidopsis glutamine synthetase2 mutants grow normally under air or high CO2 (Fig. 1), challenging the textbook that chloroplastic GS2 is the primary enzyme to assimilate NH4+ derived from photorespiration. The paradigm that the chloroplastic GS/GOGAT cycle is the primary route for NH4+ assimilation is questionable, at least in the reference plant Arabidopsis thaliana. The paper is published in Plant Physiology (DOI: 10.1093/plphys/kiac224). The first author Kim-Teng Lee is a TIGP graduate student, and the coauthor Yi-Hsin Chung is a research assistant in Dr. Hsieh’s lab.