Abstract
INTRODUCTION: The ANGUSTIFOLIA3 (AN3) gene encodes a transcriptional co-activator for cell proliferation in Arabidopsis thaliana leaves. We previously showed that Physcomitrium patens AN3 orthologs promote gametophore shoot formation through arginine metabolism. OBJECTIVES: We analyzed the role of AN3 in Arabidopsis thaliana to understand how seedling growth is regulated by metabolic and physiological modulations. METHODS: We first explored amino acids that affect the seedling growth of an3 mutants. Transcriptome and metabolome analyses were conducted to elucidate the metabolic and physiological roles of AN3 during seedling growth. Lastly, we examined the distribution of reactive oxygen species to corroborate our omics-based findings. RESULTS: Our results indicated that an3 mutants were unable to establish seedlings when grown with leucine, but not arginine. Multi-omics analyses suggested that an3 mutants exhibit a hypoxia-like response. Abnormal oxidative status was confirmed by detecting an altered distribution of reactive oxygen species in the roots of an3 mutants. CONCLUSION: AN3 helps maintain the leucine metabolism and oxidative balance during seedling growth in Arabidopsis thaliana. Future research is necessary to explore the interaction between these processes.