Research Interest

Glutamine metabolism and signaling in plants

Glutamine (Gln), the first organic nitrogen (N) compound produced during primary N assimilation, is increasingly recognized as a signaling molecule in plants. We recently discovered that Gln induces defense gene expression and promotes root hair elongation in Arabidopsis. Based on these findings, we proposed a working model in which Gln, in addition to its established role in N metabolism, functions as a signaling molecule that triggers plant defense responses and root hair elongation (Fig. 1). Our research aims to elucidate the molecular mechanisms underlying Gln signaling in plants.

Fig. 1. A hypothetical model of exogenous Gln–induced defense responses and root hair elongation.

Use of Arabidopsis and rice mutants to study Gln and Glu signaling

Glutamate (Glu), another amino acid produced during N assimilation, is widely recognized as a signaling molecule in plants. To determine whether Gln and Glu signaling share common or distinct molecular mechanisms in regulating plant growth, defense gene expression, and root hair elongation, we employ genetic approaches to identify Arabidopsis mutants defective in these responses (Fig. 2). Identifying the underlying genes will provide insights into the molecular mechanisms by which Gln and Glu regulate growth, defense, and root hair development in Arabidopsis.

Fig. 2. Representative images of Arabidopsis mutants grown with glutamine (Gln) or glutamate (Glu) as the sole nitrogen source.

      Rice is the most important staple food crop in Taiwan. In addition to Arabidopsis, we use rice as a model system to investigate Gln signaling. We previously identified several transcription factor genes that are rapidly induced by Gln in rice seedling roots. To investigate the functions of these Gln-responsive genes (NRGs), we used CRISPR/Cas9 technology to generate a collection of rice mutants (Fig. 3). These CRISPR mutants provide a valuable foundation for elucidating the molecular mechanisms underlying Gln signaling in rice.

Fig. 3. Molecular lesions and representative images of OsNRG1 CRISPR/Cas9 mutants.