Nucleoredoxin2 (NRX2) Promotes Jasmonate-Mediated Trichome Formation in Arabidopsis

Thioredoxin (Trx) proteins are essential for the maintenance of cellular redox balance through thiol/disulfide exchange modification. In Arabidopsis, the Trx superfamily consists of multiple protein isotypes distributed in most cellular compartments. Although the functions of chloroplastic and cytosolic Trxs have been investigated in plants, the physiological role of nuclear Trx proteins remains elusive. Nucleoredoxin (NRX) is a nuclear Trx first identified in eukaryotic organisms. Arabidopsis possesses two NRX genes (AtNRX1 and AtNRX2), and the function of AtNRX2 has not been elucidated to date. In this study, we characterized the function of AtNRX2 using the atnrx2 knockout mutant, based on its comparison with the atnrx1 mutant. In atnrx2 knockout mutant plants, trichome number was significantly reduced compared with the wild type (WT; Col-0) and the atnrx1 mutant. In response to JA induction of trichome, trichome formation was markedly diminished in the atnrx2 mutant. In addition, expression levels of genes involved in trichome formation were reduced in the atnrx2 mutant compared with the WT and atnrx1 mutant. Overall, our results suggest that AtNRX2 plays a physiological role in JA-mediated trichome formation in Arabidopsis.