OsNAC2 protein localizes in the nucleus (evidence: experimental from OsNAC2?mGFP fusion protein) and acts as a negative regulator of drought and salinity tolerance. It is expressed in all tissues representing vegetative and reproductive stages of rice, including the embryo, the coleoptile, the radicle, the pulvinus, ligules, leaves, root, shoot, panicles, the palea and lemma, the anther, panicles, and the internode of the peduncle. Its high expression is observed in young leaves, root meristems, florescence meristem, young spikelets, sheath, the peduncle, and the inflorescence and low expression is observed in the flag leaf and internodes (Chen et al., 2015, Mao et al., 2007). It is strongly induced by ABA, drought, and high salt. OsNAC2 overexpression lines show lower resistance to high salt and drought conditions. Likewise, RNAi plants that inhibit OsNAC2 expression show enhanced tolerance to high salinity and drought stress at both the vegetative and flowering stages (Shen et al., 2017). The OsNAC2 overexpression lines show down-regulation of ABA-dependent stress-related genes, including several genes involved in the ABA and GA biosynthesis and signaling. OsNAC2 promotes programmed cell death accompanied by the loss of plasma membrane integrity, nuclear DNA fragmentation, and changes to caspase-like activity. In OsNAC2-knockdown transgenic rice plants, cell death was markedly decreased in response to severe salt stress (Mao et al., 2018).
