Isolation and identification of a salt-inducible gene encoding a putative NAC-binding transcription factor from Poa pratensis

NAC proteins play essential role in regulating various metabolic processes including molecular signal transduction in plants. A new NAC-binding protein gene PpNAC encoding an NAC-type transcription factor was isolated by RACE-PCR from Poa pratensis seedlings. Its ORF cDNA was 837bp long, from which a protein with 278 amino acid residues was deduced with a predicted molecular mass of 31.43kDa and a pI of 5.30. Clustering analysis showed that PpNAC is a nuclear protein, which belongs to OsNAC3 subfamily of the NAC protein family. PpNAC exhibited the highest identity to SNAC1, and the lowest identity to NAC1. The expression of PpNAC was promoted significantly by 4°C, 37°C, 250mM NaCl, 100μM ABA and 10mM SA, and inhibited by 20% PEG, 100μM MeJA and 100μM ET. PpNAC seems to participates in regulatory processes involved in defense responses and stress resistance in Poa pratensis.