Molecular cloning and expression analysis of a NPR1 gene from sugarcane

摘要

The NPR1 genes play a pivotal role in systemic acquired resistance in plants. In the present work, a full-length sugarcane NPR1 gene, designated as ScNPR1, was isolated and identified. The full-length cDNA was 2184 bp in length with a 1758 bp open reading frame (ORF), which encoded a 586 amino acids protein with an estimated molecular mass of 65.17 kDa and a calculated isoelectric point (pI) of 5.88. Homology analysis suggested that the ScNPR1 protein was significantly similar to maize ZmNPR1, and shared common features with NPR1 from other plants. Real-time quantitative PCR (RT-qPCR) results indicated that the expression of ScNPR1 was obviously up-regulated after treatment with salicylic acid (SA) and inoculation with the smut disease fungus Ustilago scitaminea. Its expression level was reduced after methyl jasmonate (MeJA) or ethylene treatment. In addition, higher levels of ScNPR1 transcripts were observed in the leaf and sheath tissues of sugarcane cultivars resistant to the smut disease. These results clearly demonstrated that the ScNPR1 gene was likely to be involved in SA-mediated signaling pathway and might play a role in the defense response to sugarcane smut disease.