Molecular Cloning and Functional Analysis of the Homolog in Kiwifruit ().

Kiwifruit bacterial canker, caused by the bacterial pathogen pv. (Psa), is a destructive disease in the kiwifruit industry globally. Consequently, understanding the mechanism of defense against pathogens in kiwifruit could facilitate the development of effective novel protection strategies. The () is a critical component of the salicylic acid (SA)-dependent signaling pathway. Here, a novel kiwifruit -like gene, designated , was isolated by using PCR and rapid amplification of cDNA ends techniques. The full-length cDNA consisted of 1952 base pairs with a 1,746-bp open-reading frame encoding a 582 amino acid protein. Homology analysis showed that the AeNPR1a protein is significantly similar to the VvNPR1 of grape. A 2.0 Kb 5'-flanking region of was isolated, and sequence identification revealed the presence of several putative cis-regulatory elements, including basic elements, defense and stress response elements, and binding sites for WRKY transcription factors. Real-time quantitative PCR results demonstrated that had different expression patterns in various tissues, and its transcription could be induced by phytohormone treatment and Psa inoculation. The yeast two-hybrid assay revealed that AeNPR1a interacts with AeTGA2. Constitutive expression of induced the expression of pathogenesis-related gene in transgenic tobacco plants and enhanced tolerance to bacterial pathogens. In addition, expression could restore basal resistance to pv. DC3000 (Pst) in mutant. Our data suggest that gene is likely to play a pivotal role in defense responses in kiwifruit.