Identification and expression analysis of a pathogen-responsive PR-1 gene from Chinese wild Vitis quinquangularis

摘要

In response to pathogen attacks, plant produces a wide range of pathogenesis-related (PR) proteins.?PR-1 genes represent the first identified PR gene family. Most members of PR-1 gene family are not inducible by pathogen attacks.?In this study, we identified a pathogen-responsive PR-1 gene designated as?VqPR-1?(GenBank accession no. JN256202), in a subtractive suppression hybridization (SSH) cDNA-library from?Elsinoe ampelina-inoculated young leaves of Chinese wild?Vitis quinquangularis?clone ‘shang-24’.?VqPR-1?protein contained the requisite signal sequence at the N-terminus, a conserved three-dimensional structure called ‘PR-1 fold’ and a highly conserved six-cysteine motif. Expression level of?VqPR-1?rose rapidly in response to?E. ampelina?infection. The three tested plant defence signaling molecules, salicylic acid (SA), ethephon (Eth) and methyl jasmonate (MeJA) all triggered an induction of?VqPR-1. However, the induction by addition of MeJA was weaker than that induced by SA and Eth. In addition, the response to inoculation withE. ampelina?or treatment with signaling molecules, was sometimes a suppression ofVqPR-1?gene expression. The highest expression of?VqPR-1?was observed in flowers, stems and leaves, while low-level or no obvious transcripts were detected in pericarps and tendrils, respectively.