Molecular cloning and characterization of pathogenesis-related protein 5 in <i>Zea mays</i> and its antifungal activity against <i>Rhizoctonia solani</i>

Abstract

We described the cloning and characterization of pathogenesis-related protein 5 gene in maize, named ZmPR5 (GenBank Accession Number: HM230665). Molecular and bioinformatic analyses of ZmPR5 revealed an open reading frame (ORF) of 525 bp, encoding a protein of 175 amino acids (aa) and a deduced molecular mass of 17.5 KDa. Homology analysis of the Zea mays L. deduced amino acid sequence, indicated homology between 40 and 74% with Oryza sativa, Hordeum vulgare, and Triticum aestivum, among others. Real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the expression of ZmPR5 is constantly higher in the maize resistant inbred line R15 compared with that in the susceptible inbred line 478. Moreover, the ZmPR5 gene was up-regulated after it was challenged by Rhizoctonia solani. We subsequently purified the recombinant protein and analyzed its antimicrobial activities in vitro. The results obtained show that the recombinant protein inhibited hyphal growth of R. solani. This study suggests that the expression of ZmPR5 is closely related to maize sheath blight resistance caused by R. solani. Further, the antifungal activity of ZmPR5 showed that ZmPR5 plays an important role in the disease resistance response.

Key words: Maize, ZmPR5, banded leaf and sheath blight, pathogenesis-related protein, Rhizoctonia solani.