beta-1,3-glucanases, one of the well known families of pathogenesis-related (PR) proteins in responding to pathogen infection or some environmental stresses, are hydrolytic enzymes abundant in plants. The plant beta-1,3-glucanases are considered to have a broad range of biological functions in the normal physiological process as well as in the defence response against pathogens. Some plant beta-1,3-glucanases were studied in detail as antifungal proteins in vivo or in vitro. To investigate the beta-1,3-glucanase genes involved in self-defence during fruit development, a novel gene PpGlu was isolated from the fruit of Pyrus pyrifolia Nakai cv Huobali, which is a kind of local sand pear of China with high resistance to biotic and abiotic stresses. The putative protein sequence of PpGlu was highly homologous with beta-1,3-glucanases from other plant species. Bioinformatics analyses indicated that the catalytic and other conserved amino acid residues occupied highly conserved positions in the primary structure of the putative protein PpGlu and other plant beta-1,3-glucanases. Moreover, PpGlu had rather conserved main-chain conformation and the folding patterns of plant beta-1,3-glucanases. The transcripts of PpGlu was dramatically induced in pericarps of 'Huobali' fruits by removing the bags for 2 days, but rapidly declined after the fruits were debagged for 1 week. Furthermore, a constitutive plant expression vector of PpGlu was constructed and transferred into tobacco (Nicotiana tabacum L. cv Xanthi) to verify the function of PpGlu. The PpGlu gene was successfully integrated into the genome of the transgenic tobacco lines and expressed as expect in the transformants by Southern blotting and quantitative reverse transcription-polymerase chain reaction (QRT-PCR) analyses. The antifungal activity of PpGlu was detected in vitro plates, and the crude protein extract of transgenic tobacco lines inhibited the hyphal growth of the following three fungi, Phomopsis sp., Alternaria sp. and Fusarium sp. at different degrees.