Clones encoding B-1,3-glucanase have been isolated from a Hevea cDNA library prepared from the latex of Hevea brasiliensis using a probe Nicotiana plumbaginifolia cDNA encoding B-1,3-glucanase, gnl. Nucleotide sequence analysis showed that a 1.2 kb Hevea cDNA encoding a basic B-1,3-glucanase showed 68;nucleotide homology to gnl cDNA. Northern blot analysis using the Hevea cDNA as probe detected a mRNA of 1.3 kb which was expressed at higher levels in latex than in leaf. In situ hybridization analysis using petiole sections from Hevea localized the B-1,3-glucanase mRNA to the laticifer cells. Genomic Southern analysis suggested the presence of a low-copy gene family encoding B-1,3-glucanases in H. brasiliensis. Nucleotide sequence data have been submitted to the EMBL/GenBank/DDBJ databases under the accession number U22147.