A gene coding for a basic pathogenesis-related (PR-like) protein from Zea mays. Molecular cloning and induction by a...

Pathogenesis-related proteins (PRs) are plant proteins produced in leaves in response to infection by pathogens including viruses, viroids, fungi and bacteria. Information on the presence and/or expression of PRs in monocotyledonous plants is scare. Here we report the identification of cDNA and genomic clones coding for a basic form of a protein from germinating maize seeds having a high homology with the group of PR-1 from tobacco. A cDNA library enriched in aleurone-specific sequences was prepared from maize seeds two days after germination. One clone was found to contain an open reading frame encoding a protein homologous to PR proteins from tomato (p14) and tobacco (PR-1 group). Sequence analysis of the corresponding genomic clone revealed that it was encoded by a single exon. Besides, DNA blot hybridization indicates that this PR-like protein is encoded by a single-copy gene in maize. The accumulation of its mRNA increases after rehydration of desiccated seeds. Furthermore, a relationship was found between its expression and infection by a natural pathogen of maize, the fungus Fusarium moniliforme. The possible role of this protein as a response mechanism following fungal infection in cereal seeds is discussed.