Identical homologs of the Galanthus nivalis agglutinin in Zea mays and Fusarium verticillioides

The structural domain corresponding to the Galanthus nivalis agglutinin (GNA) is a mannose-binding motif that was originally discovered in plants but according to recent data also occurs in other eukaryotes and prokaryotes. Transcriptome analyses revealed that Fusarium verticillioides expresses a protein (FvGLLc1) identical to a recently identified cytoplasmic/nuclear GNA-like lectin from maize (ZmGLLc). The FvGLLc1 and ZmGLLc gene sequences are nearly identical in the coding region as well as in the intron and the 5 and 3 prime untranslated regions. However, whereas the Fusarium genome contains only a single gene with an intron, both an intronless and an intron containing lectin gene can be amplified from maize DNA. Southern blot analysis confirmed the presence of this cytoplasmic GNA-like gene in the maize and rice genome. A comparative analysis of the products amplified by different PCRs using genomic DNA from Fusarium species and maize DNA samples from sterile as well as contaminated plant material strongly indicated that the GNA-like sequence found in maize grown under sterile conditions is not derived from a contaminating Fusarium species. Furthermore, using a PCR-based approach it could be demonstrated that this particular type of lectin occurs also in other plants from distant taxa and is markedly conserved.