In germlings of U. appendiculatus, a gene designated INF56 is preferentially expressed during development of the infection structures. A comparison of sequences between INF56 genomic DNA and a cDNA revealed several differences, randomly distributed throughout the coding region, which resulted in RFLPs at ASpI, HphI, NruI and ScaI sites. This observation, along with DNA-blot analysis, which revealed multiple copies of INF56 in uredospore genomic DNA, indicated that INF56 represents a multigene family. All copies of INF56 examined contain the same 67-bp intron reported previously (Xuei et al. 1992).
