What additional plant hosts are typically affected by corn smut?

Corn smut, caused by the fungus Ustilago maydis, primarily targets corn but can also affect other related plants, particularly those in the grass family. This includes various grasses and cereals, where it can cause similar galls and deformities as seen in corn. The fact that these additional hosts are in the same taxonomic family as corn enhances the likelihood of infection, as the pathogen has evolved to exploit specific biochemical interactions and anatomical structures common to these plants.

The other options mention plants like potatoes, tomatoes, legumes, and fruit trees, none of which are particularly susceptible to Ustilago maydis. These plants belong to different families and do not provide a conducive environment or the necessary biological compatibility for the fungus to infect and establish itself effectively. Thus, the specific relationship between corn and other grasses or cereals makes the inclusion of these additional hosts more relevant in the context of corn smut's life cycle and host range.