The present invention relates to plant proteins produced by a plant's epidermal layer that contribute to the innate pest/disease resistance of the plant (“phylloplanins”), compositions comprising the phylloplanins and methods of using them. In particular the methods relate to inhibiting or preventing microbial, e.g., fungal or bacterial, growth on a subject, organism or surface by administering a phylloplanin. The invention also relates to transformed host cells that produce phylloplanins, and to transgenic plants producing phylloplanins conferring increased resistance to microbial infections/growth.