Associated callus culture technique for in vitro growth of rust fungi

Abstract

Uromyces hobsoni, a rust fungus, infects Jasminum officinale var. grandiflorum. The infection frequently leads to malformations in tissues, mainly leaves and stems. Disease progression can be assessed morphologically by observing the extent of malformation and occurrence of sporulation. The rust fungi, in general, are obligate parasites, and need a living host to complete their life cycle. The difficulty of in vitro propagation of rust fungi has been a major obstacle in their detailed biochemical and molecular analysis. In this paper, we report successful in vitro culture of rust fungi with induction of callus from infected leaves of host plants which contain initial differentiated structures like haustoria and intercellular hyphae. This ‘associated callus culture’ technique has opened new paths for studying host-pathogen interactions of rust fungi.