Small heat shock proteins (HSP12, HSP20 and HSP30) play a role in Ustilago maydis pathogenesis.

Small heat shock proteins (HSP) have multiple functions within a cell. These functions primarily include regulation of growth and survival in response to different stresses. However in some cases small HSPs have been shown to play crucial roles in microbial pathogenesis. Ustilago maydis genome also codes for a number of small HSPs. In the present study we elucidate the role of U. maydis small HSPs in the pathogenicity as well as general stress response of the fungus. Through quantitative real time PCR analysis the expression levels of small HSP genes in comparison with other HSPs were assessed both during infection of the host plant Zea mays and when the pathogen was subjected to an abiotic stress such as oxidative stress. This study revealed that contrary to other HSPs, small HSPs showed an increased level of differential expression under both the tested conditions, indicating a possible role of small HSPs in the pathogenicity and stress response of U. maydis This has been further confirmed by generation of deletion and complementation strains of three putative small HSPs.