Functional Properties of the MAP Kinase UeKpp2 in .

undergoes an endophytic life cycle in . It induces the stem of its host to swell, forming the edible galls called in China, which are the second most commonly cultivated aquatic vegetable in China. raised for can only reproduce asexually because the infection completely inhibits flowering. The infection and proliferation in the host plants during the formation of edible gall differ from those of conventional pathogens. Previous studies have shown a close relationship between mitogen-activated protein kinase (MAPK) and fungal pathogenesis. In this study, we explored the functional properties of the MAPK UeKpp2. Cross-species complementation assays were carried out, which indicated a functional complementation between the of . and the of . Next, mutants of the UeT14 and the UeT55 sporidia background were generated; these showed an aberrant morphology of budding cells, and attenuated mating and filamentous growth , in the context of normal pathogenicity. Interestingly, we identified another protein kinase, UeUkc1, which acted downstream of UeKpp2 and may participate in the regulation of cell shape. We also found a defect of filamentous growth in mutants that was not related to a defect of the induction of mating-type genes but was directly related to a defect in induction. Overall, our results indicate an important role for UeKpp2 in . that is slightly different from those reported for other smut fungi.