Involvement of the PKA and MAPK signal transduction pathways in sclerotial morphogenesis in Sclerotinia sclerotiorum

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The long-term goals of our research are to understand the regulation of sclerotial development and pathogenicity in S. sclerotiorum. The focus in this project is on the elucidation of the signaling events and environmental cues involved in the regulation of these processes, utilizing and continuously developing tools our research groups have established and/or adapted for analysis of S. sclerotiorum. Our stated specific objectives were to: 1. Follow activities and function of S. sclerotiorumPKA. 2. Identify and functionally evaluate effectors of the S. sclerotiorumERK-likeMAPK signaling pathway. 3. Perform structural and functional analysis of genes whose expression is altered under conditions affecting either PKA and/or MAPK. As can be seen below, we have not only met most of the listed goals, but have also expanded our research. We have been working both together and in parallel in order to advance our goals. We have jointly shown how an ERK-likeMAPK is required sclerotia formation. We have analyzed, in parallel, the involvement of PKA in sclerotiogenesis and, interestingly, have reached some overlapping results but each group has provided a slightly different interpretation to the picture obtained. It will be interesting to see how this aspect of the analysis progresses, as we jointly tackle the yet unresloved issues. We have also made progress on the analysis of ser/thr phosphatases (specifically – calcineurin, which has been reported to interact with PKA) and PP2A in S. sclerotiorum as well as the S. sclerotiorum rasgene, which we have cloned and shown induces SMK1, the ERK-like kinase responsible for sclerotia formation. In addition to the time and efforts invested towards reaching the specific goals mentioned, both PIs are actively involved in a major international effort to sequence and annotate the entire S. sclerotiorum genome. Though time consuming (and perhaps requiring divergence of some time and resources from the original workplan), we have given this topic a very high priority to this effort as the long term implications of the success of this venture are enormous.