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Elucidating the functions of methyl-accepting chemotaxis (mcp) proteins of Dickeya dianthicola

Afnan Shazwan Nasaruddin: Colorado State University

<div>Potato is the fourth most consumed food globally, and the most important non-grain crop worldwide. In the U.S., potato has an annual approximate of $4 billion farm gate value. Every year, soft rot disease of potato caused by <em>Dickeya </em>spp. and <em>Pectobacterium </em>spp. contributes to at least 1% crop losses, which is about $400 million. In 2015, an aggressive species of <em>Dickeya,</em> identified as <em>Dickeya dianthicola,</em> created a new threat to the U.S. potato industry. <em>D. dianthicola </em>was reported in 10 states and its spread had been confirmed in 23 states by 2016. A genomic comparison of 307 Enterobacteriaceae showed that <em>Pectobacterium </em>and<em> Dickeya </em>genomes are enriched in methyl-accepting chemotaxis proteins (MCP) and ATP-binding cassette (ABC) transporters compared to other closely related animal pathogens in this family. Some of these MCP and ABC transporters may detect and transport plant metabolites that affect bacterial growth. A phenotype array identified compounds metabolized by soft rot Enterobacteriaceae and some of the same molecules were identified in the potato stem and stolon metabolomes. <em>D. dianthicola </em>ME23 showed chemotaxis towards potato tuber extract. To determine which compounds MCPs may sense, we transformed 42 <em>mcp </em>genes from <em>D. dianthicola </em>ME23 into <em>Escherichia coli </em>UU1250 and assayed transformants via qualitative plate-based chemotaxis using various carbon sources, amino acids, and other metabolites found in potato.</div>