Photorhabdus and Xenorhabdus species have mutualistic associations with nematodes and an entomopathogenic stage^1,2 in their life cycles. In both stages, numerous specialized metabolites are produced that have roles in symbiosis and virulence^3,4. Although regulators have been implicated in the regulation of these specialized metabolites^3,4, how small regulatory RNAs (sRNAs) are involved in this process is not clear. Here, we show that the Hfq-dependent sRNA, ArcZ, is required for specialized metabolite production in Photorhabdus and Xenorhabdus. We discovered that ArcZ directly base-pairs with the mRNA encoding HexA, which represses the expression of specialized metabolite gene clusters. In addition to specialized metabolite genes, we show that the ArcZ regulon affects approximately 15% of all transcripts in Photorhabdus and Xenorhabdus. Thus, the ArcZ sRNA is crucial for specialized metabolite production in Photorhabdus and Xenorhabdus species and could become a useful tool for metabolic engineering and identification of commercially relevant natural products.

Photorhabdus和Xenorhabdus物种在其生命周期中与线虫和昆虫致病阶段^1,2具有共生关系。在这两个阶段，都会产生许多在共生和毒力^{3,4 中}发挥作用的专门代谢物。尽管监管者参与了这些特殊代谢物的调节^3,4，但尚不清楚小调节 RNA (sRNA) 是如何参与这一过程的。在这里，我们表明 Hfq 依赖性 sRNA ArcZ 是Photorhabdus和Xenorhabdus 中专门代谢物生产所必需的. 我们发现 ArcZ 直接与编码 HexA 的 mRNA 碱基配对，后者抑制了特化代谢物基因簇的表达。除了专门的代谢物基因外，我们还表明 ArcZ 调节子影响Photorhabdus和Xenorhabdus中所有转录本的大约 15% 。因此，ArcZ sRNA 对于Photorhabdus和Xenorhabdus物种的专门代谢物生产至关重要，并且可能成为代谢工程和商业相关天然产物鉴定的有用工具。