. Author manuscript; available in PMC: 2023 Feb 1.

Published in final edited form as: Curr Opin Microbiol. 2021 Nov 10;65:81–86. doi: 10.1016/j.mib.2021.10.017

Table 1.

Regulatory role of the Agr system in Clostridia

Clostridia	Discovered Roles of the Quorum Signaling Systems in Clostridia
C. difficile Agr1	Regulate toxin production, sporulation, and motility
C. difficile Agr2	Positive regulator of TcdA production and flagella formation
C. difficile Agr3	Unknown
C. acetobutylicum Agr	Positively regulates sporulation
C. perfringens Agr	Positive regulator of PFO, PLC, ColA, CPA, CPB, CPE, ETX, NETB toxins, and of sporulation.
C. botulinum Agr1	Positively regulates sporulation
C. botulinum Agr2	Positively regulates sporulation