Table 1. Strains and plasmids used in this study.

Strain or plasmid	Relevant properties	Source
Bacterial strains
C. botulinum ATCC 3502	Wild type parental strain	ATCC1
C. botulinum ATCC 3502 cbo0097::intron 124|125AS	Insertional disruption of cbo0097 at base 124 in antisense orientation, erm	This study
C. botulinum ATCC 3502 cbo0097::intron 84|85S	Insertional disruption of cbo0097 at base 84 in sense orientation, erm	This study
C. botulinum ATCC 3502 cbo0477::intron 152|153AS	Insertional disruption of cbo0477 at base 152 in antisense orientation, erm	This study
C. botulinum ATCC 3502 cbo0477::intron 111|112S	Insertional disruption of cbo0477 at base 111 in sense orientation, erm	This study
C. botulinum ATCC 3502 cbo0558A::intron 121|122AS	Insertional disruption of cbo0558A at base 121 in antisense orientation, erm	This study
C. botulinum ATCC 3502 cbo0558A::intron 114|115S	Insertional disruption of cbo0558A at base 114 in sense orientation, erm	This study
Plasmids
pMTL007C-E2	ClosTron plasmid, catP, L1.LtrB intron with ermB RAM, constitutive intron expression under fdx promoter	University of Nottingham [77]
pMTL007C-E2:: cbo0097-124|125AS	pMTL007C-E2 with L1.LtrB retargeted to base 124 of cbo0097 in antisense orientation	This study
pMTL007C-E2:: cbo0097-84|85S	pMTL007C-E2 with L1.LtrB retargeted to base 84 of cbo0097 in antisense orientation	This study
pMTL007C-E2:: cbo0477-152|153AS	pMTL007C-E2 with L1.LtrB retargeted to base 152 of cbo0477 in sense orientation	This study
pMTL007C-E2:: cbo0477- 111|112S	pMTL007C-E2 with L1.LtrB retargeted to base 111 of cbo0477 in antisense orientation	This study
pMTL007C-E2:: cbo0558A-121|122AS	pMTL007C-E2 with L1.LtrB retargeted to base 121 of cbo0558A in sense orientation	This study
pMTL007C-E2:: cbo0558A- 114|115S	pMTL007C-E2 with L1.LtrB retargeted to base 114 of cbo0558A in antisense orientation	This study

¹ATCC, American Type Culture Collection.