Characteristics of the sigK Deletion Mutant from Bacillus thuringiensis var. israelensis Strain Bt-59

Characterization of CwlC, an autolysin, and its role in mother cell lysis of Bacillus thuringiensis subsp. israelensis

“…Since cell lysis in Bt‐59 is not completely blocked in the sigK knockout strain (Xu et al . 2020), and since cwlE is the only hydrolase gene with high expression in this strain, it seemed reasonable to hypothesize that CwlE is a new and critical autolysin leading to mother cells lysis in Bti .…”

“…In our previous study, the complete genome of Bt‐59 was sequenced and was found to consist of one chromosome (CP039721) and five plasmids (CP039722‐CP039726) (Xu et al . 2020). A total of 12 putative cell wall hydrolases were found according to the gene annotation information (Table ).…”

“…Our results confirm that although cwlC from both Bti and Btk is regulated by SigK, the deletion of sigK to inhibit the expression of cwlC could not completely block mother cell lysis in Bti (Xu et al . 2020).…”

“…pipiens in the early fourth instar were collected for bioassay in each treatment (Xu et al . 2020). The experiment was performed with three replicates per concentration at 28°C in a biochemical incubator for 24 h, and distilled water was used as control.…”

“…However, the deletion of sigK just delayed and not completely blocked the lysis of mother cells (Xu et al . 2020). We have though observed that a sigK knockout of a variant of Bti lacking the toxin‐encoding plasmid is protected from cell lysis (unpublished data).…”