Fig. 3

Relative expression levels of lactate-producing enzyme genes in K. pneumoniae harboring CRISPRi system. a Relative expression level of pmd gene. L1, L2 and L3 indicate three candidate guide RNAs targeting pmd gene. b Relative expression level of ldhA gene. D1 and D2 indicate two candidate guide RNAs targeting ldhA gene. c Relative expression level of aldA gene. A1 and A2 stand for two candidate guide RNAs targeting aldA gene. d Relative expression level of mgsA gene. M1 and M2 refer to two candidate guide RNAs targeting mgsA gene. Control, without guide RNA. e Relative expression levels of pmd, ldhA, aldA and mgsA genes in Kp(ptac-puuC + placiMALD) at 12 h. Kp(ptac-puuC + plv-dCas9), recombinant K. pneumoniae strain harboring vector ptac-puuC and vector plv-dCas9 where Cas9 was inactive; Kp(ptac-puuC + placiMALD), recombinant K. pneumoniae strain harboring vector ptac-puuC and CRISPRi vector placiMALD simultaneously targeting four lactate-producing enzyme genes pmd, ldhA, aldA and mgsA. *P < 0.05; **P < 0.01