Population dynamics and transcriptomic responses of Pseudomonas aeruginosa in a complex laboratory microbial community.
Cheng Y, Yam JKH, Cai Z, Ding Y, Zhang LH, Deng Y, Yang L
NPJ Biofilms Microbiomes. 2019. doi: 10.1038/s41522-018-0076-z
COMMENT: In this work, authors establish physiologically reproducible laboratory planktonic and biofilm communities to investigate how Pseudomonas aeruginosa competes with multiple other bacterial species and gains fitness over other species in the mixed-species biofilm communities.
To evaluate the sensitivity of the single molecule detection technique, NanoString nCounter® 16S rRNA array in monitoring population dynamics in a complex laboratory mixed- species microbial community and to investigate the transcriptome of P. aeruginosa competition in this mixed-species community in both planktonic and biofilm modes of growth.
In the 1-day-old planktonic community, the relative abundance of A. baumannii, C. violaceum and E. meningoseptica increased by twofold or more compared with their inocula, whereas the relative abundance of B. subtilis, P. aeruginosa, S. oneidensis, S. aureus, S. gallolyticus and X. campestris decreased to half or less compared with their inocula (...). Interestingly, the microbial population dynamics are quite different in the 5-day-old biofilm community compared with the planktonic community; the relative abundance of K. pneumoniae and P. aeruginosa increased to more than fourfold their initial inputs, whereas most of the other species decreased significantly (...). P. aeruginosa 16 S rRNA constituted ~32.62% of the total 16 S rRNA content, whereas K. pneumoniae constituted ~26.08% of that in 5-day-old biofilms (...) after normalisation factor adjustment.
Among the significantly upregulated genes of P. aeruginosa in the mixed-species biofilm, at least 36 belonged to the T6SS, which accounted for 15% of all the upregulated genes. (...) The ClpV protein is the energy source of T6SS39; the expressions of clpV1, clpV2 and clpV3 belonging to three different sub-type T6SS in P. aeruginosa were all upregulated in the mixed-species biofilm.
(...) the physiology of P. aeruginosa is strongly affected by interspecies interactions, and both biofilm determinants and type VI secretion system contribute to higher P. aeruginosa's fitness over other species in complex biofilm communities.