Fig. 7. Capsule genes cpsC and cpsD are expendable in agarose droplets.

a The volcano plot shows genome-wide fitness changes from a dTn-Seq experiment between droplet growth in glucose and droplet growth in 1% agarose. Significant genes are highlighted in color, which represent each gene’s functional category shown in the “Gene Category” figure key. b Wild-type (orange), ΔcpsC (green), and ΔcpsD (blue) were cultured in either liquid batch culture or agarose droplets. In each condition, the relative growth expansion was determined for each strain by counting the number of cells in the population at the beginning of the experiment and at the end after 5 h of culture. Growth expansion of the mutants are relative to the expansion of the wt strain within each growth environment (each experiment was performed at least four times). Growth is improved when the mutants are embedded in agarose (Kruskal–Wallis with Dunn’s test for multiple testing; ns = not significant, ** < 0.005, error bars are standard error of the mean). c Agarose droplets in oil with encapsulated S. pneumoniae, which have developed into compact microcolonies. ΔcpsC and ΔcpsD mutants develop similarly sized microcolonies compared to WT after 5 h. White arrows indicate microcolonies. Source data are available in the Source Data file.