title: Evolution of Cell Size Homeostasis and Growth Rate Diversity during Initial Surface Colonization of Shewanella oneidensis.
abstract: Cell size control and homeostasis are fundamental features of bacterial metabolism. Recent work suggests that cells add a constant size between birth and division ("adder" model). However, it is not known how cell size homeostasis is influenced by the existence of heterogeneous microenvironments, such as those during biofilm formation. Shewanella oneidensis MR-1 can use diverse energy sources on a range of surfaces via extracellular electron transport (EET), which can impact growth, metabolism, and size diversity. Here, we track bacterial surface communities at single-cell resolution to show that not only do bacterial motility appendages influence the transition from two- to three-dimensional biofilm growth and control postdivisional cell fates, they strongly impact cell size homeostasis. For every generation, we find that the average growth rate for cells that stay on the surface and continue to divide (nondetaching population) and that for cells that detach before their next division (detaching population) are roughly constant. However, the growth rate distribution is narrow for the nondetaching population, but broad for the detaching population in each generation. Interestingly, the appendage deletion mutants (ΔpilA, ΔmshA-D, Δflg) have significantly broader growth rate distributions than that of the wild type for both detaching and nondetaching populations, which suggests that Shewanella appendages are important for sensing and integrating environmental inputs that contribute to size homeostasis. Moreover, our results suggest multiplexing of appendages for sensing and motility functions contributes to cell size dysregulation. These results can potentially provide a framework for generating metabolic diversity in S. oneidensis populations to optimize EET in heterogeneous environments.
authors: Calvin K
authors: CK
authors: Lee
authors: Alexander J
authors: AJ
authors: Kim
authors: Giancarlo S
authors: GS
authors: Santos
authors: Peter Y
authors: PY
authors: Lai
authors: Stella Y
authors: SY
authors: Lee
authors: David F
authors: DF
authors: Qiao
authors: Jaime De
authors: J
authors: Anda
authors: Thomas D
authors: TD
authors: Young
authors: Yujie
authors: Y
authors: Chen
authors: Department of Earth Sciences & Biological Sciences, University of Southern California , Los Angeles, California 90089, United States.
authors: Annette R
authors: AR
authors: Rowe
authors: Department of Earth Sciences & Biological Sciences, University of Southern California , Los Angeles, California 90089, United States.
authors: Kenneth H
authors: KH
authors: Nealson
authors: Paul S
authors: PS
authors: Weiss
authors: Gerard C L
authors: GCL
authors: Wong
keywords: Shewanella oneidensis; bacteria biofilm communities; bacteria microscopy; bacterial appendages; cell size homeostasis; single-cell tracking