Myxococcus xanthus cellular structures during early development

Aggregation underlies collective dynamics of a diversity of organisms,
enabling the formation of complex structures and emergent behaviours in
interaction with the environment. Cellular aggregation constitutes one of
the routes to collective motility and multicellular development.
Myxococcus xanthus, a social bacterium, is a valuable model for studying
the aggregative way to multicellularity, a major transition in the
evolutionary history of life. While the collective developmental behaviour
of M. xanthus has been largely studied in  high cellular
densities, there is a lack of understanding at low density conditions that
can be ecologically relevant. In this work, we study the early stages of
emergent collective behaviour of M. xanthus under nutrient-poor and low
density conditions, uncovering the formation of diverse cellular
structures with different shapes and sizes, ranging from individual cells
to networks comprising thousands of cells. We study their motility
patterns and their prevalence along development, and discuss their
cross-scale role on the population’s exploratory dynamics. This work
contributes to understanding key, yet largely understudied, aspects in the
early stages of multicellular development in myxobacteria, shedding light
on the dynamics underlying aggregative processes in this and other taxa
and study systems.