A review of the most recent developments in so-called “Soil-on-a-Chip” microfluidic technology for environmental organismal studies, including bacteria, nematodes, fungi and plants, as well as inter-organismal interactions.

A chiral tris(urea) organogelator gels dmso–water and methanol–water mixtures at low weight percent. The formation of the helical gel fibres is partially inhibited by addition of chloride, which is bound by the gelator, resulting in fully crystalline material characterised by X-ray crystallography

Summary: Roots grow in highly dynamic and heterogeneous environments. Biological activity as well as uneven nutrient availability or localized stress factors result in diverse microenvironments. Plants adapt their root morphology in response to changing environmental conditions, yet it remains largely unknown to what extent developmental adaptations are based on systemic or cell‐autonomous responses. We present the dual‐flow‐RootChip, a microfluidic platform for asymmetric perfusion of Arabidopsis roots to investigate root–environment interactions under simulated environmental heterogeneity. Applications range from investigating physiology, root hair development and calcium signalling upon selective exposure to environmental stresses to tracing molecular uptake, performing selective drug treatments and localized inoculations with microbes. Using the dual‐flow‐RootChip, we revealed cell‐autonomous adaption of root hair development under asymmetric phosphate (Pi) perfusion, with unexpected repression in root hair growth on the side exposed to low Pi and rapid tip‐growth upregulation when Pi concentrations increased. The asymmetric root environment further resulted in an asymmetric gene expression of RSL4, a key transcriptional regulator of root hair growth. Our findings demonstrate that roots possess the capability to locally adapt to heterogeneous conditions in their environment at the physiological and transcriptional levels. Being able to generate asymmetric microenvironments for roots will help further elucidate decision‐making processes in root–environment interactions.

The new microfluidic platforms enable dynamic interactions between filamentous fungi and bacteria to be monitored at the single cell level.