Enhancing phosphate-solubilising microbial communities through artificial selection.

Microbial communities, acting as key drivers of ecosystem processes, harbour immense potential for sustainable agriculture practices. Phosphate-solubilising microorganisms, for example, can partially replace conventional phosphate fertilisers, which rely on finite resources. However, understanding the mechanisms and engineering efficient communities poses a significant challenge. In this study, we employ two artificial selection methods, environmental perturbation, and propagation, to construct phosphate-solubilising microbial communities. To assess trait transferability, we investigate the community performance in different media and a hydroponic system with Chrysanthemum indicum. Our findings reveal a distinct subset of phosphate-solubilising bacteria primarily dominated by Klebsiella and Enterobacterales. The propagated communities consistently demonstrate elevated levels of phosphate solubilisation, surpassing the starting soil community by 24.2% in activity. The increased activity of propagated communities remains consistent upon introduction into the hydroponic system. This study shows the efficacy of community-level artificial selection, particularly through propagation, as a tool for successfully modifying microbial communities to enhance phosphate solubilisation.

A committed postselection precursor to natural TCRαß+ intraepithelial lymphocytes.

The intestine is a major immune organ with several specialized lymphoid structures and immune cells. Among these are thymus-derived natural intraepithelial lymphocytes (IELs) that lack expression of the classical co-receptors CD4 or CD8αß (double negative (DN)). Natural IELs are both αß+ and γδ+ T cells that play important roles in the maintenance of the epithelial barrier at steady state and during inflammation. The transcription factor T-bet is essential for the peripheral development of natural IELs, but its role during thymic development has remained less clear. Here we show that a T-bet gradient in DN TCRαß+NK1.1- thymocytes (IEL precursors (IELPs)) determines IEL fate in natural TCRαß+ IELs. Employing T-bet ZsGreen reporter mice in in vitro cultures and in vivo transfer experiments, we demonstrate that with increasing expression of T-bet, DN TCRαß+NK1.1- thymocytes are gradually restricted to a DN IEL fate. Furthermore, we show that the natural TCRαß+ IELs seed the intestine within the first month of life. This in turn is preceded by the appearance of T-bet- and T-bet+ IELPs that egress from the thymus in a sphingosine-1-phosphate (S1P)-dependent manner. In summary, the use of T-bet reporter mice has enabled us to identify and refine an immediate and clearly committed postselection precursor of natural TCRαß+ IELs.