Root-sleeve, bacterial microbiome

We studied the effect of host-related factors, i.e. plant compartment, on the composition of the root-associated microbiome. We showed that the microbiome composition in the root-sleeve (RS), a peculiar root structure that can be moved along the root in 2 desert grass species, was significantly different from that in the bulk soil, RH and EC, albeit it was most similar to that in EC. Actinobacteria and Proteobacteria ASVs were enriched with the highest abundance in both RS or/and EC compartments. Further, we studied the developmental and cellular processes underlying the formation of the RS and we showed that the RS contains outer cortical cells, epidermis and tightly adhered sandy layer at the root surface. We suggested that the formation of RS was an adaptation of arid tolerant grasses by integrating, from outside to inside, rhizosheath formation, formation of lacunae in the inner cortex and endodermal cell wall modification and hydrolysis.