Conservation of beneficial microbes between the rhizosphere and the cyanosphere

Abstract

Summary Biocrusts are phototroph‐driven communities inhabiting arid soil surfaces. Like plants, most photoautotrophs (largely cyanobacteria) in biocrusts are thought to exchange fixed carbon for essential nutrients like nitrogen with cyanosphere bacteria. Here, we aim to compare beneficial interactions in rhizosphere and cyanosphere environments, including finding growth‐promoting strains for hosts from both environments. To examine this, we performed a retrospective analysis of 16S rRNA gene sequencing datasets, host–microbe co‐culture experiments between biocrust communities/biocrust isolates and a model grass (Brachypodium distachyon) or a dominant biocrust cyanobacterium (Microcoleus vaginatus), and metabolomic analysis. All 18 microbial phyla in the cyanosphere were also present in the rhizosphere, with additional 17 phyla uniquely found in the rhizosphere. The biocrust microbes promoted the growth of the model grass, and three biocrust isolates (Bosea sp._L1B56, Pseudarthrobacter sp._L1D14 and Pseudarthrobacter picheli_L1D33) significantly promoted the growth of both hosts. Moreover, pantothenic acid was produced by Pseudarthrobacter sp._L1D14 when grown on B. distachyon exudates, and supplementation of plant growth medium with this metabolite increased B. distachyon biomass by over 60%. These findings suggest that cyanobacteria and other diverse photoautotrophic hosts can be a source for new plant growth‐promoting microbes and metabolites.

Phylometagenomics of cycad coralloid roots reveals shared symbiotic signals

“…Nostocales, Hypomicrobiales, Caulobacterales, Sphingomonadales, Burkholderiales, Xanthomonadales and Sphingobacterales , can be found in cycads and other symbiotic systems [21, 35–38] (). This degree of universal conservation implies selection [84] that might be based in supporting functional roles [37, 82].…”

“…This has hampered the elucidation of both general, and cycad-specific, cyanobacterial symbiotic signals, especially in elucidating cyanobacterial symbiotic adaptations in both aquatic and terrestrial environments [ 81 ]. Furthermore, it is also unknown how big of a role the associated bacterial community may play in the symbiosis process, and whether their composition is dictated by geography [ 8 21 ], cyanobiont selection [ 5 82 ], host selection [ 37 ] or a combination of all these factors. Here, we present a comprehensive phylogenomic analysis of facultative cyanobionts, coupled with the taxonomic meta-analysis of their associated bacterial community, directly from cycad coralloid roots and in culture.…”

“…2b ). This degree of universal conservation implies selection [ 84 ] that might be based in supporting functional roles [ 37 82 ].…”

Effect of Nitrogen Addition on Tiger Nut (Cyperus esculentus L.) Rhizosphere Microbial Diversity and Drive Factions of Rhizosphere Soil Multifunctionality in Sandy Farmland

“…Rhizosphere microorganisms, a specialized subset, exert their influence in the proximity of the root system. They are attracted to the rhizosphere through root exudates and specialized metabolites [8,10]. The interactions and symbiotic relationships among diverse microbial communities in the rhizosphere play crucial roles in nutrient cycling within the root zone, enhancing plant disease resistance, and ecological adaptation [11].…”