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Microbial function, composition, and distribution play a fundamental role in ecosystem ecology. The interaction between desert plants and their associated microbes is expected to greatly affect their response to changes in this harsh environment. Using comparative analyses, we studied the impact of three desert shrubs, Atriplex halimus (A), Artemisia herba-alba (AHA), and Hammada scoparia (HS), on soil- and leaf-associated microbial communities. DNA extracted from the leaf surface and soil samples collected beneath the shrubs were used to study associated microbial diversity using a sequencing survey of variable regions of bacterial 16S rRNA and fungal ribosomal internal transcribed spacer (ITS1). We found that the composition of bacterial and fungal orders is plant-type-specific, indicating that each plant type provides a suitable and unique microenvironment. The different adaptive ecophysiological properties of the three plant species and the differential effect on their associated microbial composition point to the role of adaptation in the shaping of microbial diversity. Overall, our findings suggest a link between plant ecophysiological adaptation as a 'temporary host' and the biotic-community parameters in extreme xeric environments. [ABSTRACT FROM AUTHOR]

Changes in the soil labile C pools induced by vegetation rehabilitation on semiarid lands are assumed to correlate with changes in the microbial catabolic profiles. To verify this, soil was sampled under the canopies of 12-year-old (R12Y) and 30-year-old (R30Y) planted Caragana microphylla shrubs, as well as native C. microphylla shrubs, all located in the Horqin Sandy Land, China. Community Level Physiological Profiles (CLPPs) of soils were determined to reveal any qualitative and quantitative shifts in soil microbial catabolism linked with the revegetation process. water-soluble C (WSC) and hot-water extractable C (HWEC) were measured to indicate the availability of labile C pools. As the restoration proceeds, soil organic C (C org ) increased 2–3 times at the R30Y habitat compared to the R12Y habitat. The total utilization rate of the 15 C substrates also increased from 0.68 μg CO 2 -C g −1 soil h −1 at the R12Y habitat to 4.90 μg CO 2 -C g −1 soil h −1 at the R30Y habitat, but a slight decline in catabolic diversity, from 2.53 to 2.29, was recorded. Principal component analysis and redundancy analysis revealed that soil microbial communities colonizing the R12Y habitat exhibited an affinity to carbohydrates, which positively correlated to the relative concentration of WSC. Those colonizing the R30Y and native habitats mainly preferred carboxylic acids and 3,4-dihydroxybenzoic acid due to higher C org content and relative concentration of HWEC. [ABSTRACT FROM AUTHOR]

Microbial diversity associated with micropropagated Atriplex species was assessed using microscopy, isolate culturing, and sequencing. Light, electron, and confocal microscopy revealed microbial cells in aseptically regenerated leaves and roots. Clone libraries and tag-encoded FLX amplicon pyrosequencing (TEFAP) analysis amplified sequences from callus homologous to diverse fungal and bacterial taxa. Culturing isolated some seed borne endophyte taxa which could be readily propagated apart from the host. Microbial cells were observed within biofilm-like residues associated with plant cell surfaces and intercellular spaces. Various universal primers amplified both plant and microbial sequences, with different primers revealing different patterns of fungal diversity. Bacterial and fungal TEFAP followed by alignment with sequences from curated databases revealed 7 bacterial and 17 ascomycete taxa in A. canescens, and 5 bacterial taxa in A. torreyi. Additional diversity was observed among isolates and clone libraries. Micropropagated Atriplex retains a complex, intimately associated microbiome which includes diverse strains well poised to interact in manners that influence host physiology. Microbiome analysis was facilitated by high throughput sequencing methods, but primer biases continue to limit recovery of diverse sequences from even moderately complex communities. [ABSTRACT FROM AUTHOR]