Plants Assemble Species Specific Bacterial Communities from Common Core Taxa in Three Arcto-Alpine Climate Zones

Abstract

Evidence for the pivotal role of plant-associated bacteria to plant health and productivity has accumulated rapidly in the last years. However, key questions related to what drives plant bacteriomes remain unanswered, among which is the impact of climate zones on plant-associated microbiota. This is particularly true for wild plants in arcto-alpine biomes. Here, we hypothesized that the bacterial communities associated with pioneer plants in these regions have major roles in plant health support, and this is reflected in the formation of climate and host plant specific endophytic communities. We thus compared the bacteriomes associated with the native perennial plants Oxyria digyna and Saxifraga oppositifolia in three arcto-alpine regions (alpine, low Arctic and high Arctic) with those in the corresponding bulk soils. As expected, the bulk soil bacterial communities in the three regions were significantly different. The relative abundances of Proteobacteria decreased progressively from the alpine to the high-arctic soils, whereas those of Actinobacteria increased. The candidate division AD3 and Acidobacteria abounded in the low Arctic soils. Furthermore, plant species and geographic region were the major determinants of the structures of the endophere communities. The plants in the alpine region had higher relative abundances of Proteobacteria, while plants from the low- and high-arctic regions were dominated by Firmicutes. A highly-conserved shared set of ubiquitous bacterial taxa (core bacteriome) was found to occur in the two plant species. Burkholderiales, Actinomycetales and Rhizobiales were the main taxa in this core, and they were also the main contributors to the differences in the endosphere bacterial community structures across compartments as well as regions. We postulate that the composition of this core is driven by selection by the two plants.

Cold‐adapted Bacilli isolated from the Qinghai–Tibetan Plateau are able to promote plant growth in extreme environments

“…Samples were enriched for spore‐forming bacteria by heat treatment (10 min at 80°C). Clostridia, which are abundant in low‐temperature environments (Kumar et al ., ) were excluded by using aerobic cultivation conditions. We have screened 1388 isolates (Gram‐positive and endospore‐forming bacteria) for their antagonistic activity against bacterial ( Xanthomonas oryzae ) and fungal plant pathogens ( Sclerotinia sclerotiorum ) (Fig.…”

“…Although they grow optimally in the mesophilic range above 20 C, these microorganisms have developed mechanisms, which give them the ability to continue to grow at temperatures at 10 C and below (Morita, 1975). Whilst the microbiomes present in bulk soil and rhizosphere are dominated by proteobacteria (Philippot et al, 2013), tissues of plants occurring in lowand high-arctic regions display a reduced diversity and harbour Firmicutes and actinobacteria in a considerable extent, although proteobacteria are still dominating (Kumar et al, 2017).…”

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“…However, the relative abundance of Proteobacteria and Firmicutes increased, while that of Acidobacteria decreased from the rhizosphere to the endosphere. These findings are consistent with observations from other plants such as rice (Edwards et al, 2015), maize (Liu et al, 2017), grapes (Zarraonaindia et al, 2015), agave (Coleman-Derr et al, 2015), Brassica stricta (Wagner et al, 2016), Oxyria digyna, and Saxifraga oppositifolia (Kumar et al, 2017). Taken together, these results indicate that there may be some factors that shape the structure of endophytic bacteria acting in different environments and host species.…”

“…These core OTUs accounted for much less than 20% of the total OTUs, but 80% of the abundance of the endophytic bacterial communities. These findings demonstrated that the core endophytic bacteriome was consistent across hosts of the same species grown in different locations, as has been observed in Arabidopsis (Bulgarelli et al, 2012;Lundberg et al, 2012), grapes (Samad et al, 2017) and some other plant species (Kumar et al, 2017).…”

Diversity of Bacterial Microbiota of Coastal Halophyte Limonium sinense and Amelioration of Salinity Stress Damage by Symbiotic Plant Growth-Promoting Actinobacterium Glutamicibacter halophytocola KLBMP 5180

“…The interactions between the plant and the microbiota are complex. To clarify the interaction mechanisms and ecological functions of plant-associated microbiota, it is necessary to investigate their diversity and composition (12). To date, studies of plant microbiota have primarily focused on crop plants and other model plants (13)(14)(15); information about bacterial microbiota structure and function in plants inhabiting special and extreme habitats remains limited.…”