Recovery and Community Succession of theZostera marinaRhizobiome After Transplantation

Abstract

18Seagrasses can form mutualisms with their microbiomes that facilitate the exchange of 19 energy sources, nutrients, and hormones, and ultimately impact plant stress resistance. Little is 20 known about community succession within the belowground seagrass microbiome after 21 disturbance and its potential role in the plant's recovery after transplantation. We transplanted 22 Zostera marina shoots with and without an intact rhizosphere and cultivated plants for four 23 weeks while characterizing microbiome recovery and effects on plant traits. Rhizosphere and 24 root microbiomes were compositionally distinct, likely representing discrete microbial niches. 25 Furthermore, microbiomes of washed transplants were initially different from those of sod 26 transplants, and recovered to resemble an undisturbed state within fourteen days. Conspicuously, 27 changes in microbial communities of washed transplants corresponded with changes in 28 rhizosphere sediment mass and root biomass, highlighting the strength and responsive nature of 29 the relationship between plants, their microbiome, and the environment. Potential mutualistic 30 microbes that were enriched over time include those that function in the cycling and turnover of 31 sulfur, nitrogen, and plant-derived carbon in the rhizosphere environment. These findings 32 highlight the importance and resiliency of the seagrass microbiome after disturbance. 33 Consideration of the microbiome will have meaningful implications on habitat restoration 34 practices. 35Importance 37 Seagrasses are important coastal species that are declining globally, and transplantation 38 can be used to combat these declines. However, the bacterial communities associated with 39 seagrass rhizospheres and roots (the microbiome) are often disturbed or removed completely 40 prior to transplantation. The seagrass microbiome benefits seagrasses through metabolite, 41 nutrient, and phytohormone exchange, and contributes to the ecosystem services of seagrass 42 meadows by cycling sulfur, nitrogen, and carbon. This experiment aimed to characterize the 43 importance and resilience of the seagrass belowground microbiome by transplanting Zostera 44 marina with and without intact rhizospheres and tracking microbiome and plant morphological 45 recovery over four weeks. We found the seagrass microbiome to be resilient to transplantation 46 disturbance, recovering after fourteen days. Additionally, microbiome recovery was linked with 47 seagrass morphology, coinciding with increases in rhizosphere sediment mass and root biomass. 48Results of this study can be used to include microbiome responses in informing future restoration 49 work. 52The rhizobiome has long been recognized to have important impacts on plant growth and 53 health (1). The microbes of the rhizobiome, which directly interact with and are influenced by 54 the roots (2), can benefit their plant hosts through recycling and producing bioavailable nutrients 55 (3-5), increasing disease resistance through competition with or in...

The Prokaryotic Microbiome of Acropora digitifera is Stable under Short-Term Artificial Light Pollution

“…As Symbiodiniaceae are closely associated with nitrogen-fixing bacteria (diazotrophs) [ 6 , 7 , 35 ], it is possible that ALAN exposure may also affect the abundance of these particular microorganisms. In our study, we found that members of Lachnospiraceae, Rhodobacterales, and Caulobacterales, which include known diazotrophs [ 74 , 75 , 76 , 77 , 78 , 79 ], were relatively more abundant in corals subjected to light at night. These bacterial groups have also been found to co-occur with dinoflagellate symbionts of corals [ 80 , 81 ].…”

The microbiota of intertidal macroalgae Fucus distichus is site‐specific and resistant to change following transplant

“…Biofilm dynamics may be a particularly important determinant of the timescale of turnover in host-associated microbial communities. Rapid microbiota turnover, on the order of hours to days, has been demonstrated for highly disturbed or previously uncolonized host surfaces and substrates in marine systems including corals (Ziegler et al, 2017(Ziegler et al, , 2019, macroalgae (Rao et al, 2006;Longford et al, 2019), seagrass (Wang et al, 2021), artificial macroalgal substrates (Lemay et al, 2020;Weigel and Pfister, 2020) and marine particles (Datta et al, 2016). Long-term observations of transplanted marine hosts with mature and unmanipulated biofilms see more gradual microbiota turnover, if any.…”

Seagrass (Zostera marina) transplant experiment reveals core microbiota and resistance to environmental change

“…Methanol is potentially exuded by seagrass as a waste product of metabolism (Crump et al, 2018; Nemecek‐Marshall et al, 1995). Methylophilaceae and Methylophagaceae utilize methanol as a source of carbon and energy (Doronina et al, 2014) and can also be found on seagrass roots and rhizomes at lower abundances (Crump et al, 2018; Martin et al, 2020; Wang et al, 2020). Methylotrophs can produce plant growth promoting hormones and may contribute to stress tolerance in terrestrial plants (Kumar et al, 2019); they may play similar functional roles in seagrass and marine plants.…”

“…While the mechanisms for community stability are uncertain, some host species can maintain their original microbiota after transplanting, while other species exhibit microbiota turnover (Ziegler et al, 2019). Other seagrass transplant experiments investigating belowground microbiota found that seagrass transplanted without its original rhizome microbiota (rhizomes were rinsed with seawater prior to transplanting) can recover its original microbiota within 14 days (Wang et al, 2020), suggesting that host characteristics determine the microbiota.…”

“…Methanol is potentially exuded by seagrass as a waste product of metabolism (Crump et al, 2018;Nemecek-Marshall et al, 1995). Methylophilaceae and Methylophagaceae utilize methanol as a source of carbon and energy (Doronina et al, 2014) and can also be found on seagrass roots and rhizomes at lower abundances (Crump et al, 2018;Martin et al, 2020;Wang et al, 2020).…”