Exploring microbiomes for plant disease management

Antonino Malacrinò, Ahmed Abdelfattah, Gabriele Berg, Maria-Soledad Benitez, Alison E.Bennett, Laura Böttner, Shuqing Xu, Leonardo Schena. Biological Control. March 2022, 104890. https://doi.org/10.1016/j.biocontrol.2022.104890

Abstract

Microbiome science is revolutionizing many concepts of plant biology, ecology, and evolution. Understanding plant microbiomes is key to developing solutions that protect crop health without impacting the environment. In this perspective article, we highlight the importance of both the structure and functions of plant-associated microbial communities in protecting their host from pathogens. These new findings have a high potential to aid biocontrol programs and to replace traditional chemical products, guiding the transition towards a sustainable production.

The Costs and Benefits of Plant–Arbuscular Mycorrhizal Fungal Interactions

Alison E. Bennett and Karin Groten. Annual Review of Plant Biology. Vol. 73:- Volume publication date May 2022. https://doi.org/10.1146/annurev-arplant-102820-124504

Abstract

The symbiotic interaction between plants and arbuscular mycorrhizal (AM) fungi is often perceived as beneficial for both partners, though a large ecological literature highlights the context dependency of this interaction. Changes in abiotic variables, such as nutrient availability, can drive the interaction along the mutualism-parasitism continuum with variable outcomes for plant growth and fitness. However, AM fungi can benefit plants in more ways than improved phosphorus nutrition and plant growth. For example, AM fungi can promote abiotic and biotic stress tolerance even when considered parasitic from a nutrient provision perspective. Other than being obligate biotrophs, very little is known about the benefits AM fungi gain from plants. In this review, we utilize both molecular biology and ecological approaches to expand our understanding of the plant–AM fungal interaction across disciplines.

Physiological acclimatization in Hawaiian corals following a 22-month shift in baseline seawater temperature and pH

Rowan H. McLachlan, James T. Price, Agustí Muñoz-Garcia, Noah L. Weisleder, Stephen J. Levas, Christopher P. Jury, Robert J. Toonen & Andréa G. Grottoli. Sci Rep 12, 3712 (2022). https://doi.org/10.1038/s41598-022-06896-z

Abstract

Climate change poses a major threat to coral reefs. We conducted an outdoor 22-month experiment to investigate if coral could not just survive, but also physiologically cope, with chronic ocean warming and acidification conditions expected later this century under the Paris Climate Agreement. We recorded survivorship and measured eleven phenotypic traits to evaluate the holobiont responses of Hawaiian coral: color, Symbiodiniaceae density, calcification, photosynthesis, respiration, total organic carbon flux, carbon budget, biomass, lipids, protein, and maximum Artemia capture rate. Survivorship was lowest in Montipora capitata and only some survivors were able to meet metabolic demand and physiologically cope with future ocean conditions. Most M. capitata survivors bleached through loss of chlorophyll pigments and simultaneously experienced increased respiration rates and negative carbon budgets due to a 236% increase in total organic carbon losses under combined future ocean conditions. Porites compressa and Porites lobata had the highest survivorship and coped well under future ocean conditions with positive calcification and increased biomass, maintenance of lipids, and the capacity to exceed their metabolic demand through photosynthesis and heterotrophy. Thus, our findings show that significant biological diversity within resilient corals like Porites, and some genotypes of sensitive species, will persist this century provided atmospheric carbon dioxide levels are controlled. Since Porites corals are ubiquitous throughout the world’s oceans and often major reef builders, the persistence of this resilient genus provides hope for future reef ecosystem function globally.

Using solid-phase microextraction during ultrasound reveals higher aqueous PAHs release from contaminated sediment

Danielle S.Kohan, Roman P.Lanno, Linda K.Weavers. Ultrasonics Sonochemistry, Volume 85, 2022, 105981, ISSN 1350-4177, https://doi.org/10.1016/j.ultsonch.2022.105981.
(https://www.sciencedirect.com/science/article/pii/S1350417722000748)

Abstract

Ultrasound (US) releases polycyclic aromatic hydrocarbons (PAHs) from contaminated creosote sediments and degrades PAHs in aqueous solution. However, it is unclear how much PAHs release occurs during active US compared to after US is stopped. In this study, solid-phase microextraction (SPME) was used to determine aqueous PAH concentrations desorbed from Little Scioto River creosote contaminated sediment during exposure to 20 kHz ultrasound (US) at a power of 430 W L−1. First, SPME fiber-water partition coefficients, K SPME, were experimentally determined and shown to be comparable with previous studies. Next, PAH concentrations released into aqueous solution were determined by sequentially exposing fresh, conditioned SPME fibers in a reactor containing the contaminated sediment and DI for 10 min periods. Three consecutive 10 min periods each were measured during US and after US. Compared to mixing only, PAHs desorbed during ultrasound was significantly higher. In addition, for phenanthrene, anthracene, and fluoranthene, US showed significantly higher aqueous concentrations during US compared with after US. For these less soluble PAHs, desorption into the aqueous phase reaches and surpasses expected equilibrium aqueous concentrations. However, when US is ceased, PAHs appear to resorb onto sediment resulting in the lower concentrations measured in these PAH compounds after US that are similar to expected equilibrium aqueous concentrations. Typical analytical extraction methods for determining the effects of US require stopping treatment and may underestimate the potential US has for release of contaminants from sediment during US. Using SPME during US treatment reveals that the concentration of PAHs during US may surpass the expected equilibrium aqueous concentration of some PAHs congeners. To our knowledge, this higher concentration observed during US compared to after US has not been shown previously.

Community stability is related to animal diversity change

Marta A. Jarzyna, Matthew R. Helmus, Mariana Perez Rocha, Phoebe L. Zarnetske, Kari E. A. Norman, Daijiang Li, Jalene M. LaMontagne, tephanie M. Parker, Sydne Record, Thilina D. Surasinghe. Ecosphere. 2022;13:e3970. https://onlinelibrary.wiley.com/r/ecs2. https://doi.org/10.1002/ecs2.3970

Abstract

Understanding the drivers of community stability in times of increasing anthropogenic pressure is an urgent issue. Biodiversity is known to promote community stability, but studies of the biodiversity–stability relationship rarely consider the full complexity of biodiversity change. Furthermore, finding generalities that hold across taxonomic groups and spatial and temporal scales remains challenging because most investigations have narrow taxonomic, spatial, and temporal scopes. We used organismal data collected through the National Ecological Observatory Network (NEON) at sites across the contiguous United States to evaluate linkages between community stability and biodiversity change for four taxonomic groups: small mammals, ground beetles, fish, and freshwater macroinvertebrates. We defined community stability as constancy of aggregate species’ abundance. We quantified change in biodiversity as (1) dissimilarity in community taxonomic and functional composition and species replacement and richness change components of that dissimilarity and (2) change in species’ abundance distributions as captured by change in species rank, richness, and evenness. We found that community stability increased with species replacement and with contribution of species replacement to overall dissimilarity for all taxonomic groups, but declined with increasing change in species richness and evenness. This is consistent with the notion that temporal fluctuations in species abundance can help stabilize community properties. We also found that community stability was highest when change in community functional composition was either lower or higher than expected given reshuffling of each community’s taxonomic composition. This suggests that long-term community stability can result from fluctuations of functionally similar species in assemblages with high taxonomic reshuffling. On the contrary, the functional uniqueness of fluctuating species compensates for lower taxonomic reshuffling to drive stabilization of community properties. Our study provides an initial assessment of the relationship between community stability and biodiversity change and illustrates the utility of fine temporal resolution data collected across ecosystems and biomes to understand the general mechanisms underlying biodiversity–stability relationships.

Genomic evidence of an ancient Inland Temperate Rainforest in the Pacific Northwest of North America

Megan Ruffley, Megan L. Smith, Anahí Espíndola, Daniel F. Turck, Niels Mitchell, Bryan Carstens, Jack Sullivan, David C. Tank. 2022. Molecular Ecology. https://doi.org/10.1111/mec.16431

Abstract

The disjunct temperate rainforests of the Pacific Northwest of North America (PNW) are characterized by late-successional dominant tree species Thuja plicata (western redcedar) and Tsuga heterophylla (western hemlock). The demographic histories of these species, along with the PNW rainforest ecosystem in its entirety, have been heavily impacted by geological and climatic changes the PNW has experienced over the last 5 million years, including mountain orogeny and repeated Pleistocene glaciations. These environmental events have ultimately shaped the history of these species, with inland populations potentially being extirpated during the Pleistocene glaciations. Here, we collect genomic data for both species across their ranges to test multiple demographic models, each reflecting a different phylogeographic hypothesis on how the ecosystem-dominating species may have responded to dramatic climatic change. Our results indicate that inland and coastal populations in both species diverged approximately 2.5 million years ago in the early Pleistocene and experienced decreases in population size during glacial cycles, with subsequent population expansion. Importantly, we found evidence for gene flow between coastal and inland populations during the mid-Holocene. It is likely that intermittent migration in these species during this time has prevented allopatric speciation via genetic drift alone. In conclusion, our results from combining genomic data and demographic inference procedures establish that populations of the ecosystem dominants Thuja plicata and Tsuga heterophylla persisted in refugia located in both the coastal and inland regions of the PNW throughout the Pleistocene, with populations expanding and contracting in response to glacial cycles with occasional gene-flow.