Plant endophytes, comprising non-pathogenic bacteria, fungi, and archaea, inhabit various plant parts, including roots, stems, leaves, and seeds. These microorganisms play a crucial role in plant development by enhancing germination, growth, and stress resilience. Seed endophytes, in particular, represent the most adapted and conserved segment of plant microbiota, significantly influencing the initial stages of plant growth and microbial community establishment. This study investigates the impact of environmental and genotypic factors on the endophytic communities of Chenopodium quinoa Willd. (quinoa), a crop notable for its adaptability and nutritional value. We aimed to characterize the core endophytic communities in quinoa seeds and roots from two distinct genotypes under well-watered (WW) and water-deficit (WD) conditions, utilizing various soil infusions as inoculants to explore potential changes in these endophytes. Our findings reveal distinct changes with quinoa seeds exhibiting a high degree of conservation in their endophytic microbiome, even between maternal and offspring seeds, with specific bacterial taxa showing only minor differences. Tissue specificity emerged as a key factor, with seeds maintaining a stable microbial community, while roots exhibited more pronounced shifts, highlighting the tissue-dependent patterns of microbial enrichment. The results highlight the stability and conservation of endophytic communities in quinoa seeds, even under varying water conditions and across different genotypes, emphasizing the role of tissue specificity in shaping microbial associations. These findings suggest that quinoa-associated endophytes, particularly those conserved in seeds, may play a crucial role in enhancing drought resilience. Understanding the dynamics of plant-microbe interactions in quinoa is vital for developing stress-resilient crop varieties, supporting sustainable agricultural practices, and ensuring food security in the face of climate change and environmental challenges.

Boron toxicity (BT) is a significant environmental stressor that negatively affects plant development, yet its molecular mechanisms remain poorly understood. Interestingly, certain toxic concentrations of boron trigger hypocotyl elongation, suggesting a complex hormonal response. In this study, we focus on the role of brassinosteroids (BRs) in mediating this atypical growth. Our findings demonstrate that BT stimulates BR biosynthesis while simultaneously suppressing its inactivation, resulting in sustained BR activity throughout seedling development. Furthermore, we provide evidence that BT disrupts the normal BR negative feedback regulation, potentially converting it into a positive feedback mechanism that amplifies the elongation response. We also show that this response shares mechanistic similarities with thermomorphogenesis, particularly in its reliance on COP1, PIF4, and BR signalling pathways. Loss-of-function mutants of COP1 and PIF4 exhibited reduced hypocotyl elongation, underscoring their essential roles in this process. Although further research is needed to fully clarify the molecular details, our work reveals a previously unrecognised connection between BT responses and thermomorphogenic growth. We also propose a working model to better understand how BR signalling contributes to plant adaptation under BT stress conditions.

Quinoa (Chenopodium quinoa Willd.) is known for its resilience to drought, yet the organ-specific transcriptional mechanisms underlying this trait remain insufficiently characterized. To address this, we investigated long-term drought responses in two contrasting cultivars, a sensitive (F15) and a tolerant (F16) genotype, by analyzing gene expression in leaves and seeds across three key reproductive stages: early (milky), thick, and mature seed development. This study complements previous physiological and biochemical investigations in the same genotypes, offering a deeper understanding of the molecular basis of drought tolerance. Transcriptomic profiling has revealed distinct drought responses based on cultivar and organ. The sensitive cultivar F15 exhibited rapid changes in gene expression, with significant downregulation of photosynthesis- and ribosome-related genes, suggesting growth arrest. In contrast, F16 showed more stable expression patterns and maintained essential metabolic functions longer under stress. Regulation of genes involved in sugar metabolism, raffinose oligosaccharides, phenylpropanoids, and fatty acids varied between the two genotypes and tissues. Hormonal profiling indicated that F16 leaves had reduced jasmonate levels and increased cytokinin accumulation, indicating sustained growth potential. In F15 leaves, salicylic acid (SA) levels increased during the early stages. Additionally, mature F16 seeds showed reduced jasmonoyl-isoleucine levels, reflecting organ-specific and genotype-dependent hormonal changes. These results suggest that drought tolerance in quinoa involves a finely regulated, genotype-specific coordination of gene networks and hormonal pathways that control development, metabolism, and stress responses in an organ-dependent manner. The tolerant cultivar F16 exhibited a more controlled transcriptional and hormonal response under drought, maintaining photosynthetic and metabolic stability while activating protective mechanisms related to sugar and osmolyte metabolism, including raffinose and stachyose biosynthesis, as well as cytokinin-mediated regulation of senescence. This study identifies molecular targets for future breeding efforts to improve quinoa drought tolerance for cultivation in water-limited environments.

Predictions of how the biogeochemical reservoir of marine dissolved organic matter (DOM) will respond to future ocean changes are limited by bulk characterizations that mask a complex network of thousands of individual microbe-molecule interactions. The marine microbial community regulates the transformation and fate of organic carbon by utilizing DOM molecules as the products and reactants of their diverse enzymatic functions. Linking these molecules with the microbial taxa responsible for their utilization requires characterization of both microbial activity and the resulting metabolic footprint. Here we present a time series of the seasonal dynamics of both the exometabolome and the bacterioplankton community at the Bermuda Atlantic Time series Study (BATS) site and show that metabolic functions are greater predictors of DOM composition than microbial taxonomy. Putative exometabolite identifications (gonyol, glucose 6-sulfate, succinate, and trehalose) indicate that at least a portion of the exometabolome contains rapidly remineralized, labile molecules. We hypothesize that observations of seasonal accumulation of these labile molecules result from decoupled enrichments of microbial production and consumption enzymes. Critically, we found the composition of seasonal DOM features was more stable inter-annually than the microbial community structure. By estimating redundancy in the BATS metagenomes of metabolisms responsible for cycling these molecules, we propose a paradigm whereby microbial metabolisms that are essential, either to all or to a subset of marine microbes, determine DOM composition. The molecular-level characterization of DOM achieved herein greatly enhances possibilities for connecting the mechanisms behind the DOM-microbe network that cycle Earth’s largest reservoir of organic carbon.Significance statement Marine dissolved organic matter (DOM) is a major carbon reservoir that serves as a critical control on Earth’s climate. Marine DOM production and removal is largely regulated by microbial activity, but a mechanistic understanding of these processes is lacking. By analyzing individual molecules of DOM across a three-year ocean time series with ultrahigh-resolution mass spectrometry, we found the composition of DOM molecules is more stable inter-annually than the microbial community. We suggest that while the identity of marine microbes may change, essential metabolisms within microbial communities are maintained and thus result in less variability of the DOM composition. Therefore, comprehensive and mechanistic knowledge of metabolic functions and pathways will be critical to predicting the response of marine DOM to future climate-driven changes.### Competing Interest StatementThe authors have declared no competing interest.

Marine viruses are key players of ocean biogeochemistry, profoundly influencing microbial community ecology and evolution. Despite their importance, few studies have explored continuous inter-seasonal viral metagenomic time series in marine environments. Viral dynamics are complex, influenced by multiple factors such as host population dynamics and environmental conditions. To disentangle the complexity of viral communities, we developed an unsupervised machine learning framework to classify viral contigs into "chronotypes" based on temporal abundance patterns. Analysing an inter-seasonal monthly time series of surface viral metagenomes from the Western English Channel, we identified chronotypes and compared their functional and evolutionary profiles. Results revealed a consistent annual cycle with steep compositional changes from winter to summer and steadier transitions from summer to winter. Seasonal chronotypes were enriched in potential auxiliary metabolic genes of the ferrochelatases and 2OG-Fe(II) oxygenase orthologous groups compared to non-seasonal types. Chronotypes clustered into four groups based on their correlation profiles with environmental parameters, primarily driven by temperature and nutrients. Viral contigs exhibited a rapid turnover of polymorphisms, akin to Red Queen dynamics. However, within seasonal chronotypes, some sequences exhibited annual polymorphism recurrence, suggesting that a fraction of the seasonal viral populations evolve more slowly. Classification into chronotypes revealed viral genomic signatures linked to temporal patterns, likely reflecting metabolic adaptations to environmental fluctuations and host dynamics. This novel framework enables the identification of long-term trends in viral composition, environmental influences on genomic structure, and potential viral interactions.

The skin of fish contains a diverse microbiota that has symbiotic functions with the host, facilitating pathogen exclusion, immune system priming, and nutrient degradation. The composition of fish skin microbiomes varies across species and in response to a variety of stressors, however, there has been no systematic analysis across these studies to evaluate how these factors shape fish skin microbiomes. Here, we examined 1922 fish skin microbiomes from 36 studies that included 98 species and nine rearing conditions to investigate associations between fish skin microbiome, fish species, and water physiochemical factors. Proteobacteria, particularly the class Gammaproteobacteria, were present in all marine and freshwater fish skin microbiomes. Acinetobacter, Aeromonas, Ralstonia, Sphingomonas and Flavobacterium were the most abundant genera within freshwater fish skin microbiomes, and Alteromonas, Photobacterium, Pseudoalteromonas, Psychrobacter and Vibrio were the most abundant in saltwater fish. Our results show that different culturing (rearing) environments have a small but significant effect on the skin bacterial community compositions. Water temperature, pH, dissolved oxygen concentration, and salinity significantly correlated with differences in beta-diversity but not necessarily alpha-diversity. To improve study comparability on fish skin microbiomes, we provide recommendations for approaches to the analyses of sequencing data and improve study reproducibility.

ABSTRACT Microbial processes operate at the microscale, which is not resolved by existing ecosystem models. Here, we present a novel model that simulates a 1 mL three-dimensional cube using a hybrid Lagrangian–Eulerian approach, at ecologically relevant timescales. The model simulates individual microbes, including three phytoplankton size classes with healthy, senescent, and dead lifecycle stages; copiotrophic and oligotrophic heterotrophic bacteria; and dissolved organic matter at 50 µm resolution. Diffusion, shear, sedimentation, chemotaxis, and attachment processes are explicitly resolved. The emerging quantitative representation of the ecosystem shows that (1) copiotrophs grow mostly attached to eukaryotic phytoplankters and get almost all of their carbon from them vs. oligotrophs that grow on exudates and lysates of cyanobacteria; (2) contrasting diel patterns in substrate appearance in the phycosphere vs. ambient water and growth of particle-associated copiotrophs vs. free-living oligotrophs; (3) attached bacteria reduce carbon flux from the phycosphere, lowering chemotactic efficiency toward eukaryotes below that toward cyanobacteria; (4) shear reduces chemotactic efficiency and fitness of the copiotroph; and (5) the main benefit of chemotaxis is to locate attachment partners. These patterns are consistent with available observations. Our study provides insights into the microscale ecology of marine bacteria, and the open-source code is a tool for further research in this area. IMPORTANCE A large amount of global CO 2 fixation is performed by marine phytoplankton, and a substantial fraction of that is released as dissolved organic carbon and further processed by heterotrophic bacteria. The interaction between phytoplankton and bacteria, i.e., the carbon flux between them, is therefore an important process in the global carbon and climate system. Some bacteria have developed specialized behavioral traits, like swimming and attachment, to increase their carbon acquisition. These interactions occur at the micrometer scale, for example, the immediate vicinity of phytoplankters (the phycosphere), but existing biogeochemical models typically only simulate down to the 1 meter vertical or ~100 kilometer horizontal scale. We present a new microscale model and use it to predict fluxes and other features in the surface ocean. The model makes important predictions about the fluxes between various types of phytoplankton and bacteria and the role of behavioral traits, and it provides a basis and tool for further research in this area.

The composition of the marine phytoplankton community has been shown to impact many biogeochemical processes and marine ecosystem services. A variety of methods exist to characterize phytoplankton community composition (PCC), with varying degrees of taxonomic resolution. Accordingly, the resulting PCC determinations are dependent on the method used. Here, we use surface ocean samples collected in the North Atlantic and North Pacific Oceans to compare high performance liquid chromatography (HPLC) pigment-based PCC to four other methods: quantitative cell imaging, flow cytometry, and 16S and 18S rRNA amplicon sequencing. These methods allow characterization of both prokaryotic and eukaryotic PCC across a wide range of size classes. PCC estimates of many taxa resolved at the class level (e.g., diatoms) show strong positive correlations across methods, while other groups (e.g., dinoflagellates) are not well captured by one or more methods. Since variations in phytoplankton pigment concentrations are related to changes in optical properties, this combined dataset expands the potential scope of ocean color remote sensing by associating PCC at the genus- and species-level with group- or class-level PCC from pigments. Quantifying the strengths and limitations of pigment-based PCC methods compared to PCC assessments from amplicon sequencing, imaging, and cytometry methods is the first step toward the robust validation of remote sensing approaches to quantify PCC from space.

AbstractOcean spring phytoplankton blooms are dynamic periods important to global primary production. We document vertical patterns of a diverse suite of eukaryotic algae, the prasinophytes, in the North Atlantic Subtropical Gyre with monthly sampling over four years at the Bermuda Atlantic Time-series Study site. Water column structure was used to delineate seasonal stability periods more ecologically relevant than seasons defined by calendar dates. During winter mixing, tiny prasinophytes dominated by Class II comprise 46 ± 24% of eukaryotic algal (plastid-derived) 16S rRNA V1-V2 amplicons, specifically Ostreococcus Clade OII, Micromonas commoda, and Bathycoccus calidus. In contrast, Class VII are rare and Classes I and VI peak during warm stratified periods when surface eukaryotic phytoplankton abundances are low. Seasonality underpins a reservoir of genetic diversity from multiple prasinophyte classes during warm periods that harbor ephemeral taxa. Persistent Class II sub-species dominating the winter/spring bloom period retreat to the deep chlorophyll maximum in summer, poised to seed the mixed layer upon winter convection, exposing a mechanism for initiating high abundances at bloom onset. Comparisons to tropical oceans reveal broad distributions of the dominant sub-species herein. This unparalleled window into temporal and spatial niche partitioning of picoeukaryotic primary producers demonstrates how key prasinophytes prevail in warm oceans.

Dominant microorganisms of the Sargasso Sea are key drivers of the global carbon cycle. However, associated viruses that shape microbial community structure and function are not well characterised. Here, we combined short and long read sequencing to survey Sargasso Sea phage communities in virus- and cellular fractions at viral maximum (80 m) and mesopelagic (200 m) depths. We identified 2,301 Sargasso Sea phage populations from 186 genera. Over half of the phage populations identified here lacked representation in global ocean viral metagenomes, whilst 177 of the 186 identified genera lacked representation in genomic databases of phage isolates. Viral fraction and cell-associated viral communities were decoupled, indicating viral turnover occurred across periods longer than the sampling period of three days. Inclusion of long-read data was critical for capturing the breadth of viral diversity. Phage isolates that infect the dominant bacterial taxa Prochlorococcus and Pelagibacter, usually regarded as cosmopolitan and abundant, were poorly represented. The Sargasso Sea is a natural laboratory for understanding future conditions of warmer oceans and associated nutrient limitation. Here, the authors combined short- and long-read sequencing to survey Sargasso Sea viral communities.

Viral outbreaks are a constant threat to aquaculture, limiting production for better global food security. A lack of diagnostic testing and monitoring in resource-limited areas hinders the capacity to respond rapidly to disease outbreaks and to prevent viral pathogens becoming endemic in fisheries productive waters. Recent developments in diagnostic testing for emerging viruses, however, offers a solution for rapid in situ monitoring of viral outbreaks. Genomic epidemiology has furthermore proven highly effective in detecting viral mutations involved in pathogenesis and assisting in resolving chains of transmission. Here, we demonstrate the application of an in-field epidemiological tool kit to track viral outbreaks in aquaculture on farms with reduced access to diagnostic labs, and with non-destructive sampling. Inspired by the “lab in a suitcase” approach used for genomic surveillance of human viral pathogens and wastewater monitoring of COVID19, we evaluated the feasibility of real-time genome sequencing surveillance of the fish pathogen, Infectious spleen and kidney necrosis virus (ISKNV) in Lake Volta. Viral fractions from water samples collected from cages holding Nile tilapia ( Oreochromis niloticus ) with suspected ongoing ISKNV infections were concentrated and used as a template for whole genome sequencing, using a previously developed tiled PCR method for ISKNV. Mutations in ISKNV in samples collected from the water surrounding the cages matched those collected from infected caged fish, illustrating that water samples can be used for detecting predominant ISKNV variants in an ongoing outbreak. This approach allows for the detection of ISKNV and tracking of the dynamics of variant frequencies, and may thus assist in guiding control measures for the rapid isolation and quarantine of infected farms and facilities.

Marine viruses are key players of ocean biogeochemistry, profoundly influencing microbial community ecology and evolution. Despite their importance, few studies have explored the temporal dynamics of viral genome abundances in marine environments. Viral dynamics are complex, influenced by multiple factors such as host population dynamics and environmental conditions. To disentangle the complexity of viral communities, we developed an unsupervised machine learning framework to classify viral genomes into "chronotypes" based on temporal abundance patterns. Analysing an inter-seasonal monthly time-series of surface viral metagenomes from the Western English Channel, we identified chronotypes and compared their functional and evolutionary profiles. Results revealed a consistent annual cycle with steep compositional changes from winter to summer and steadier transitions from summer to winter. Seasonal chronotypes were enriched in potential auxiliary metabolic genes like ferrochelatases and 2OG-Fe(II) oxygenases compared to non-seasonal types. Chronotypes clustered into four groups based on their correlation profiles with environmental parameters, primarily driven by temperature and nutrients. Viral genomes exhibited a rapid turnover of polymorphisms, akin to Red Queen dynamics. However, within seasonal chronotypes, some sequences exhibited annual polymorphism recurrence, which declined over a 16-month period, suggesting that a fraction of the seasonal viral populations evolve more slowly. Classification into chronotypes revealed viral genomic signatures linked to temporal patterns, likely reflecting metabolic adaptations to environmental fluctuations and host dynamics. This novel framework enables the identification of long-term trends in viral composition, environmental influences on genomic structure, and potential viral interactions.### Competing Interest StatementThe authors have declared no competing interest.

Chenopodium quinoa (quinoa) is an underutilized crop proposed as key to achieving food security within the current climatic context, where water scarcity in rainfed areas is becoming more frequent and severe, especially in Mediterranean regions. Thus, aiming at deepening our knowledge regarding the impact of water limitation on the quinoa seed nutritional quality, seeds obtained from primary and secondary panicles of four different European-adapted cultivars (F14, F15, F16, and Titicaca) growing under full irrigation and water-limiting conditions, were here analyzed. A set of parameters were evaluated in this work, including agronomical (such as yield, seed weight, seed area, and seed germination and viability rates) and nutritional (including the seed proximate composition, mineral content, and antioxidants) traits. Our results indicate that the morphological changes associated with drought stress affect secondary panicles’ seed yield. This phenomenon was generally associated with an improvement in the nutritional quality of those seeds. However, cultivars such as F16, despite keeping total seed yield under low water availability, showed drought's detrimental effect on the seed nutritional quality. In contrast, cultivars like F15 and Titicaca reduced their seed yield under water-limiting conditions but increased their protein, iron, copper, calcium, manganese, and zinc contents, especially in secondary panicles. Therefore, the dichotomy between seed quantity and quality has to be considered in this crop under water stress scenarios, highlighting differences in sink strength along the plant panicles determining seed nutritional quality.

Quinoa is an Andean crop whose cultivation has been extended to many different parts of the world in the last decade. It shows a great capacity for adaptation to diverse climate conditions, including environmental stressors, and, moreover, the seeds are very nutritious in part due to their high protein content, which is rich in essential amino acids. They are gluten-free seeds and contain good amounts of other nutrients such as unsaturated fatty acids, vitamins, or minerals. Also, the use of quinoa hydrolysates and peptides has been linked to numerous health benefits. Altogether, these aspects have situated quinoa as a crop able to contribute to food security worldwide. Aiming to deepen our understanding of the protein quality and function of quinoa seeds and how they can vary when this crop is subjected to water-limiting conditions, a shotgun proteomics analysis was performed to obtain the proteomes of quinoa seeds harvested from two different water regimes in the field: rainfed and irrigated conditions. Differentially increased levels of proteins determined in seeds from each field condition were analysed, and the enrichment of chitinase-related proteins in seeds harvested from rainfed conditions was found. These proteins are described as pathogen-related proteins and can be accumulated under abiotic stress. Thus, our findings suggest that chitinase-like proteins in quinoa seeds can be potential biomarkers of drought. Also, this study points to the need for further research to unveil their role in conferring tolerance when coping with water-deficient conditions.

The SAR11 clade are the most abundant members of surface marine bacterioplankton and a critical component of global biogeochemical cycles. Similarly, pelagiphages that infect SAR11 are ubiquitous and highly abundant in the oceans. Pelagiphages are predicted to shape SAR11 community structures and increase carbon turnover throughout the oceans. Yet, ecological drivers of host and niche specificity of pelagiphage populations are poorly understood. Here we report the global distribution of a novel pelagiphage called “Polarivirus skadi”, which is the sole representative of a novel genus. P. skadi was isolated from the Western English Channel using a cold-water ecotype of SAR11 as bait. P. skadi is closely related to the globally dominant pelagiphage HTVC010P. Along with other HTVC010P-type viruses, P. skadi belongs to a distinct viral family within the order Caudovirales, for which we propose the name Ubiqueviridae. Metagenomic read recruitment identified P. skadi as one of the most abundant pelagiphages on Earth. P. skadi is a polar specialist, replacing HTVC010P at high latitudes. Experimental evaluation of P. skadi host range against cold- and warm-water SAR11 ecotypes supported cold-water specialism. Relative abundance of P. skadi in marine metagenomes correlated negatively with temperature, and positively with nutrients, available oxygen, and chlorophyll concentrations. In contrast, relative abundance of HTVC010P correlated negatively with oxygen and positively with salinity, with no significant correlation to temperature. The majority of other pelagiphages were scarce in most marine provinces, with a few representatives constrained to discrete ecological niches. Our results suggest that pelagiphage populations persist within a global viral seed bank, with environmental parameters and host availability selecting for a few ecotypes that dominate ocean viromes.

Oxygen minimum zones (OMZs) are expanding due to increased sea surface temperatures, subsequent increased oxygen demand through respiration, reduced oxygen solubility, and thermal stratification driven in part by anthropogenic climate change. Devil’s Hole, Bermuda is a model ecosystem to study OMZ microbial biogeochemistry because the formation and subsequent overturn of the suboxic zone occur annually. During thermally driven stratification, suboxic conditions develop, with organic matter and nutrients accumulating at depth. In this study, the bioavailability of the accumulated dissolved organic carbon (DOC) and the microbial community response to reoxygenation of suboxic waters was assessed using a simulated overturn experiment. The surface inoculated prokaryotic community responded to the deep (formerly suboxic) 0.2 μm filtrate with cell densities increasing 2.5-fold over 6 days while removing 5 μmol L−1 of DOC. After 12 days, the surface community began to shift, and DOC quality became less diagenetically altered along with an increase in SAR202, a Chloroflexi that can degrade recalcitrant dissolved organic matter (DOM). Labile DOC production after 12 days coincided with an increase of Nitrosopumilales, a chemoautotrophic ammonia oxidizing archaea (AOA) that converts ammonia to nitrite based on the ammonia monooxygenase (amoA) gene copy number and nutrient data. In comparison, the inoculation of the deep anaerobic prokaryotic community into surface 0.2 μm filtrate demonstrated a die-off of 25.5% of the initial inoculum community followed by a 1.5-fold increase in cell densities over 6 days. Within 2 days, the prokaryotic community shifted from a Chlorobiales dominated assemblage to a surface-like heterotrophic community devoid of Chlorobiales. The DOM quality changed to less diagenetically altered material and coincided with an increase in the ribulose-1,5-bisphosphate carboxylase/oxygenase form I (cbbL) gene number followed by an influx of labile DOM. Upon reoxygenation, the deep DOM that accumulated under suboxic conditions is bioavailable to surface prokaryotes that utilize the accumulated DOC initially before switching to a community that can both produce labile DOM via chemoautotrophy and degrade the more recalcitrant DOM.

Highlights• Quinoa primary and secondary panicles show distinct nutritional quality.• The drought-sensitive genotypes showed larger yields in the secondary panicles.• Secondary panicle seeds stood out by their protein, fiber, iron, calcium, copper, manganese, and zinc contents.• Water stress reduced the fat content of primary panicles but increased the protein and iron contents.• The drought-tolerant genotype F16 yielded seeds of lesser quality seed.

In the original publication [...].

On the eve of the 100th anniversary of Dr. Warington's discovery of boron (B) as a nutrient essential for higher plants, "boronists" have struggled to demonstrate a role beyond its structural function in cell walls dimerizing pectin molecules of rhamnogalacturonan II (RGII). In this regard, B deficiency has been associated with a plethora of symptoms in plants that include macroscopic symptoms like growth arrest and cell death and biochemical or molecular symptoms that include changes in cell wall pore size, apoplast acidification, or a steep ROS production that leads to an oxidative burst. Aiming to shed light on B functions in plant biology, we proposed here a unifying model integrating the current knowledge about B function(s) in plants to explain why B deficiency can cause such remarkable effects on plant growth and development, impacting crop productivity. In addition, based on recent experimental evidence that suggests the existence of different B ligands other than RGII in plant cells, namely glycolipids, and glycoproteins, we proposed an experimental pipeline to identify putative missing ligands and to determine how they would integrate into the above-mentioned model.

Tilapia farming is one of the most important sectors in aquaculture worldwide and of major importance to global food security. Infectious spleen and kidney necrosis virus (ISKNV) has been identified as an agent of high morbidity and mortality, threatening tilapia aquaculture. ISKNV was detected in Lake Volta, Ghana, in September 2018 and spread rapidly, with mortality rates between 60 and 90% and losses of more than 10 tonnes of fish per day. Understanding the spread and evolution of viral pathogens is important for control strategies. Here, we developed a tiled-PCR sequencing approach for the whole-genome sequencing of ISKNV, using long read sequencing to enable field-based, real-time genomic surveillance. This work represents the first use of tiled-PCR for whole genome recovery of viruses in aquaculture, with the longest genome target (>110 kb dsDNA) to date. Our protocol was applied to field samples collected from the ISKNV outbreaks from four intensive tilapia cage culture systems across Lake Volta, between October 2018 and May 2022. Despite the low mutation rate of dsDNA viruses, 20 single nucleotide polymorphisms accumulated during the sampling period. Droplet digital PCR identified a minimum requirement of template in a sample to recover 50% of an ISKNV genome at 275 femtograms (2410 viral templates per 5 µL sequencing reaction). Overall, tiled-PCR sequencing of ISKNV provides an informative tool to assist in disease control in aquaculture.