Early Bloom Research Articles

Functional Studies on the LiAG1 Gene of Lilium ‘Ice Pink Queen’ in Flower Development

Lily (Lilium Asiatica Hybrida) is a globally known perennial herbaceous bulbous flower, popular for its large, colourful flowers and high economic and ornamental value. However, pollen generation is a severe issue that reduces the cosmetic value of lilies. In this study, the MADS transcription factor LiAG1 was isolated and identified from the Lilium Asiatica Hybrida ‘Ice Pink Queen’, a male-sterile variety obtained through several years of hybridisation in our laboratory. qRT-PCR revealed that LiAG1 expression was greater in lily anthers, especially during the half-opening stage. The transient expression in tobacco demonstrated that LiAG1 was located in the nucleus. In the ‘Ice Pink Queen’ lily, suppression of LiAG1 using TRV-VIGS (tobacco-rattle-virus-mediated virus-induced gene silencing) resulted in the disappearance of most of the tapetum layer and the absence of the microsporangia. Overexpression of LiAG1 in transgenic Arabidopsis and tobacco resulted in narrower and more involute leaves, plant dwarfing, earlier blooming, and better pollen viability. Overall, our results suggested that LiAG1 might play an important role in flower development, especially anther development, of Lilium Asiatica Hybrida ‘Ice Pink Queen’.

Metaproteomics reveals metabolic activities potentially involved in bloom formation and succession during a mixed dinoflagellate bloom of Prorocentrum obtusidens and Karenia mikimotoi.

Understanding metabolic activities involved in bloom formation during a single-species algal bloom has improved greatly. However, little is known about metabolic activities during a multi-species algal bloom. Here, we investigated protein expression profiles at different bloom stages of a mixed dinoflagellate bloom caused by Karenia mikimotoi and Prorocentrum obtusidens (syn. Prorocentrum donghaiense) using a metaproteomic approach. Our results indicated that both P. obtusidens and K. mikimotoi cells highly expressed proteins associated with essential cellular metabolisms such as cell growth and nutrient acquisition before their respective bloom occurrence. P. obtusidens preferentially enhanced uptake and utilization of ammonium, amino acid and organophosphorus-like phospholipid at the early bloom stage, and expressed highly abundant chloroplast peridinin-chlorophyll a-binding protein at the early and the P. obtusidens-dominated bloom stages, indicating their important roles in preferential occurrence and maintenance of P. obtusidens bloom. While absorption and utilization of nutrients, especially ammonium, urea, cyanate, phospholipid, and nucleotide, as well as endocytosis, in K. mikimotoi cells, were enhanced. Notably, both species increased photosynthesis, energy generation, cell proliferation, cell motility and cell defense before their respective blooms, which were beneficial to dealing with adverse external stresses, enabling them to be more competitive and advantageous in complex environments. Interestingly, diatom groups (Skeletonema, Pseudo-nitzschia, and Thalassiosira) decreased uptake and utilization of ambient nutrients and cell proliferation during the bloom period. This study demonstrates that niche differentiation and functional complementarity among phytoplankton species regulate bloom formation and succession during the mixed bloom.

Phytoplankton community composition links to environmental drivers across a fjord to shelf gradient on the central coast of British Columbia

Rapid environmental change is altering coastal phytoplankton dynamics and, thereby the productivity of coastal marine food webs. Unfortunately, a paucity of phytoplankton community data hinders the prediction of future conditions in ecologically productive regions such as the coastal northeast Pacific. To help fill this gap, this study characterized phytoplankton communities from 2018 to 2020 across a fjord, channel and shelf station transect on the central coast of British Columbia, Canada. Monthly samples were collected for microscopy-based taxonomy and pigment-based phytoplankton composition (i.e. CHEMTAX and size-fractionated chlorophyll). Correlation analysis was used to investigate drivers of phytoplankton biomass and hierarchical clustering and redundancy analysis highlighted drivers of compositional trends. Spring blooms formed the peak of annual biomass at each station and earlier blooms at the fjord station suggested a sheltering effect from winter wind conditions. Later spring blooms at the channel station coincided with seasonal wind reductions and increased sunlight. Of the six derived compositional clusters, three represented flagellate dominated conditions at all stations: two represented low biomass winter conditions and the third, moderate biomass spring and autumn blooms occurring under nutrient replete conditions. The remaining three clusters were diatom-dominated and spanned much of the growing season. The first diatom cluster represented Skeletonema marinoi dominated samples, many from 2020, observed under moderate nutrient and high stratification and freshwater discharge conditions. The second represented high diatom richness spring bloom conditions at all stations that were associated with nutrient depletion. Finally, the third included 2018 and 2019 summer shelf samples showing harmful Rhizosolenia setigera and Pseudo-nitzschia seriata blooms under high surface water salinity and temperature. These results highlight high spatial-temporal variability and sensitivity of coastal northeast Pacific phytoplankton communities to altered freshwater, temperature and wind dynamics with potential for profound ecosystem level implications.

Identification and Correlation Analysis of Key Clostridia and LAB Species in Alfalfa Silages Prepared with Different Cultivars and Additives

Clostridial fermentation is the determining process causing the spoilage of direct-cut alfalfa silage, and the application of lactic acid bacteria (LAB) inoculant is considered as the most promising technology for inhibiting clostridial fermentation. In order to screen target-based LAB strains, identification and correlation analysis of key Clostridia and LAB species in alfalfa silage were conducted in this study. Three alfalfa cultivars (Sanditi, SD; Celsius, CE; SW5909, SW) were harvested at the early bloom stage and ensiled without (CK) or with LAB inoculant (LB) and sucrose (SC) for 60 d. Single-molecule real-time sequencing was used to identify dominant Clostridia and LAB species, and LAB with significant inhibitory effects on dominant Clostridia was screened via correlation network analysis. The results showed that silages CK and LB encountered severe clostridial fermentation as indicated by large amounts of butyric acid (BA) and ammoniacal nitrogen (NH3-N) production. Compared to silages CK and LB, SC treatment decreased (p < 0.05) BA and NH3-N concentrations, as well as decreasing (p < 0.05) the bacterial community indexes of Shannon and Chao1. Lactiplantibacillus pentosus was the first dominant LAB in silage CK of alfalfa SD and CE. The first dominant LAB in silage LB was also identified as L. pentosus, rather than Lentilactobacillus buchneri and Lactiplantibacillus plantarum in the used inoculant. L. buchneri became more abundant in silage SC of alfalfa SD and CE, accounting for the high fermentation quality of these silages. Clostridium tyrobutyricum, Clostridium luticellarii, Garciella sp._GK3, Clostridium sporogenes, Clostridium perfringens, and Clostridium sp._BTY5 were the most dominant Clostridia species in alfalfa silage. Furthermore, Enterococcus faecalis, L. buchneri, and L. pentosus exhibited significant (p < 0.05) inhibitory effects on C. tyrobutyricum, C. luticellarii, and Garciella sp._GK3, respectively, which were the top three Clostridia species associated with clostridial fermentation. In conclusion, E. faecalis, L. buchneri, and L. pentosus were screened and can be used as potential LAB inoculants for the targeted inhibition of clostridial fermentation.

Effects of reflective material deployed at bloom for 1, 2 or 5 months on ‘WA 38’ apple fruit set, quality and yield

The self-thinning nature of the apple variety ‘WA 38’ was previously characterized in Washington State; the self-regulating abscission of early-stage fruitlets lasts up to 8 weeks after full bloom and can result in the natural drop of 80 to 90% of the original flowers. Several approaches can be pursued to increase the fruit set, but in the present study, the focus was centered on A) alleviating the competition between young fruitlets during the early weeks of fruit development to reduce the loss by natural abscission and B) increasing the number of flower buds the following year. The study was set up in a 2018 planting of ‘WA 38’/G.935 orchard without hail-nets trained to V-trellis-system (4,975 trees/ha) in Central Washington (USA). The treatment consisted of the deployment, at early king bloom, of 80% reflective white material (RM, Extenday®) in the orchard inter-rows. The hypothesis relied upon the fact that enhanced light (mainly diffuse) could increase leaf C assimilation to support and nourish a higher proportion of fruitlets and decrease the natural abscission. The RM treatments had three different durations: reflective cover removed one month after installation (“RM for 1 M”), two months after (“RM for 2 M”) and until harvest (“RM until harvest”). They were compared against untreated control (“No RM (CTRL)”) in a 2-year trial. RM treatments did not result in a significant positive impact on fruit retention, net photosynthetic rate, yield, or return bloom. Trees subjected to whole-season RM had altered canopy and soil microclimates with drier and warmer canopies and cooler soil with higher moisture compared to untreated control. In the second season, a greater proportion of large apples (264-339 g or 72-64 apples/40-lb-box) was graded in RM until harvest treatment, indicating a positive influence of the enhanced light treatment in C allocation to fruit.

Delineating Molecular Regulatory of Flavonoids Indicated by Transcriptomic and Metabolomics Analysis during Flower Development in Chrysanthemum morifolium ‘Boju’

Flavonoids are pharmacologically active compounds in flowers of Chrysanthemum morifolium ‘Boju’ (C. morifolium); however, the molecular regulatory network governing flower development remains largely elusive. Flower samples were collected at four stages, namely budding (BD), bud breaking (BB), early blooming (EB), and full blooming (FB), for omics analysis. We revealed distinct transcriptional regulation patterns at these four stages of the flower from the perspective of differentially expressed unigenes (DEGs). There are 152 DEGs shared among the three comparative groups (BD vs. BB, BB vs EB, EB vs FB), wherein the expression of 44 DEGs (including AtADT6, MDL3, and ROMT) continues to be upregulated, and 85 DEGs (including CYP81E, TPS-Cin-1, and TPS-Cin-2) showed persistent downregulation with flower development. Flavonoid-targeted metabolomics identified 118 differentially abundant metabolites (DAMs) in the FB group compared to the BD stage; the top three upregulated and downregulated metabolites are Cyanidin-3-O-(6″-O-malonyl)glucoside-5-O-glucoside, Luteolin-7-O-(6″-caffeoyl)rhamnoside, Kaempferol-3-O-(6″-p-coumaroyl)glucoside and Chrysoeriol-6,8-di-C-glucoside-7-O-glucoside, Kaempferol, Kaempferol-3,7-O-dirhamnoside, respectively. These DAMs were predominantly enriched in “flavonoid biosynthesis”, “isoflavonoid biosynthesis”, and “flavone and flavonol biosynthesis” pathways. AtADT6, MDL3, ROMT, CYP81E, TPS-Cin-1, and TPS-Cin-2 were correlated with kaempferol. Our findings provide a new idea for interfering with flavonoid production, especially kaempferol, in flowers.

Oxidative weathering on the continent and seawater upwelling along the passive continental margin promoted widespread phosphorite formation at the Neoproterozoic-Cambrian boundary in South China

The latest Proterozoic to early Cambrian is characterized by major global phosphogenic events and the diversification of complex multicellular life. However, the feedback mechanism of atmospheric oxidation and upwelling processes to form voluminous phosphorite deposits is unclear. South China is a key example of the sedimentary spectrum related to the Neoproterozoic to Early Cambrian bloom of oxygenic photosynthesis, with alginite deposits (sapropelite; “stone coal”), barite, polymetallic black shales and phosphorites along the passive continental paleo-margin of the Yangtze craton. Here, we present a comprehensive geochemical analysis of drill core samples from the Zhijin phosphorite deposit, including Cr isotope, Fe speciation, and bulk elemental composition of dolostone, phosphorite and black shale from the Ediacaran to Early Cambrian sequence. The positively fractionated δ53Cr values of 0.11 to 1.81 ‰ of leachates from Ediacaran dolostone and Terreneuvian phosphorite indicate intensive oxidative terrestrial weathering. The phosphorite samples exhibit REE distribution patterns similar to modern seawater and strongly negative Ce anomalies (0.47–0.61), suggesting an oxic, open ocean environment. In contrast, the absence of Ce anomaly, high FeHR/FeT, and Fepy/FeHR ratios, enhanced redox-sensitive element concentrations, high Mo/TOC and TS/TOC, and high molar Corg:P ratios suggest euxinic to anoxic conditions for the overlying black shale sedimentation in a restricted sedimentary marine environment. Bulk-rock shale samples retain the positively fractionated Cr isotope pattern. The dramatic change from oxic to anoxic conditions aligns with the fossil record, which shows a proliferation of small shelly fossils in the phosphorite and their extinction in the overlying black shales, likely by hydrogen sulfide poisoning. We infer that nutrient-rich, oxidized upwelling seawater transported phosphorus and other nutrients to the photic zone, from where organic matter settled down to the seafloor and formed thick phosphorite beds at the oxic-anoxic boundary at and below the seafloor. Our study highlights that atmospheric and seawater oxygenation accelerated the Early Cambrian bio-diversification, and the subsequent restricted basin situation is responsible for the extinction at the Neoproterozoic-Cambrian boundary.

High and fine resolution of bloom dynamics using HPLC analysis in a semi-enclosed harbour

Chemotaxonomic analysis, a functionally efficient method, was performed every week over a year in the semi-enclosed Jangmok Bay to determine the composition of major phytoplankton assemblages, including small phytoplankton. Multiple blooms occurred through a year: two in summer and one in fall. The high abundance of diatoms in summer resulted in an intensive bloom of cryptophytes with a one-week time lag, followed by a dinoflagellate bloom in the fall. Additional microscopic analysis revealed an ecological succession of major phytoplankton species: a bloom of fast-growing Pseudo-nizschia sp. in summer was replaced by a bloom of Cryptomonas sp. one week after the diatom bloom, and then further succeeded to an Akashiwo sanguinea bloom in fall. The dominance of relatively small-sized Cryptomonas sp. led to a mismatch between the microscopic and chemotaxonomic results during the second bloom, indicating size dependence. In contrast, for the Akashiwo bloom, the microscope analysis was significantly underestimated by the chemotaxonomic analysis. Additionally, the ecological traits inherited by bloom-forming species play a role in their bloom dynamics. This study highlighted that the frequent sampling with the rapid HPLC analysis is effective for accurately understanding spatiotemporal variations of blooms, and can be an invaluable strategy for early warning and understanding bloom patterns in changing coastal ecosystems.

Mapping phenoregions and phytoplankton seasonality in Northeast Pacific marine coastal ecosystems via a satellite-based approach

Phytoplankton phenology describes yearly algal growth cycles and characterises the timing, duration, and magnitude of bloom occurrences. This study used satellite chlorophyll-a data from 1998 to 2020 and the Hierarchical Agglomerative Clustering method to define phenoregions based on phytoplankton phenology spatial patterns over the British Columbia and Southeast Alaska coastal oceans. The defined phenoregions were used to simplify the spatial complexity of the heterogenous study region and thus better describe phytoplankton seasonality across the target area. The cluster analysis allowed the delineation of four coherent regions: two coastal regions and northern and southern shelf/offshore regions. Results showed that each phenoregion had distinguishable phytoplankton phenological characteristics, likely due to different physical forcings acting in these areas. Moreover, the interannual variability of the spring bloom initiation was evaluated considering interactions between sea surface temperature (SST) anomalies and the El Niño Southern Oscillation Index (ENSO). Early spring blooms were associated with positive SST anomalies and El Niño conditions; conversely, average or late spring blooms occurred in years with negative SST anomalies and La Niña conditions, with the strongest relationship occurring in the southern shelf/offshore phenoregion. This study provided new insights into the regionalisation of the British Columbia and Southeast Alaska coastal oceans based on phytoplankton phenology patterns. Given the critical role of phytoplankton as the base of the marine food web, such phenoregions have implications for regional zooplankton biomass and fish production. The link between phytoplankton phenology and climate drivers points to the importance of environmental change in phytoplankton bloom dynamics. Further research into the connection between phytoplankton bloom indices and zooplankton community structure and production would be an important step towards using these indices for ecosystem monitoring and fisheries management.

Optimal growth conditions of the haptophyte Chrysochromulina leadbeateri causing massive fish mortality in Northern Norway

The haptophyte Chrysochromulina leadbeateri formed the most devastating fish-killing algal bloom ever recorded in Norway, in May and June 2019. The bloom resulted in the death of 14,500 tons of farmed salmon in Nordland and Troms Counties and large economic losses to the aquaculture industry in the region. Fish mortalities due to blooms of this species have occurred before in this region in 1991. Environmental conditions promoting bloom formation and growth of C. leadbeateri are, however, still poorly understood. Here we investigated growth as a function of temperature, salinity and irradiance in combinations using a high throughput experimental set-up. Three strains of C. leadbeateri isolated from the 2019 event and an earlier bloom in 1991 were examined. The highest maximal specific growth rate was found at salinities 28–30 and temperatures between 13 and 15 °C, with growth rate generally increasing with irradiance. The upper temperature tolerance for growth for all strains was at 17–19 °C. Further, analyses of the geographical distribution of C. leadbeateri in previous DNA-based studies compiled in the metaPR2 database revealed several ribotypes, and that a cold-water ribotype of C. leadbeateri caused both the 1991 and 2019 blooms.

Mastering Nature's Clock: Optimized Light Interruption Technique Propels Early Blooming and Record Yields in Chrysanthemum

Mastering Nature's Clock: Optimized Light Interruption Technique Propels Early Blooming and Record Yields in Chrysanthemum

Change of Forage Yield and Quality Characteristics of White Clover (Trifolium repens L.) at Different Harvest Time

This study was conducted to determine the yield and quality characteristics of white clover at different harvest time. The study was carried out according to the randomized blocks experimental design in 2021 and 2022, and the Rivendel variety of white clover was used as the plant material in the study. Four different harvest time of white clover, as early bloom, mid-bloom, full bloom, and after-bloom, were considered as the research subject. In the experiment, the plant height, green forage yield, dry matter yield, dry matter ratio, crude protein, crude protein yield, insoluble fiber in acid detergent (ADF), insoluble fiber in neutral detergent (NDF), relative feed value and phosphorus, potassium, calcium, and magnesium contents of white clover were investigated. It has been determined that the differences in all of these examined features in different harvest time of white clover were statistically significant. In the research, white clover reached the highest plant height (32.3 cm and 27.8 cm), green forage yield (38.367 kg ha-1 and 52.080 kg ha-1), dry matter yield (10.707 kg ha-1 and 13.424 kg ha-1), and crude protein yield (1987 kg ha-1 and 2544 kg ha-1) in full bloom in both years. In 2021, the highest crude protein and relative feed value and the lowest ADF and NDF ratios were obtained during early bloom and mid-bloom, while in 2022, the highest values for these characteristics were obtained only from early bloom stages. It was determined that the lowest phosphorus and potassium contents and the highest calcium and magnesium contents were obtained from the after bloom stage in both years. As a result, since the highest yield values and average quality values are obtained from the full bloom stage, it has been concluded that it was more advantageous for the producer to harvest the white clover at this stage.

The RNA-seq and BSA-seq analysis reveals genes associated to the control of early fruiting in walnut (Juglans regia L.)

Walnut is an important nut worldwide. The duration of the juvenile phase has a considerable impact on walnut yield. Floral transition is critical for walnut flowering and fruit setting. To improve walnut breeding, it is critical to study the mechanisms of early blooming and fruiting in early-fruiting (EF) walnuts and shorten their juvenile stages. This work used EF and later-fruiting (LF) walnuts to screen for genes associated with walnut early fruiting using RNA sequencing (RNA-seq) and bulk segregant analysis sequencing (BSA-seq). Thirty-seven key differential genes were analyzed using weighted gene co-expression network association (WGCNA) in RNA-seq, and FT, CAL, FUL, and APRR9 genes were found to be able to shorten the juvenile phase of plants by affecting the floral transition process and influencing plant fruiting time. BSA-seq was utilized to identify 3305656 SNPs and 596640 InDels in EF walnut and 925347 SNPs and 514751 InDels in LF walnut. A combined analysis of RNA-seq and BSA-seq revealed 49 structurally varied DEGs in both kinds, with 47 genes in the NC_049914.1 region, one gene in NC_049901.1, one gene locus in NC_049908.1, and eight structurally variant DEGs found solely in early fruiting walnuts. The analysis of candidate genes and verification of RT-qPCR expression revealed that JrLOC109015871 (JrPBL12), JrLOC108983551 (WRI1-like), JrLOC109016788 (WRKY12), and AP2-like genes are likely to be related to early fruiting of walnut, with WRKY12 being expressed at the highest level during the flowering peak of early fruiting walnut. It is likely that the WRKY12 gene regulates the flowering transition of walnut through the ageing pathway, allowing walnut to complete the transition from nutrient growth to reproductive growth more quickly and realize early fruiting to increase walnut yield, laying the groundwork for the study of the molecular mechanism of walnut's early fruiting trait.

Floral Response to Heat: A Study of Color and Biochemical Adaptations in Purple Chrysanthemums.

Chrysanthemums are among the world's most popular cut flowers, with their color being a key ornamental feature. The formation of these colors can be influenced by high temperatures. However, the regulatory mechanisms that control the fading of chrysanthemum flower color under high-temperature stress remain unclear. This study investigates the impact of high temperatures on the color and biochemical responses of purple chrysanthemums. Four purple chrysanthemum varieties were exposed to both normal and elevated temperature conditions. High-temperature stress elicited distinct responses among the purple chrysanthemum varieties. 'Zi Feng Che' and 'Chrystal Regal' maintained color stability, whereas 'Zi Hong Tuo Gui' and 'Zi lian' exhibited significant color fading, particularly during early bloom stages. This fading was associated with decreased enzymatic activities, specifically of chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS), indicating a critical period of color development under heat stress. Additionally, the color fading of 'Zi Lian' was closely related to the increased activity of the peroxidase (POD) and polyphenol oxidase (PPO). Conversely, a reduction in β-glucosidase (βG) activity may contribute significantly to the color steadfastness of 'Zi Feng Che'. The genes Cse_sc027584.1_g010.1 (PPO) and Cse_sc031727.1_g010.1 (POD) might contribute to the degradation of anthocyanins in the petals of 'Zi Hong Tuo Gui' and 'Zi Lian' under high-temperature conditions, while simultaneously maintaining the stability of anthocyanins in 'Zi Feng Che' and 'Chrystal Regal' at the early bloom floral stage. The findings of this research provide new insights into the physiological and biochemical mechanisms by which chrysanthemum flower color responds to high-temperature stress.

Comparison of imaging flow cytometry and microscopy for freshwater algal bloom detection

Gifford SR, St. Amand A, Graham JL, Foster GM, Sauve C, Clark D, Schroeder-Larkins H. 2024. Comparison of imaging flow cytometry and microscopy for freshwater algal bloom detection. Lake Reserv Manage. 40:221–235. Imaging flow cytometry (IFC) is an emerging tool that allows for rapid identification and enumeration of phytoplankton in freshwater systems. However, few studies have assessed the effects of preservation on IFC results or compared live IFC and microscopy results in freshwater systems. Understanding the effects of preservation and differences between IFC and microscopy will improve interpretation of these data and inform strategies to use IFC-based approaches in freshwater systems. Our study objectives were to compare IFC and phase contrast with epifluorescence microscopy as techniques for phytoplankton identification and enumeration, and the effects of sample preservation with an emphasis on taxa forming harmful cyanobacterial blooms (HCBs). During June through October 2020, samples were collected from 2 lakes in the Finger Lakes region of New York. Live and preserved samples were analyzed by laboratory-based IFC, and preserved samples were analyzed by microscopy. The IFC approach captured community dynamics while detecting potential cyanobacterial bloom-forming taxa earlier and at lower abundances than microscopy. Laboratory-based IFC allowed for an intermediate level of taxonomic information when compared to microscopy, gross techniques, such as extracted chlorophyll a or fluorescence sensors, and field-based operation of IFC approaches. The laboratory-based application of IFC in this study allowed receipt of results in 5 d or less, a substantial improvement over microscopy, which can be time-consuming to conduct. However, the laboratory-based IFC approach had some limitations. Imaging flow cytometry-estimated biovolume may be less accurate than microscopy for some taxa because of the algorithms used to calculate biovolume, particularly for chrysophytes and coccoid cyanobacteria. Colonial dissociation during preservation appeared to affect detection of Microcystis by IFC less than for other fragile bloom-forming taxa like chrysophytes. Our study results advance understanding of how IFC may translate to field-based approaches for early harmful algal bloom indicators in freshwater.

Ocean bottom-water oxygenation across the Late Miocene–Early Pliocene biogenic bloom

The Late Miocene–Early Pliocene biogenic bloom (ca. 9–3.5 millions of years ago, My) represents a period of globally heightened marine biological productivity. Paleoenvironmental studies across this interval show alternating phases of low-oxygen eutrophic and well-oxygenated oligotrophic conditions. Here, we focus on the bottom water oxygenation changes during the biogenic bloom to assess the validity of the enhanced Benthic Foraminifera Oxygen Index (EBFOI). The index was calculated for three ocean drilling sites: Ocean Drilling Program Site 1085 (southeast Atlantic), and International Ocean Discovery Program sites U1506 (southwest Pacific) and U1488 (equatorial Pacific). The quantitative study of benthic foraminiferal assemblages from Site 1488 allowed us to infer the paleoenvironmental evolution across the biogenic bloom. At this site, we document a shift from stable oxygen concentrations and seasonal input of phytodetritus (8.7–4.3 My) to short-term fluctuations between low oxygen eutrophic conditions and well-oxygenated oligotrophic conditions (4.3–3.0 My). The EBFOI calculated at sites 1085 and U1506 was cross-referenced with the published paleoenvironmental conditions. While the EBFOI proves to be a valuable tool to infer paleoenvironmental changes at the seafloor, it has limitations, as evidenced by comparisons with paleoenvironmental interpretations of Site U1488, where it does not consistently align with inferred oxygen conditions.

Exudates of Microcystis aeruginosa on oxidative stress and inflammatory responses in gills of Sinocyclocheilus grahami

Early cyanobacterial blooms studies observed that exposure to blue-green algae led to fish gills impairment. The objective of this work was to evaluate the toxic mechanisms of exudates of Microcystis aeruginosa (MaE) on fish gills. In this study, the toxic mechanism of MaE (2×106 cells/mL) and one of its main components phytosphingosine (PHS) with two concentrations 2.9 ng/mL and 145 ng/mL were conducted by integrating histopathology, biochemical biomarkers, and transcriptomics techniques in Sinocyclocheilus grahami (S. grahami) for 96 h exposure. Damaged gill tissue with epithelial hyperplasia and hypertrophy, remarkable Na+/K+-ATPase (NKA) enzyme activity, disrupted the redox homeostats including lipid peroxidation and inflammatory responses were observed in the fish of MaE exposure group. Compare to MaE exposure, two concentrations of PHS exposure appeared to be a trend of lower degree of tissue damage, NKA activity and oxidative stress, but induced obviously lipid metabolism disorder with higher triglycerides, total cholesterol and total bile acid, which might be responsible for inflammation responses in fish gill. By transcriptome analysis, MaE exposure were primarily enriched in pathways related to gill function and immune response. PHS exposure, with higher number of differentially expressed genes (DEGs), were enriched in Toll-like receptor (TLR), Mitogen-Activated Protein Kinase (MAPK) and NOD-like receptor protein 3 (NLRP3) pathways. We concluded that MaE and PHS were induced the inflammatory responses, with oxidative stress-induced inflammation for MaE exposure but lipid metabolism disorder-induced inflammation for PHS exposure. The present study provided two toxin-induced gill inflammation response pathways under cyanobacterial blooms, which could be a scientific basis for the ecological and health risk assessment in the aquatic environment.

Extreme heat exposure of host plants indirectly reduces solitary bee fecundity and survival.

Extreme heat poses a major threat to plants and pollinators, yet the indirect consequences of heat stress are not well understood, particularly for native solitary bees. To determine how brief exposure of extreme heat to flowering plants affects bee behaviour, fecundity, development and survival we conducted a no-choice field cage experiment in which Osmia lignaria were provided blueberry (Vaccinium corymbosum), phacelia (Phacelia tanacetifolia) and white clover (Trifolium repens) that had been previously exposed to either extreme heat (37.5°C) or normal temperatures (25°C) for 4 h during early bloom. Despite a similar number of open flowers and floral visitation frequency between the two treatments, female bees provided with heat-stressed plants laid approximately 70% fewer eggs than females provided with non-stressed plants. Their progeny received similar quantities of pollen provisions between the two treatments, yet larvae consuming pollen from heat-stressed plants had significantly lower survival as larvae and adults. We also observed trends for delayed emergence and reduced adult longevity when larvae consumed heat-stressed pollen. This study is the first to document how short, field-realistic bursts of extreme heat exposure to flowering host plants can indirectly affect bee pollinators and their offspring, with important implications for crop pollination and native bee populations.

On-farm harvest timing effects on alfalfa weevil across the Intermountain West region of the United States.

Alfalfa (Medicago sativa L.) is an economically important commodity in the Intermountain Western United States. A major concern for alfalfa producers in this region is the alfalfa weevil (Hypera postica Gyllenhal). Insecticide resistance development coupled with regulatory changes in pesticide use has resulted in renewed interest by producers in non-chemical control methods such as cultural control. One such cultural control method is early harvest, which consists of producers timing their harvests early in the season to decrease alfalfa weevil damage. This method is thought to be effective by exposing weevil larvae to adverse conditions before significant damage occurs. Still, early harvest can be difficult to employ because recommendations are often vague. To better understand how early harvest impacts both alfalfa weevils and their natural enemies and how producers are using this method across the Intermountain Western United States, we conducted a study in alfalfa production fields in Colorado, Montana, and Wyoming over three growing seasons. We determined that the timing of the initial alfalfa harvest spanned more than 1 month across fields, and alfalfa plant stage at harvest ranged from late vegetative to early bloom. Harvest was more impactful on reducing alfalfa weevil densities the earlier it was implemented. Removing windrows in a timely manner is likely useful to further decrease alfalfa weevil densities. Harvest timing was not associated with parasitism rates of alfalfa weevil, but higher parasitism rates were associated with lower post-harvest alfalfa weevil densities. This work has increased our understanding of early harvest in an on-farm setting and to improve recommendations for producers across the Intermountain Western United States.

Mutations overlying the miR172 target site of TOE-type genes are prime candidate variants for the double-flower trait in mei

Mutations affecting flower shape in many plants have been favored by human selection, and various fruit trees are also grown for ornamental purposes. Mei (Prunus mume) is a dual purpose tree originated in China well known in the Western world for its generous early blooms, often bearing double flowers. Building on the knowledge of its genomic location, a candidate gene approach was used to identify a 49 bp deletion encompassing the miR172 target site of the euAP2 gene pmTOE (PmuVar_Ch1_3490) as a prime variant linked to flower doubleness. Searching within a large dataset of genome sequencing data from Eastern germplasm collections demonstrated a tight variant-trait association, further confirmed in a panel of commercial and non-commercial varieties available in Italy. Moreover, two SNP mutations in the miR172 target site of pmPET (PmuVar_Ch1_1333) were identified in some double flower accessions. The mei orthologue of PETALOSA genes already found responsible for the phenotype in other plants suggests that independent variants may have been selected throughout mei domestication history.