-
Metabolomics : Official Journal of the... Sep 2019Significant annual honey bee colony losses have been reported in the USA and across the world over the past years. Malnutrition is one among several causative factors...
BACKGROUND
Significant annual honey bee colony losses have been reported in the USA and across the world over the past years. Malnutrition is one among several causative factors for such declines. Optimal nutrition serves as the first line of defense against multiple stressors such as parasites/pathogens and pesticides. Given the importance of nutrition, it is imperative to understand bee nutrition holistically, identifying dietary sources that may fulfill bee nutritional needs. Pollen is the primary source of protein for bees and is critical for brood rearing and colony growth. Currently, there is significant gap in knowledge regarding the chemical and nutritional composition of pollen.
METHODS
Targeted sterol analysis and untargeted metabolomics were conducted on five commercially available crop pollens, three bee-collected crop pollens, three vegetable oils (often added to artificial protein supplements by beekeepers), and one commonly used artificial protein supplement.
RESULTS
This study reports key phytosterols and metabolites present across a spectrum of bee diets, including some of the major bee-pollinated crop pollens in the western United States. Significant differences were observed in sterol concentrations among the dietary sources tested. Among all quantified sterols, the highest concentrations were observed for 24-methylenecholesterol and further, pollen samples exhibited the highest 24-methylenecholesterol among all diet sources that were tested. Also, 236 metabolites were identified across all dietary sources examined.
CONCLUSION
Information gleaned from this study is crucial in understanding the nutritional landscape available to all bee pollinators and may further assist in future efforts to develop comprehensive database of nutrients and metabolites present in all bee diets.
Topics: Animals; Bees; Diet; Metabolomics; Phytosterols; Pollen
PubMed: 31538263
DOI: 10.1007/s11306-019-1590-6 -
Plant Cell Reports Feb 2022Fast-drying and cooling induce fast intracellular water loss and reduced ice-crystal formation, which may promote the formation of intracellular glasses that might...
Fast-drying and cooling induce fast intracellular water loss and reduced ice-crystal formation, which may promote the formation of intracellular glasses that might improve the likelihood of wheat pollen survival. Long-term storage of pollen is important for the fertilization of spatially or temporally isolated female parents, especially in hybrid breeding. Wheat pollen is dehydration-sensitive and rapidly loses viability after shedding. To preserve wheat pollen, we hypothesized that fast-drying and cooling rates would increase the rate of intracellular water content (WC) removal, decrease intracellular ice-crystal formation, and increase viability after exposure to ultra-low temperatures. Therefore, we compared slow air-drying with fast-drying (dry air flow) and found significant correlations between pollen WC and viability (r = 0.92, P < 0.001); significant differences in WCs after specific drying times; and comparable viabilities after drying to specific WCs. Fast-drying to WCs at which ice melting events were not detected (ΔH = 0 J mg DW, < 0.28 mg HO mg DW) reduced pollen viability to 1.2 ± 1.0%, but when drying to 0.39 mg HO mg DW, some viable pollen was detected (39.4 ± 17.9%). Fast cooling (150 °C min) of fast-dried pollen to 0.91 ± 0.11 mg HO mg DW induced less and a delay of ice-crystal formation during cryomicroscopic-video-recordings compared to slow cooling (1 °C min), but viability was low (4.5-6.1%) and comparable between cooling rates. Our data support that the combination of fast-drying and cooling rates may enable the survival of wheat pollen likely due to (1) a reduction of the time pollen would be exposed to drying-related deleterious biochemical changes and (2) an inhibition of intracellular ice-crystal formation, but additional research is needed to obtain higher pollen survival after cooling.
Topics: Calorimetry, Differential Scanning; Cold Temperature; Cryoelectron Microscopy; Cryopreservation; Crystallization; Desiccation; Freeze Drying; Freezing; Ice; Pollen; Triticum
PubMed: 35099612
DOI: 10.1007/s00299-021-02819-w -
International Journal of Molecular... Nov 2019The lily (Lilium spp.) anther contains a lot of pollen. It is not known if lily pollen contains allergens, and therefore screening pollen allergy-related proteins and...
The lily (Lilium spp.) anther contains a lot of pollen. It is not known if lily pollen contains allergens, and therefore screening pollen allergy-related proteins and genes is necessary. The pollen development period of lily 'Siberia' was determined by microscope observation. Early mononuclear microspores and mature pollens were used as sequencing materials. The analysis of the pollen transcriptome identified differentially expressed genes (DEGs), e.g., Profilin, Phl p 7 (Polcalcin), Ole e 1, and Phl p 11, which are associated with pollen allergens. The proteome analysis positively verified a significant increase in pollen allergenic protein content. The expression levels of LoProfiilin and LoPolcalcin, annotated as allergen proteins, gradually increased in mature pollen. LoProfiilin and LoPolcalcin were cloned and their open reading frame lengths were 396 bp and 246 bp, which encoded 131 and 81 amino acids, respectively. Amino acid sequence and structure alignment indicated that the protein sequences of LoProfilin and LoPolcalcin were highly conserved. Subcellular localization analysis showed that LoProfilin protein was localized in the cell cytoplasm and nucleus. LoProfilin and LoPolcalcin were highly expressed in mature pollen at the transcriptional and protein levels. A tertiary structure prediction analysis identified LoProfilin and LoPolcalcin as potential allergens in lily pollen.
Topics: Allergens; Amino Acid Sequence; Antigens, Plant; Cell Nucleus; Cytoplasm; Gene Expression Regulation, Plant; Lilium; Plant Proteins; Pollen; Protein Structure, Secondary; Proteome; Sequence Alignment; Transcriptome
PubMed: 31771269
DOI: 10.3390/ijms20235892 -
Plant & Cell Physiology Jul 2020Pollen lipids are essential for sexual reproduction, but our current knowledge regarding lipid dynamics in growing pollen tubes is still very scarce. Here, we report...
Pollen lipids are essential for sexual reproduction, but our current knowledge regarding lipid dynamics in growing pollen tubes is still very scarce. Here, we report unique lipid composition and associated gene expression patterns during olive pollen germination. Up to 376 genes involved in the biosynthesis of all lipid classes, except suberin, cutin and lipopolysaccharides, are expressed in olive pollen. The fatty acid profile of olive pollen is markedly different compared with other plant organs. Triacylglycerol (TAG), containing mostly C12-C16 saturated fatty acids, constitutes the bulk of olive pollen lipids. These compounds are partially mobilized, and the released fatty acids enter the β-oxidation pathway to yield acetyl-CoA, which is converted into sugars through the glyoxylate cycle during the course of pollen germination. Our data suggest that fatty acids are synthesized de novo and incorporated into glycerolipids by the 'eukaryotic pathway' in elongating pollen tubes. Phosphatidic acid is synthesized de novo in the endomembrane system during pollen germination and seems to have a central role in pollen tube lipid metabolism. The coordinated action of fatty acid desaturases FAD2-3 and FAD3B might explain the increase in linoleic and alpha-linolenic acids observed in germinating pollen. Continuous synthesis of TAG by the action of diacylglycerol acyltransferase 1 (DGAT1) enzyme, but not phosphoplipid:diacylglycerol acyltransferase (PDAT), also seems plausible. All these data allow for a better understanding of lipid metabolism during the olive reproductive process, which can impact, in the future, on the increase in olive fruit yield and, therefore, olive oil production.
Topics: Fatty Acids; Gene Expression Profiling; Gene Expression Regulation, Plant; Germination; Glyoxylates; Lipid Metabolism; Olea; Pollen; Pollen Tube; Transcriptome
PubMed: 32384163
DOI: 10.1093/pcp/pcaa063 -
Annals of Botany Oct 2023Plants often use floral displays to attract mutualists and prevent antagonist attacks. Chemical displays detectable from a distance include attractive or repellent... (Review)
Review
BACKGROUND
Plants often use floral displays to attract mutualists and prevent antagonist attacks. Chemical displays detectable from a distance include attractive or repellent floral volatile organic compounds (FVOCs). Locally, visitors perceive contact chemicals including nutrients but also deterrent or toxic constituents of pollen and nectar. The FVOC and pollen chemical composition can vary intra- and interspecifically. For certain pollinator and florivore species, responses to these compounds are studied in specific plant systems, yet we lack a synthesis of general patterns comparing these two groups and insights into potential correlations between FVOC and pollen chemodiversity.
SCOPE
We reviewed how FVOCs and non-volatile floral chemical displays, i.e. pollen nutrients and toxins, vary in composition and affect the detection by and behaviour of insect visitors. Moreover, we used meta-analyses to evaluate the detection of and responses to FVOCs by pollinators vs. florivores within the same plant genera. We also tested whether the chemodiversity of FVOCs, pollen nutrients and toxins is correlated, hence mutually informative.
KEY RESULTS
According to available data, florivores could detect more FVOCs than pollinators. Frequently tested FVOCs were often reported as pollinator-attractive and florivore-repellent. Among FVOCs tested on both visitor groups, there was a higher number of attractive than repellent compounds. FVOC and pollen toxin richness were negatively correlated, indicating trade-offs, whereas a marginal positive correlation between the amount of pollen protein and toxin richness was observed.
CONCLUSIONS
Plants face critical trade-offs, because floral chemicals mediate similar information to both mutualists and antagonists, particularly through attractive FVOCs, with fewer repellent FVOCs. Furthermore, florivores might detect more FVOCs, whose richness is correlated with the chemical richness of rewards. Chemodiversity of FVOCs is potentially informative of reward traits. To gain a better understanding of the ecological processes shaping floral chemical displays, more research is needed on floral antagonists of diverse plant species and on the role of floral chemodiversity in visitor responses.
Topics: Animals; Pollination; Flowers; Plant Nectar; Insecta; Pollen; Volatile Organic Compounds
PubMed: 37220889
DOI: 10.1093/aob/mcad064 -
Sensors (Basel, Switzerland) Aug 2022Airborne pollen surveys provide information on various aspects of biodiversity and human health monitoring. Such surveys are typically conducted using the Burkard...
Airborne pollen surveys provide information on various aspects of biodiversity and human health monitoring. Such surveys are typically conducted using the Burkard Multi-Vial Cyclone Sampler, but have to be technically optimized for eDNA barcoding. We here developed and tested a new airborne pollen trap, especially suitable for autonomous eDNA-metabarcoding analyses, called the A1 volumetric air sampler. The trap can sample pollen in 24 different tubes with flexible intervals, allowing it to operate independently in the field for a certain amount of time. We compared the efficiency of the new A1 volumetric air sampler with another automated volumetric spore trap, the Burkard Multi-Vial Cyclone Sampler, which features shorter and fewer sampling intervals to evaluate the comparability of ambient pollen concentrations. In a sterile laboratory environment, we compared trap performances between the automated volumetric air samplers by using pure dry pollen of three species-, and -which differ both by exine ornamentation and pollen size. The traps had a standard suction flow rate of 16.5 L/min, and we counted the inhaled pollen microscopically after a predefined time interval. Our results showed that though we put three different pollen types in the same container, both the traps inhaled all the pollens in a statistically significant manner irrespective of their size. We found that, on average, both traps inhaled equal an number of pollens for each species. We did not detect any cross-contamination between tubes. We concluded that the A1 volumetric air sampler has the potential to be used for longer and more flexible sampling intervals in the wild, suitable for autonomous monitoring of eDNA pollen diversity.
Topics: Air Pollutants; Biodiversity; Environmental Monitoring; Humans; Pollen
PubMed: 36080967
DOI: 10.3390/s22176512 -
International Journal of Molecular... Mar 2018Most chrysanthemum cultivars are self-incompatible, so it is very difficult to create pure lines that are important in chrysanthemum breeding and theoretical studies. In...
Most chrysanthemum cultivars are self-incompatible, so it is very difficult to create pure lines that are important in chrysanthemum breeding and theoretical studies. In our previous study, we obtained a self-compatible chrysanthemum cultivar and its self-pollinated seed set was 56.50%. It was interesting that the seed set of its ten progenies ranged from 0% to 37.23%. Examination of the factors causing the differences in the seed set will lead to an improved understanding of chrysanthemum self-incompatibility, and provide valuable information for creating pure lines. Pollen morphology, pollen germination percentage, pistil receptivity and embryo development were investigated using the in vitro culture method, the paraffin section technique, scanning electron microscopy and transmission electron microscopy. Moreover, RNA sequencing and bioinformatics were applied to analyzing the transcriptomic profiles of mature stigmas and anthers. It was found that the self-pollinated seed set of "Q10-33-1①","Q10-33-1③","Q10-33-1④" and "Q10-33-1⑩" were 37.23%, 26.77%, 7.97% and 0%, respectively. The differences in fertility among four progenies were mainly attributable to differences in pollen germination percentage and pistil receptivity. Failure of the seed set in "Q10-33-1⑩" was possibly due to self-incompatibility. In the transcriptomic files, 22 potential stigma genes and 8 potential pollen genes were found out.
Topics: Chrysanthemum; Plant Infertility; Pollen; Pollination; Self-Incompatibility in Flowering Plants; Transcriptome
PubMed: 29533976
DOI: 10.3390/ijms19030832 -
PloS One 2018Pear (Pyrus bretschneideri) is characterized by being self-incompatible and dependent on cross-pollination to set fruit. Honeybee (Apis mellifera) is considered the most...
Pear (Pyrus bretschneideri) is characterized by being self-incompatible and dependent on cross-pollination to set fruit. Honeybee (Apis mellifera) is considered the most important pollinator of pear. Nevertheless, limited pollen transfer has been cited as the main cause of poor fruit set in many pear orchards. Here, we tested the following hypotheses: (i) colony manipulations increase the pollen collection tendency of honeybees and (ii) the proportion of pollen loads being returned to the hive is from the target plant. The technique reliably and rapidly estimates the pollination of honeybees tested under different colony manipulations: (1) using pollen trapping (PT); (2) PT with sugar syrup feeding (SS) (PTSS); (3) SS alone and (4) control without PT and SS. The results clearly show that the pollen collection of honeybees during the experiment was significantly affected (P < 0.05) by colony manipulations. The mean amount of pollen harvested daily was higher for PTSS (19.4 g) and PT (16.4 g) than for SS (12.85 g) and control (8.7 g) colonies. Therefore, PTSS was the most effective treatment for increasing pear pollen collection; other treatments such as PT and SS could also be useful. This study was important for determining how the behavior of honeybee colonies is shaped through colony manipulation to enhance pollen collection of less preferred pear flowers, which is critical when pollination is required.
Topics: Animals; Bees; Feeding Behavior; Flowers; Pollen; Pollination; Pyrus; Sugars
PubMed: 30208089
DOI: 10.1371/journal.pone.0203648 -
Plant, Cell & Environment Nov 2015Pea (Pisum sativum L.) is a major legume crop grown in a semi-arid climate in Western Canada, where heat stress affects pollination, seed set and yield. Seed set and pod...
Pea (Pisum sativum L.) is a major legume crop grown in a semi-arid climate in Western Canada, where heat stress affects pollination, seed set and yield. Seed set and pod growth characteristics, along with in vitro percentage pollen germination, pollen tube growth and pollen surface composition, were measured in two pea cultivars (CDC Golden and CDC Sage) subjected to five maximum temperature regimes ranging from 24 to 36 °C. Heat stress reduced percentage pollen germination, pollen tube length, pod length, seed number per pod, and the seed-ovule ratio. Percentage pollen germination of CDC Sage was greater than CDC Golden at 36 °C. No visible morphological differences in pollen grains or the pollen surface were observed between the heat and control-treated pea. However, pollen wall (intine) thickness increased due to heat stress. Mid-infrared attenuated total reflectance (MIR-ATR) spectra revealed that the chemical composition (lipid, proteins and carbohydrates) of each cultivar's pollen grains responded differently to heat stress. The lipid region of the pollen coat and exine of CDC Sage was more stable compared with CDC Golden at 36 °C. Secondary derivatives of ATR spectra indicated the presence of two lipid types, with different amounts present in pollen grains from each cultivar.
Topics: Germination; Heat-Shock Response; Lipid Metabolism; Pisum sativum; Pollen; Pollen Tube; Seeds
PubMed: 26081983
DOI: 10.1111/pce.12589 -
Iranian Journal of Allergy, Asthma, and... Jun 2021Airborne pollen is considered one of the causative agents of hay fever, allergic rhinitis, conjunctivitis, and asthma. We aimed to investigate airborne pollens in the...
Airborne pollen is considered one of the causative agents of hay fever, allergic rhinitis, conjunctivitis, and asthma. We aimed to investigate airborne pollens in the context of Shiraz located in the southwest of Iran and find their association with meteorological parameters. The survey was conducted from October 2017 to September 2018, using seven days of volumetric Burkard spore trap, located in the center of the city. A total of 5810 pollen grains/m3 belonging to 15 taxa were identified and recorded. Among them, 73.8% was the tree, while the grass, shrub, and weed constituted 13.56%, 3.5%, and 9.2% of total reported pollens, respectively. The major pollen types were Platanaceae (28.39%), Oleaceae (21.17%), Pinaceae (15.11%), Amaranthaceae (9.29%), and Brassicaceae (8.02%). A higher number of pollen counts and types were recorded in March, followed by September, while it was lower in May. Meteorological parameters were correlated with the monthly pollen counts. Wind speed was found to have a positive correlation with Platanaceae concentration. The significant correlation between pollen concentration and the temperature was positive for Poaceae, Amaranthaceae, and Plantaginaceae and negative for Rosaceae, Oleaceae, and Ulmaceae. Poaceae and Amaranthaceae were negatively correlated with humidity and positively with Rosaceae, Oleaceae, and Plantaginaceae. A negative correlation was found between rainfall and Poaceae and Amaranthaceae, while Plantaginaceae had a positive correlation with this parameter. The results of this study may be helpful for allergologists in the diagnosis and treatment of airborne allergic disorders due to pollen grains.
Topics: Air Pollutants; Allergens; Environmental Monitoring; Humans; Iran; Pollen; Rain; Rhinitis, Allergic, Seasonal; Risk Assessment; Risk Factors; Seasons; Temperature; Time Factors; Weather; Wind
PubMed: 34134451
DOI: 10.18502/ijaai.v20i3.6332