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The New Phytologist Feb 2020Pollen plays two important roles in angiosperm reproduction, serving as a vehicle for the plant's male gametes, but also, in many species, as a lure for pollen-feeding...
Pollen plays two important roles in angiosperm reproduction, serving as a vehicle for the plant's male gametes, but also, in many species, as a lure for pollen-feeding animals. Despite being an important food source for many pollinators, pollen often contains compounds with known deterrent or toxic properties, as documented in a growing number of studies. Here we review these studies and discuss the role of pollen defensive compounds in the coevolutionary relationship between plants and bees, the preeminent consumers of pollen. Next, we evaluate three hypotheses that may explain the existence of defensive compounds in pollen. The pleiotropy hypothesis, which proposes that defensive compounds in pollen merely reflect physiological spillover from other plant tissues, is contradicted by evidence from several species. Although plants may experience selection to defend pollen against poor-quality pollinators, we also find only partial support for the protection-against-pollen-collection-hypothesis. Finally, pollen defences might protect pollen from colonisation by antagonistic microorganisms (antimicrobial hypothesis), although data to evaluate this idea are scarce. Further research on the effects of pollen defensive compounds on pollinators, pollen thieves, and pollen-colonising microbes will be needed to understand why many plants have chemically defended pollen, and the consequences of those defences for pollen consumers.
Topics: Animals; Anti-Infective Agents; Bees; Biological Evolution; Ecological and Environmental Phenomena; Models, Biological; Pollen
PubMed: 31569278
DOI: 10.1111/nph.16230 -
Scientific Data Oct 2023Pollen-based evidence of human presence is crucial for reconstructing human history. However, information on the morphology of pollen grains of global food plants and...
Pollen-based evidence of human presence is crucial for reconstructing human history. However, information on the morphology of pollen grains of global food plants and regional pollen-based human indicators is scattered in the literature, leading to the risk of overlooking important evidence of human presence. To address this issue, we first compiled a comprehensive overview of 354 major food plants worldwide, creating a paleoecology-friendly format that includes their family, vernacular name, earliest known use, environmental preference, and geographical region. Moreover, we identified the sources of illustrations of their pollen grains for 209 out of 273 different genera of globally relevant food plants in 10 selected pollen atlases. Secondly, we compiled all human indicators from pollen-based paleoecological literature in Latin America (based on 750 references), providing an overview of 212 single-pollen type indicators and identified 95 crucial combinations of pollen types as "human indices", and their corresponding references. Our review datasets aids in distilling human evidence from numerous fossil pollen records worldwide.
Topics: Humans; Fossils; Latin America; Plants, Edible; Pollen
PubMed: 37857627
DOI: 10.1038/s41597-023-02613-1 -
Journal of Plant Research Sep 2016L-Arabinose (L-Ara) is a plant-specific sugar accounting for 5-10 % of cell wall saccharides in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). L-Ara occurs... (Review)
Review
L-Arabinose (L-Ara) is a plant-specific sugar accounting for 5-10 % of cell wall saccharides in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). L-Ara occurs in pectic arabinan, rhamnogalacturonan II, arabinoxylan, arabinogalactan-protein (AGP), and extensin in the cell walls, as well as in glycosylated signaling peptides like CLAVATA3 and small glycoconjugates such as quercetin 3-O-arabinoside. This review focuses on recent advances towards understanding the generation of L-Ara and the metabolism of L-Ara-containing molecules in plants.
Topics: Arabinose; Models, Biological; Phylogeny; Plants; Pollen; Uridine Diphosphate
PubMed: 27220955
DOI: 10.1007/s10265-016-0834-z -
International Journal of Molecular... Jun 2017Pollen is one of the most common causes of allergy worldwide, making the study of their molecular composition crucial for the advancement of allergy research. Despite...
Pollen is one of the most common causes of allergy worldwide, making the study of their molecular composition crucial for the advancement of allergy research. Despite substantial efforts in this field, it is not yet clear why some plant pollens strongly provoke allergies while others do not. However, proteases and protease inhibitors from allergen sources are known to play an important role in the development of pollen allergies. In this study, we aim to uncover differences in the transcriptional pattern of proteases and protease inhibitors in and pollen as models for high and low allergenic potential, respectively. We applied RNA sequencing to and pollen. After de-novo assembly we derived general functional profiles of the protein coding transcripts. By utilization of domain based functional annotation we identified potential proteases and protease inhibitors and compared their expression in the two types of pollen. Functional profiles are highly similar between and pollen. Both pollen contain proteases and inhibitors from 53 and 7 Pfam families, respectively. Some of the members comprised within those families are implicated in facilitating allergen entry, while others are known allergens themselves. Our work revealed several candidate proteins which, with further investigation, represent exciting new leads in elucidating the process behind allergic sensitization.
Topics: Allergens; Antigens, Plant; Computational Biology; Gene Expression Profiling; High-Throughput Nucleotide Sequencing; Molecular Sequence Annotation; Peptide Hydrolases; Plant Proteins; Pollen; Protease Inhibitors; Rhinitis, Allergic, Seasonal; Transcriptome; Workflow
PubMed: 28587253
DOI: 10.3390/ijms18061199 -
Journal of Investigational Allergology... 2014The Amaranthaceae family is composed of about 180 genera and 2500 species. These common weeds have become increasingly relevant as triggers of allergy in the last few... (Review)
Review
The Amaranthaceae family is composed of about 180 genera and 2500 species. These common weeds have become increasingly relevant as triggers of allergy in the last few years, as they are able to rapidly colonize salty and arid soils in extensive desert areas. The genera Chenopodium, Salsola, and Amaranthus are the major sources of pollinosis from the Amaranthaceae family in southern Europe, western United States, and semidesert areas of Saudi Arabia, Kuwait, and Iran. In Spain, Salsola kali is one of the most relevant causes of pollinosis, together with olive and grasses. To date, 9Amaranthaceae pollen allergens from Chenopodium album, Salsola kali, and Amaranthus retroflexus have been described and are listed in the International Union of Immunological Societies allergen nomenclature database.The major allergens ofAmaranthaceae pollen belong to the pectin methylesterase, Ole e 1-like, and profilin panallergen families, whereas the minor allergens belong to the cobalamin- independent methionine synthase and polcalcin panallergen families. These relevant allergens have been characterized physicochemically, and immunologically at different levels. Recombinant forms, allergenic fusion recombinant proteins, and hypoallergenic derivatives of these allergens have been expressed in bacteria and yeast and compared with their natural proteins from pollen. In this review, we provide an extensive overview ofAmaranthaceae pollen allergens, focusing on their physicochemical, and immunological properties and on their clinical significance in allergic patients. We also review studies where these recombinant allergens and their hypoallergenic derivatives have been used in clinical diagnosis and their potential use in personalized therapy.
Topics: Allergens; Amaranthaceae; Humans; Mediterranean Region; Pollen; Rhinitis, Allergic, Seasonal
PubMed: 25668889
DOI: No ID Found -
International Journal of Molecular... Feb 2022Although pollen structure and morphology evolved toward the optimization of stability and fertilization efficiency, its performance is affected by harsh environmental... (Review)
Review
Although pollen structure and morphology evolved toward the optimization of stability and fertilization efficiency, its performance is affected by harsh environmental conditions, e.g., heat, cold, drought, pollutants, and other stressors. These phenomena are expected to increase in the coming years in relation to predicted environmental scenarios, contributing to a rapid increase in the interest of the scientific community in understanding the molecular and physiological responses implemented by male gametophyte to accomplish reproduction. Here, after a brief introduction summarizing the main events underlying pollen physiology with a focus on polyamine involvement in its development and germination, we review the main effects that environmental stresses can cause on pollen. We report the most relevant evidence in the literature underlying morphological, cytoskeletal, metabolic and signaling alterations involved in stress perception and response, focusing on the final stage of pollen life, i.e., from when it hydrates, to pollen tube growth and sperm cell transport, with these being the most sensitive to environmental changes. Finally, we hypothesize the molecular mechanisms through which polyamines, well-known molecules involved in plant development, stress response and adaptation, can exert a protective action against environmental stresses in pollen by decoding the essential steps and the intersection between polyamines and pollen tube growth mechanisms.
Topics: Fertility; Germination; Pollen Tube; Polyamines; Signal Transduction; Stress, Physiological
PubMed: 35163795
DOI: 10.3390/ijms23031874 -
Computational and Mathematical Methods... 2022The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of...
BACKGROUND
The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions.
METHODS
The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO, NO, CO, and O), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored.
RESULTS
Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO, NO, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora.
CONCLUSION
The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.
Topics: Adult; Air Pollutants; Allergens; Humans; Meteorological Concepts; Nitrogen Dioxide; Particulate Matter; Pollen; Retrospective Studies; Rhinitis, Allergic; Seasons
PubMed: 36203530
DOI: 10.1155/2022/4619693 -
International Archives of Allergy and... 2020Pollens are responsible for allergic rhinitis, conjunctivitis, and asthma. The incidence of these diseases, which have adversely impacted the social and professional... (Review)
Review
Pollens are responsible for allergic rhinitis, conjunctivitis, and asthma. The incidence of these diseases, which have adversely impacted the social and professional lives of people who are allergic to pollen, has tripled in the past 25 years. Official institutes, health care institutions, public interest groups, and mainstream news media provide people who are allergic to pollen with advice aimed at reducing their symptoms. The aim of this work was to provide an inventory of the prevention guidelines in the world and to evaluate their scientific relevance. A PubMed search was carried out using specific keywords. The scientific relevance of the recommendations was evaluated based on the publications disproving or confirming their merit. The guidelines issued by 12 countries in Europe, North America, and Australia were inventoried. The recommendations for avoidance were most often based on scientific data regarding their impact on pollen exposures, but they have not been clinically validated. Several studies provided additional details, however, that allowed the guidelines to be further substantiated. These guidelines have been adopted in numerous industrialized countries in the world, and they generally appear to be of relevance.
Topics: Allergens; Animals; Antigens, Plant; Evidence-Based Practice; France; Health Planning Guidelines; Humans; Patient Education as Topic; Pollen; Rhinitis, Allergic, Seasonal
PubMed: 32911472
DOI: 10.1159/000510313 -
TheScientificWorldJournal 2014Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of...
Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.). Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride) and IKI (iodine potassium iodide), were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r(2) = 0.0614 and r(2) = 0.0015, resp.). Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.
Topics: Cell Survival; Culture Media; Culture Techniques; Genotype; Germination; Iodine Compounds; Pollen; Prunus; Staining and Labeling; Sucrose; Tetrazolium Salts
PubMed: 25405230
DOI: 10.1155/2014/657123 -
Journal of Investigational Allergology... 2007The olive tree is grown in many parts of the world. Its germplasm is very broad, with 250 varieties in Spain alone. Variations in the ability of pollen to germinate have... (Review)
Review
The olive tree is grown in many parts of the world. Its germplasm is very broad, with 250 varieties in Spain alone. Variations in the ability of pollen to germinate have been studied in detail and show conspicuous differences between varieties. However, commercial olive pollen from cultivars whose origin is unknown is the material that is commonly used for clinical and biological studies. We aim to assess the putative heterogeneity of olive cultivars with regard to the presence of several pollen allergens and to determine whether these differences have biological and clinical relevance. Previous studies show that most allergens isolated and characterized to date are highly polymorphic. Olive cultivars display wide differences in the expression levels of many allergens and in the number and molecular characteristics of the allergen isoforms expressed. These differences are maintained over the years, and are intrinsic to the genetics of each cultivar. Such broad polymorphism seems to be involved in the physiology of the olive reproductive system, which might include the adaptation of the plant to different environmental conditions, the establishment of the compatibility system, and pollen performance. The differences in allergen composition in cultivars, particularly in the Ole e 1 allergen, are responsible for the important differences in the allergenic potency of the extracts. These findings could have a number of implications for the diagnosis and therapy of olive pollen allergy. We discuss how cultivar differences affect extract quality, diagnostic and therapeutic efficacy and safety, and the development of new vaccines based on the use of recombinant allergens.
Topics: Allergens; Humans; Olea; Pollen; Polymorphism, Genetic; Protein Isoforms; Rhinitis, Allergic, Seasonal; Spain
PubMed: 18050567
DOI: No ID Found