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Science (New York, N.Y.) Jan 2022Fertilization of an egg by multiple sperm (polyspermy) leads to lethal genome imbalance and chromosome segregation defects. In , the block to polyspermy is facilitated...
Fertilization of an egg by multiple sperm (polyspermy) leads to lethal genome imbalance and chromosome segregation defects. In , the block to polyspermy is facilitated by a mechanism that prevents polytubey (the arrival of multiple pollen tubes to one ovule). We show here that FERONIA, ANJEA, and HERCULES RECEPTOR KINASE 1 receptor-like kinases located at the septum interact with pollen tube-specific RALF6, 7, 16, 36, and 37 peptide ligands to establish this polytubey block. The same combination of RALF (rapid alkalinization factor) peptides and receptor complexes controls pollen tube reception and rupture inside the targeted ovule. Pollen tube rupture releases the polytubey block at the septum, which allows the emergence of secondary pollen tubes upon fertilization failure. Thus, orchestrated steps in the fertilization process in are coordinated by the same signaling components to guarantee and optimize reproductive success.
Topics: Arabidopsis; Arabidopsis Proteins; Fertilization; Ligands; Ovule; Peptides; Phosphotransferases; Pollen; Pollen Tube; Pollination; Protein Kinases; Signal Transduction
PubMed: 35050671
DOI: 10.1126/science.abl4683 -
Current Opinion in Allergy and Clinical... Feb 2015The aim of the present review was to discuss the effects of pollen components on innate immune responses. (Review)
Review
PURPOSE OF REVIEW
The aim of the present review was to discuss the effects of pollen components on innate immune responses.
RECENT FINDINGS
Pollens contain numerous factors that can stimulate an innate immune response. These include intrinsic factors in pollens such as nicotinamide adenine dinucleotide phosphate oxidases, proteases, aqueous pollen proteins, lipids, and antigens. Each component stimulates innate immune response in a different manner. Pollen nicotinamide adenine dinucleotide phosphate oxidases induce reactive oxygen species generation and recruit neutrophils that stimulate subsequent allergic inflammation. Pollen proteases damage epithelial barrier function and increase antigen uptake. Aqueous pollen extract proteins and pollen lipids modulate dendritic cell function and induce Th2 polarization. Clinical studies have shown that modulation of innate immune response to pollens with toll-like receptor 9- and toll-like receptor 4-stimulating conjugates is well tolerated and induces clear immunological effects, but is not very effective in suppressing primary clinical endpoints of allergic inflammation.
SUMMARY
Additional research on innate immune pathways induced by pollen components is required to develop novel strategies that will mitigate the development of allergic inflammation.
Topics: Animals; Antigens, Plant; Humans; Immunity, Innate; NADH, NADPH Oxidoreductases; Neutrophils; Pollen; Reactive Oxygen Species; Rhinitis, Allergic, Seasonal; Th2 Cells
PubMed: 25546327
DOI: 10.1097/ACI.0000000000000136 -
Molecular Plant Jun 2022Haploid induction (HI) is an important tool in crop breeding. Phospholipase A1 (ZmPLA1)/NOT LIKE DAD (NLD)/MATRILINEAL (MTL) is a key gene controlling HI in maize;...
Haploid induction (HI) is an important tool in crop breeding. Phospholipase A1 (ZmPLA1)/NOT LIKE DAD (NLD)/MATRILINEAL (MTL) is a key gene controlling HI in maize; however, the underlying molecular mechanism remains unclear. In this study, to dissect why loss of ZmPLA1 function could mediate HI we performed a comprehensive multiple omics analysis of zmpla1 mutant anthers by integrating transcriptome, metabolome, quantitative proteome, and protein modification data. Functional classes of significantly enriched or differentially abundant molecular entities were found to be associated with the oxidative stress response, suggesting that a reactive oxygen species (ROS) burst plays a critical role in HI. In support of this, we further discovered that a simple chemical treatment of pollen with ROS reagents could lead to HI. Moreover, we identified ZmPOD65, which encodes a sperm-specific peroxidase, as a new gene controlling HI. Taken together, our study revealed a likely mechanism of HI, discovered a new gene controlling HI, and created a new method for HI in maize, indicating the importance of ROS balance in maintaining normal reproduction and providing a potential route to accelerate crop breeding.
Topics: Haploidy; Plant Breeding; Pollen; Reactive Oxygen Species; Zea mays
PubMed: 35395409
DOI: 10.1016/j.molp.2022.04.001 -
Current Opinion in Insect Science Apr 2021Microbes (fungi, bacteria and viruses) living within flowers are hypothesized to affect pollination. We evaluate current support for this idea at each stage of the... (Review)
Review
Microbes (fungi, bacteria and viruses) living within flowers are hypothesized to affect pollination. We evaluate current support for this idea at each stage of the pollination process. Evidence to date is convincing that microbes influence pollinator attraction, but data are heavily weighted toward bumblebees and the effects of nectar yeasts. Effects of microbes on the efficacy of pollinator visits is understudied and variable outcomes from field studies suggest quality of pollinator visits, not only quantity, are likely involved. The effect of microbes on pollen performance is underappreciated. Beyond the effect of pathogenic viruses, the impacts of pollen-transmitted endophytic microbes on pollen viability or tube growth are unknown but could affect the outcome of pollen receipt. Future research integrating microbes into pollination should broaden taxonomic diversity of microbes, pollinators and plants and the processes under study.
Topics: Animals; Behavior, Animal; Endophytes; Flowers; Host-Pathogen Interactions; Pollen; Pollination
PubMed: 33248285
DOI: 10.1016/j.cois.2020.11.002 -
The International Journal of... 2020Professor Panchanan Maheshwari served as Professor and Head of the Department of Botany, University of Delhi, from 1950 to 1966 and built an internationally reputed... (Review)
Review
Professor Panchanan Maheshwari served as Professor and Head of the Department of Botany, University of Delhi, from 1950 to 1966 and built an internationally reputed School of integrated plant embryology. Studies carried out during and after Maheshwari's period from this School have enormously advanced our knowledge of the structural, developmental and functional aspects of embryological processes. This review covers studies carried out at the Delhi School on the developmental biology of dispersed pollen grains which operate from pollen dispersal from the anthers until pollen tubes discharge the male gametes in the embryo sac for fertilization. These events include pollen viability and vigour, pollen germination and pollen tube growth, structural details of the pistil relevant to pollen function, pollination and pollen-pistil interaction.
Topics: Developmental Biology; Flowers; Gene Expression Regulation, Plant; Germination; Plant Proteins; Pollen; Pollen Tube
PubMed: 32659021
DOI: 10.1387/ijdb.190166ks -
The Science of the Total Environment Dec 2023Aeroallergens or inhalant allergens, are proteins dispersed through the air and have the potential to induce allergic conditions such as rhinitis, conjunctivitis, and... (Review)
Review
Aeroallergens or inhalant allergens, are proteins dispersed through the air and have the potential to induce allergic conditions such as rhinitis, conjunctivitis, and asthma. Outdoor aeroallergens are found predominantly in pollen grains and fungal spores, which are allergen carriers. Aeroallergens from pollen and fungi have seasonal emission patterns that correlate with plant pollination and fungal sporulation and are strongly associated with atmospheric weather conditions. They are released when allergen carriers come in contact with the respiratory system, e.g. the nasal mucosa. In addition, due to the rupture of allergen carriers, airborne allergen molecules may be released directly into the air in the form of micronic and submicronic particles (cytoplasmic debris, cell wall fragments, droplets etc.) or adhered onto other airborne particulate matter. Therefore, aeroallergen detection strategies must consider, in addition to the allergen carriers, the allergen molecules themselves. This review article aims to present the current knowledge on inhalant allergens in the outdoor environment, their structure, localization, and factors affecting their production, transformation, release or degradation. In addition, methods for collecting and quantifying aeroallergens are listed and thoroughly discussed. Finally, the knowledge gaps, challenges and implications associated with aeroallergen analysis are described.
Topics: Allergens; Pollen; Asthma; Particulate Matter; Europe; Air Pollutants
PubMed: 37709071
DOI: 10.1016/j.scitotenv.2023.167042 -
Journal of Oleo Science Sep 2018During ancient times in China, bee pollen was used for skin whitening and beauty. Around 70% of substances in bee pollen are biologically active, such as proteins,... (Review)
Review
During ancient times in China, bee pollen was used for skin whitening and beauty. Around 70% of substances in bee pollen are biologically active, such as proteins, carbohydrates, lipids and fatty acids, phenolic compounds, vitamins and bioelements.This review describes the cosmeceutical properties of bee pollen and the mechanism of its active components action, its beneficial influence on human skin. As a natural bee product, bee pollen may effectively enhance protective mechanisms against skin aging, skin dryness, ultraviolet B radiation, oxidative damage, inflammatory and melanogenesis, which are involved in a wide range of negative effects on human skin, thus they have attracted attention for health and cosmetic applications.
Topics: Amino Acids; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Antineoplastic Agents, Phytogenic; Antioxidants; Bees; Carbohydrates; Cosmetics; Humans; Lipids; Phytochemicals; Plant Proteins; Pollen; Polyphenols; Vitamins
PubMed: 30111679
DOI: 10.5650/jos.ess18048 -
Plant Reproduction Jun 2015Overview of pollen transcriptome studies. Pollen development is driven by gene expression, and knowledge of the molecular events underlying this process has undergone a... (Review)
Review
Overview of pollen transcriptome studies. Pollen development is driven by gene expression, and knowledge of the molecular events underlying this process has undergone a quantum leap in the last decade through studies of the transcriptome. Here, we outline historical evidence for male haploid gene expression and review the wealth of pollen transcriptome data now available. Knowledge of the transcriptional capacity of pollen has progressed from genetic studies to the direct analysis of RNA and from gene-by-gene studies to analyses on a genomic scale. Microarray and/or RNA-seq data can now be accessed for all phases and cell types of developing pollen encompassing 10 different angiosperms. These growing resources have accelerated research and will undoubtedly inspire new directions and the application of system-based research into the mechanisms that govern the development, function and evolution of angiosperm pollen.
Topics: Gene Expression Regulation, Plant; Plant Proteins; Plants; Pollen; Transcriptome
PubMed: 25761645
DOI: 10.1007/s00497-015-0261-7 -
Annals of Botany Jan 2019The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This... (Review)
Review
BACKGROUND
The male fitness pathway, from pollen production to ovule fertilization, is thought to strongly influence reproductive trait evolution in animal-pollinated plants. This pathway is characterized by multiple avenues of pollen loss which may lead to reductions in male fitness. However, empirical data on the mechanistic processes leading to pollen loss during transport are limited, and we therefore lack a comprehensive understanding of how male fitness is influenced by each step in the pollination process.
SCOPE
This review assesses the history of studying male function in plants and identifies critical gaps in our understanding of the ecology and evolution of pollen transport. We explore male reproductive function along the steps of the pathway to paternity and discuss evolutionary options to overcome barriers to siring success. In particular, we present a newly emerging idea that bodies of pollinators function as a dynamic arena facilitating intense male-male competition, where pollen of rival males is constantly covered or displaced by competitors. This perspective extends the pollen-competitive arena beyond the confines of the stigma and style, and highlights the opportunity for important new breakthroughs in the study of male reproductive strategies and floral evolution.
Topics: Animals; Magnoliopsida; Pollen; Pollination
PubMed: 30535041
DOI: 10.1093/aob/mcy167 -
The New Phytologist Aug 2014Pollen grains are microscopic so their identification and quantification has, for decades, depended upon human observers using light microscopes: a labour-intensive... (Review)
Review
Pollen grains are microscopic so their identification and quantification has, for decades, depended upon human observers using light microscopes: a labour-intensive approach. Modern improvements in computing and imaging hardware and software now bring automation of pollen analyses within reach. In this paper, we provide the first review in over 15 yr of progress towards automation of the part of palynology concerned with counting and classifying pollen, bringing together literature published from a wide spectrum of sources. We consider which attempts offer the most potential for an automated palynology system for universal application across all fields of research concerned with pollen classification and counting. We discuss what is required to make the datasets of these automated systems as acceptable as those produced by human palynologists, and present suggestions for how automation will generate novel approaches to counting and classifying pollen that have hitherto been unthinkable.
Topics: Automation; Botany; Pollen; Reference Standards
PubMed: 25180326
DOI: 10.1111/nph.12848