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Plant, Cell & Environment Oct 2019Fruit and seed crop production heavily relies on successful stigma pollination, pollen tube growth, and fertilization of female gametes. These processes depend on... (Review)
Review
Fruit and seed crop production heavily relies on successful stigma pollination, pollen tube growth, and fertilization of female gametes. These processes depend on production of viable pollen grains, a process sensitive to high-temperature stress. Therefore, rising global temperatures threaten worldwide crop production. Close observation of plant development shows that high-temperature stress causes morpho-anatomical changes in male reproductive tissues that contribute to reproductive failure. These changes include early tapetum degradation, anther indehiscence, and deformity of pollen grains, all of which are contributing factors to pollen fertility. At the molecular level, reactive oxygen species (ROS) accumulate when plants are subjected to high temperatures. ROS is a signalling molecule that can be beneficial or detrimental for plant cells depending on its balance with the endogenous cellular antioxidant system. Many metabolites have been linked with ROS over the years acting as direct scavengers or molecular stabilizers that promote antioxidant enzyme activity. This review highlights recent advances in research on anther and pollen development and how these might explain the aberrations seen during high-temperature stress; recent work on the role of nitrogen and carbon metabolites in anther and pollen development is discussed including their potential role at high temperature.
Topics: Antioxidants; Carbon; Fertility; Gene Expression Regulation, Plant; Germination; Heat-Shock Response; Hot Temperature; Metabolome; Nitrogen; Plant Development; Pollen; Pollination; Reactive Oxygen Species; Reproduction; Stress, Physiological; Temperature
PubMed: 31077385
DOI: 10.1111/pce.13576 -
Molecular Plant Jun 2022Mutation of the sperm-specific phospholipase A and treatment of pollen with reactive oxygen species (ROS) reagents lead to the induction of maize haploids. ZmPOD65, a...
Mutation of the sperm-specific phospholipase A and treatment of pollen with reactive oxygen species (ROS) reagents lead to the induction of maize haploids. ZmPOD65, a gene associated with sperm-specific ROS metabolism, also exhibits a haploidization effect.
Topics: Haploidy; Pollen; Reactive Oxygen Species; Zea mays
PubMed: 35633042
DOI: 10.1016/j.molp.2022.05.010 -
PloS One 2023The rice GA biosynthetic gene OsGA3ox1 has been proposed to regulate pollen development through the gametophytic manner, but cellular characterization of its mutant...
The rice GA biosynthetic gene OsGA3ox1 has been proposed to regulate pollen development through the gametophytic manner, but cellular characterization of its mutant pollen is lacking. In this study, three heterozygotic biallelic variants, "-3/-19", "-3/-2" and "-3/-10", each containing one null and one 3bp-deletion allele, were obtained by the CRISPR/Cas9 technique for the functional study of OsGA3ox1. The three homozygotes, "-19/-19", "-2/-2" and "-10/-10", derived from heterozygotic variants, did not affect the development of most vegetative and floral organs but showed a significant reduction in seed-setting rate and in pollen viability. Anatomic characterizations of these mutated osga3ox1 pollens revealed defects in starch granule accumulation and pollen wall development. Additional molecular characterization suggests that abnormal pollen development in the osga3ox1 mutants might be linked to the regulation of transcription factors OsGAMYB, OsTDR and OsbHLH142 during late pollen development. In brief, the rice GA3ox1 is a crucial gene that modulates pollen starch granule accumulation and pollen wall development at the gametophytic phase.
Topics: Oryza; Plant Proteins; Seeds; Pollen; Starch; Gene Expression Regulation, Plant
PubMed: 37812600
DOI: 10.1371/journal.pone.0292400 -
Toxins Jan 2019Due to its divergent chemical composition and good nutritional properties, pollen is not only important as a potential food supplement but also as a good substrate for... (Review)
Review
Due to its divergent chemical composition and good nutritional properties, pollen is not only important as a potential food supplement but also as a good substrate for the development of different microorganisms. Among such microorganisms, toxigenic fungi are extremely dangerous as they can synthesize mycotoxins as a part of their metabolic pathways. Furthermore, favorable conditions that enable the synthesis of mycotoxins (adequate temperature, relative humidity, pH, and a values) are found frequently during pollen collection and/or production process. Internationally, several different mycotoxins have been identified in pollen samples, with a noted predominance of aflatoxins, ochratoxins, fumonisins, zearalenone, deoxynivalenol, and T-2 toxin. Mycotoxins are, generally speaking, extremely harmful for humans and other mammals. Current EU legislation contains guidelines on the permissible content of this group of compounds, but without information pertaining to the content of mycotoxins in pollen. Currently only aflatoxins have been researched and discussed in the literature in regard to proposed limits. Therefore, the aim of this review is to give information about the presence of different mycotoxins in pollen samples collected all around the world, to propose possible aflatoxin contamination pathways, and to emphasize the importance of a regular mycotoxicological analysis of pollen. Furthermore, a suggestion is made regarding the legal regulation of pollen as a food supplement and the proposed tolerable limits for other mycotoxins.
Topics: Food Contamination; Fungi; Mycotoxins; Pollen
PubMed: 30678361
DOI: 10.3390/toxins11020064 -
Plant Reproduction Jun 2016Pollen development and stress. In angiosperms, pollen or pollen grain (male gametophyte) is a highly reduced two- or three-cell structure which plays a decisive role in... (Review)
Review
Pollen development and stress. In angiosperms, pollen or pollen grain (male gametophyte) is a highly reduced two- or three-cell structure which plays a decisive role in plant reproduction. Male gametophyte development takes place in anther locules where diploid sporophytic cells undergo meiotic division followed by two consecutive mitotic processes. A desiccated and metabolically quiescent form of mature pollen is released from the anther which lands on the stigma. Pollen tube growth takes place followed by double fertilization. Apart from its importance in sexual reproduction, pollen is also an interesting model system which integrates fundamental cellular processes like cell division, differentiation, fate determination, polar establishment, cell to cell recognition and communication. Recently, pollen functionality has been studied by multidisciplinary approaches which also include OMICS analyses like transcriptomics, proteomics and metabolomics. Here, we review recent advances in proteomics of pollen development and propose the process of developmental priming playing a key role to guard highly sensitive developmental processes.
Topics: Heat-Shock Response; Hot Temperature; Pollen; Proteomics; Stress, Physiological
PubMed: 27271282
DOI: 10.1007/s00497-016-0283-9 -
Journal of Integrative Plant Biology Nov 2015Pollen development is a critical step in plant development that is needed for successful breeding and seed formation. Manipulation of male fertility has proved a useful... (Review)
Review
Pollen development is a critical step in plant development that is needed for successful breeding and seed formation. Manipulation of male fertility has proved a useful trait for hybrid breeding and increased crop yield. However, although there is a good understanding developing of the molecular mechanisms of anther and pollen anther development in model species, such as Arabidopsis and rice, little is known about the equivalent processes in important crops. Nevertheless the onset of increased genomic information and genetic tools is facilitating translation of information from the models to crops, such as barley and wheat; this will enable increased understanding and manipulation of these pathways for agricultural improvement.
Topics: Biotechnology; Plant Development; Pollen; Synteny
PubMed: 26310290
DOI: 10.1111/jipb.12425 -
Biomolecules Jan 2020Pollen is recognized as an excellent dietary supplement for human nutrition, which is why it can be found in different forms on the market (granules, capsules, tablets,... (Review)
Review
Pollen is recognized as an excellent dietary supplement for human nutrition, which is why it can be found in different forms on the market (granules, capsules, tablets, pellets, and powders). But, the digestibility of pollen's nutrients is strongly affected by the presence of a pollen shell, which can decrease the bioavailability of nutrients by 50% and more. Since consumers have become more aware of the benefits of a healthy diet and the necessity to improve pollen digestibility, different pollen-based functional food products have been developed and extensive studies were done to estimate the beneficial effects of pollen-based feed on animal growth, health, and rigor mortise stage. Considering the positive effects of pollen nutrients and phytometabolites on human and animal health, the aim of this paper was to give an overview of recent achievements in the application of pollen in the formulation of functional food and animal diets. Special attention was paid to the effects of pollen's addition on the nutritional, functional, techno-functional, and sensory properties of the new formulated food products. Anti-nutritional properties of pollen were also discussed. This review points out the benefits of pollen addition to food and feed and the possible directions in the further development of functional food and feed for the wellbeing of everyone.
Topics: Animal Feed; Animals; Biological Availability; Diet; Dietary Supplements; Food Additives; Functional Food; Humans; Pollen
PubMed: 31948037
DOI: 10.3390/biom10010084 -
American Journal of Botany May 2019Optimal defense theory predicts that selection should drive plants to disproportionally allocate resources for herbivore defense to tissues with high fitness values....
PREMISE
Optimal defense theory predicts that selection should drive plants to disproportionally allocate resources for herbivore defense to tissues with high fitness values. Because pollen's primary role is the transport of gametes, plants may be expected to defend it from herbivory. However, for many animal-pollinated plants, pollen serves a secondary role as a pollinator reward. These dual roles may present a conflict between selection to defend pollen from herbivores and selection to reward pollinators. Here, we investigate whether pollen secondary chemistry in three pollen-rewarding Lupinus species better reflects the need to defend pollen or reward pollinators.
METHODS
Lupinus (Fabaceae) species are nectarless, pollen-rewarding, and produce defensive quinolizidine and/or piperidine alkaloids throughout their tissues. We used gas chromatography to identify and quantitate the alkaloids in four aboveground tissues (pollen, flower, leaf, stem) of three western North American lupines, L. argenteus, L. bakeri, and L. sulphureus, and compared alkaloid concentrations and composition among tissues within individuals.
RESULTS
In L. argenteus and L. sulphureus, pollen alkaloid concentrations were 11-35% of those found in other tissues. We detected no alkaloids in L. bakeri pollen, though they were present in other tissues. Alkaloid concentrations were not strongly correlated among tissues within individuals. We detected fewer alkaloids in pollen compared to other tissues, and pollen contained no unique alkaloids.
CONCLUSIONS
Our results are consistent with the hypothesis that, in these pollen-rewarding species, pollen secondary chemistry may reflect the need to attract and reward pollinators more than the need to defend pollen from herbivory.
Topics: Alkaloids; Chromatography, Gas; Flowers; Lupinus; Plant Leaves; Plant Stems; Pollen; Pollination
PubMed: 31046151
DOI: 10.1002/ajb2.1283 -
The Science of the Total Environment Jul 2023Grass pollen is a leading cause of allergy in many countries, particularly Europe. Although many elements of grass pollen production and dispersal are quite well... (Review)
Review
Grass pollen is a leading cause of allergy in many countries, particularly Europe. Although many elements of grass pollen production and dispersal are quite well researched, gaps still remain around the grass species that are predominant in the air and which of those are most likely to trigger allergy. In this comprehensive review we isolate the species aspect in grass pollen allergy by exploring the interdisciplinary interdependencies between plant ecology, public health, aerobiology, reproductive phenology and molecular ecology. We further identify current research gaps and provide open ended questions and recommendations for future research in an effort to focus the research community to develop novel strategies to combat grass pollen allergy. We emphasise the role of separating temperate and subtropical grasses, identified through divergence in evolutionary history, climate adaptations and flowering times. However, allergen cross-reactivity and the degree of IgE connectivity in sufferers between the two groups remains an area of active research. The importance of future research to identify allergen homology through biomolecular similarity and the connection to species taxonomy and practical implications of this to allergenicity is further emphasised. We also discuss the relevance of eDNA and molecular ecological techniques (DNA metabarcoding, qPCR and ELISA) as important tools in quantifying the connection between the biosphere with the atmosphere. By gaining more understanding of the connection between species-specific atmospheric eDNA and flowering phenology we will further elucidate the importance of species in releasing grass pollen and allergens to the atmosphere and their individual role in grass pollen allergy.
Topics: Rhinitis, Allergic, Seasonal; Pollen; Hypersensitivity; Allergens; Poaceae
PubMed: 37094678
DOI: 10.1016/j.scitotenv.2023.163661 -
International Journal of Molecular... Jan 2019Pollen is the male gametophyte of higher plants. Its major function is to deliver sperm cells to the ovule to ensure successful fertilization. During this process, many... (Review)
Review
Pollen is the male gametophyte of higher plants. Its major function is to deliver sperm cells to the ovule to ensure successful fertilization. During this process, many interactions occur among pollen tubes and pistil cells and tissues, and calcium ion (Ca) dynamics mediate these interactions among cells to ensure that pollen reaches the embryo sac. Although the precise functions of Ca dynamics in the cells are unknown, we can speculate about its roles on the basis of its spatial and temporal characteristics during these interactions. The results of many studies indicate that calcium is a critical element that is strongly related to pollen germination and pollen tube growth.
Topics: Calcium; Flowers; Germination; Plant Development; Plant Physiological Phenomena; Pollen; Pollen Tube
PubMed: 30669423
DOI: 10.3390/ijms20020420