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Plant Science : An International... Feb 2015Magnesium is one of the essential macro-elements for plant growth and development, participated in photosynthesis and various metabolic processes. The Mg-transport...
Magnesium is one of the essential macro-elements for plant growth and development, participated in photosynthesis and various metabolic processes. The Mg-transport abilities of the AtMGT (Magnesium Transporter) genes were identified in bacteria or yeast mutant system. In our previous studies, both the AtMGT5 and AtMGT9 were found essential for pollen development in Arabidopsis. Here we report another AtMGT member, AtMGT4, which was localized to the endoplasmic reticulum, was essential for pollen development as well. AtMGT4 expressed notably in pollen grains from bicellular pollen stage to mature pollen stage. A T-DNA insertional mutant of the gene, named mgt4-1, showed pollen abortive phenotype, thus we could not get any homozygous mutant from progenies of self-crossed +/mgt4-1 plants. Meanwhile, nearly half of pollens in AtMGT4-RNAi transgenic lines were sterile, consistent with the phenotype of +/mgt4-1 mutant. Transgenic plants expressing AtMGT4 in the mgt4-1 background could recover the pollen fertility to the wild type. Together, our findings demonstrated that the disruption of AtMGT4 in Arabidopsis could cause a defect of pollen development. The visible pollen abortion appeared at bicellular pollen stage in +/mgt4-1.
Topics: Arabidopsis; Arabidopsis Proteins; Endoplasmic Reticulum; Gene Expression Regulation, Plant; Magnesium; Pollen
PubMed: 25576006
DOI: 10.1016/j.plantsci.2014.12.008 -
Annals of Botany Sep 2011S-RNase-based self-incompatibility (SI) occurs in the Solanaceae, Rosaceae and Plantaginaceae. In all three families, compatibility is controlled by a polymorphic... (Review)
Review
BACKGROUND
S-RNase-based self-incompatibility (SI) occurs in the Solanaceae, Rosaceae and Plantaginaceae. In all three families, compatibility is controlled by a polymorphic S-locus encoding at least two genes. S-RNases determine the specificity of pollen rejection in the pistil, and S-locus F-box proteins fulfill this function in pollen. S-RNases are thought to function as S-specific cytotoxins as well as recognition proteins. Thus, incompatibility results from the cytotoxic activity of S-RNase, while compatible pollen tubes evade S-RNase cytotoxicity.
SCOPE
The S-specificity determinants are known, but many questions remain. In this review, the genetics of SI are introduced and the characteristics of S-RNases and pollen F-box proteins are briefly described. A variety of modifier genes also required for SI are also reviewed. Mutations affecting compatibility in pollen are especially important for defining models of compatibility and incompatibility. In Solanaceae, pollen-side mutations causing breakdown in SI have been attributed to the heteroallelic pollen effect, but a mutation in Solanum chacoense may be an exception. This has been interpreted to mean that pollen incompatibility is the default condition unless the S-locus F-box protein confers resistance to S-RNase. In Prunus, however, S-locus F-box protein gene mutations clearly cause compatibility.
CONCLUSIONS
Two alternative mechanisms have been proposed to explain compatibility and incompatibility: compatibility is explained either as a result of either degradation of non-self S-RNase or by its compartmentalization so that it does not have access to the pollen tube cytoplasm. These models are not necessarily mutually exclusive, but each makes different predictions about whether pollen compatibility or incompatibility is the default. As more factors required for SI are identified and characterized, it will be possible to determine the role each process plays in S-RNase-based SI.
Topics: Genetic Loci; Models, Biological; Mutation; Pollen; Ribonucleases; Self-Incompatibility in Flowering Plants
PubMed: 21803740
DOI: 10.1093/aob/mcr179 -
Food Research International (Ottawa,... Nov 2021Sunflower pollen is a natural nutritious food with a long history and multiple functions, however, the main chemical components apart from flavonoids and their...
Sunflower pollen is a natural nutritious food with a long history and multiple functions, however, the main chemical components apart from flavonoids and their biosynthesis processes have not been thoroughly investigated. In this study, seven hydroxycinnamic acid amides (HCAAs) (1-7) abundant in sunflower pollen were isolated and identified as one type of the pollen's main chemicals. For a comprehensive understanding of HCAA biosynthesis in Helianthus annuus flowers, RNA-seq, metabolomics, and key genes related to biosynthesis in the sunflower were studied. A large number of compounds at different sunflower growth stages (the 7th, 14th, 21st, and 28th days) and high expression levels of related genes in the transcriptome were detected. A molecular network was constructed to clarify the synthetic pathway of HCAAs, which revealed high transcriptional levels of spermidine hydroxycinnamoyl transferase genes (HaSHT2795 and HaSHT2436) in 14-21-days-old flowers. HaSHT2795 enzymes catalyze tri-coumaroylspermidine formation, and virus-induced gene silencing to inhibit HaSHT2795 and HaSHT2436 could significantly reduce the synthesis of hydroxycinnamic acid amides in sunflower pollen. HCAAs were inferred to be related to the formation of pollen walls and the health effects of pollen. Analyzing HCAA biosynthesis and accumulation in H. annuus pollen will be helpful to understand the functions of HCAAs in the development of pollen and its nutritional value.
Topics: Amides; Coumaric Acids; Helianthus; Pollen; Transcriptome
PubMed: 34600680
DOI: 10.1016/j.foodres.2021.110678 -
PloS One 2013Loss of pollen-S function in Prunus self-compatible cultivars has been mostly associated with deletions or insertions in the S-haplotype-specific F-box (SFB) genes....
Loss of pollen-S function in Prunus self-compatible cultivars has been mostly associated with deletions or insertions in the S-haplotype-specific F-box (SFB) genes. However, self-compatible pollen-part mutants defective for non-S-locus factors have also been found, for instance, in the apricot (Prunus armeniaca) cv. 'Canino'. In the present study, we report the genetic and molecular analysis of another self-compatible apricot cv. termed 'Katy'. S-genotype of 'Katy' was determined as S(1)S(2) and S-RNase PCR-typing of selfing and outcrossing populations from 'Katy' showed that pollen gametes bearing either the S(1)- or the S(2)-haplotype were able to overcome self-incompatibility (SI) barriers. Sequence analyses showed no SNP or indel affecting the SFB(1) and SFB(2) alleles from 'Katy' and, moreover, no evidence of pollen-S duplication was found. As a whole, the obtained results are compatible with the hypothesis that the loss-of-function of a S-locus unlinked factor gametophytically expressed in pollen (M'-locus) leads to SI breakdown in 'Katy'. A mapping strategy based on segregation distortion loci mapped the M'-locus within an interval of 9.4 cM at the distal end of chr.3 corresponding to ∼1.29 Mb in the peach (Prunus persica) genome. Interestingly, pollen-part mutations (PPMs) causing self-compatibility (SC) in the apricot cvs. 'Canino' and 'Katy' are located within an overlapping region of ∼273 Kb in chr.3. No evidence is yet available to discern if they affect the same gene or not, but molecular markers seem to indicate that both cultivars are genetically unrelated suggesting that every PPM may have arisen independently. Further research will be necessary to reveal the precise nature of 'Katy' PPM, but fine-mapping already enables SC marker-assisted selection and paves the way for future positional cloning of the underlying gene.
Topics: Chromosome Mapping; Genetic Linkage; Genetic Loci; Genotype; Mutation; Open Reading Frames; Pollen; Prunus; Self-Incompatibility in Flowering Plants; Synteny
PubMed: 23342044
DOI: 10.1371/journal.pone.0053947 -
Revue Des Maladies Respiratoires Oct 2001
Topics: Allergens; Humans; Pollen; Respiratory Hypersensitivity
PubMed: 11887761
DOI: No ID Found -
Huan Jing Ke Xue= Huanjing Kexue Sep 2010Ambient particulate matters (PM) and allergenic pollens in urban atmosphere have taken negative effects on human health and air quality. Studies on synergistic effects... (Review)
Review
Ambient particulate matters (PM) and allergenic pollens in urban atmosphere have taken negative effects on human health and air quality. Studies on synergistic effects between the two pollutants are being focused in disciplines, such as atmospheric sciences, environmental toxicology, and immunology. In this study, physicochemical characterization of airborne fine/ultrafine particles in Shanghai, China and ambient allergenic pollens (cedar) in Kanto, Japan were investigated. We found that allergenic protein particles (Ubisch body) with diameter less than 0.7 microm were absorbed on Japanese cedar pollen, and airborne particles which contained allergenic particles mainly distributed in < 1 microm size range. The highest mass concentration of chemical elements in Shanghai airborne particles was found in the 0.3-0.18 microm size range, but mass level of pollutant elements, such as S and Pb, in ambient in ultrafine (nano) particles were higher than that in coarse and fine particles. And also, pollen particles were found in Shanghai airborne particles. Synergistic effects between diesel exhaust particles (DEPs), which were the main component in urban airborne particles, and ambient pollens in urban atmosphere can be found, but their mechanism have not been clear. After our new results and other conclusions published recently on allergenic pollen and airborne fine/ultrafine particles were summarized, perspectives of this new discipline were presented.
Topics: Air Pollutants; Animals; Atmosphere; Cities; Environmental Monitoring; Humans; Particle Size; Particulate Matter; Pollen; Rhinitis, Allergic, Seasonal; Vehicle Emissions
PubMed: 21072956
DOI: No ID Found -
The Journal of Allergy and Clinical... May 2003Pollen from early-flowering trees (eg, birch, alder, hazel) represent major seasonal allergen sources. The effects of rain on the release of allergens from tree pollen...
BACKGROUND
Pollen from early-flowering trees (eg, birch, alder, hazel) represent major seasonal allergen sources. The effects of rain on the release of allergens from tree pollen has thus far not been studied at the ultrastructural level.
OBJECTIVE
This study was designed to investigate the effects of rain on the morphology of pollens from early-flowering trees and of potential rain-induced mechanisms of allergen release.
METHODS
Freshly collected pollen grains (birch, alder, and hazel) were exposed under controlled conditions to rainwater. Changes of pollen morphology and the release of allergens were analyzed by scanning electron microscopy. The release of allergen-bearing submicronic particles was studied by field emission scanning electron microscopy and transmission electron microscopy in conjunction with immunogold staining by using antibodies with specificity for the major allergens.
RESULTS
Scanning electron microscopy showed that freshly isolated pollen grains from birch, alder, and hazel have abortive germination in rainwater. Abortive pollen germination is characterized by the formation of short pollen tubes, which rupture at their tips and release micronic and submicronic particles containing major allergens. Immunogold transmission electron microscopy provided evidence that the allergens are transported through the pollen tubes during germination.
CONCLUSIONS
Rainwater-induced release of allergen-bearing submicronic particles from abortively germinated tree pollens may represent a mechanism of allergen release, with important implications on the induction of asthma as well as on current methods for measuring environmental allergen exposure.
Topics: Allergens; Alnus; Betula; Germination; Microscopy, Immunoelectron; Pollen; Rain
PubMed: 12743566
DOI: 10.1067/mai.2003.1452 -
Methods in Cell Biology 1995
Review
Topics: Cell Culture Techniques; Cell Separation; Cytological Techniques; Pollen
PubMed: 8531769
DOI: 10.1016/s0091-679x(08)61466-1 -
Journal of Controlled Release :... Dec 2021Pollen is an excellent natural substance that plays an essential role in the reproduction of plants. In this review, we explain the structure, compositions, and... (Review)
Review
Pollen is an excellent natural substance that plays an essential role in the reproduction of plants. In this review, we explain the structure, compositions, and characteristics of pollens. We consider pollen as a multifunctional tool that can be used in therapeutic/diagnostic systems. This microcapsule can be used in the forms of the hollow microcapsule, microgel, and composite, and also can be a tool for the synthesis of micro/nanostructures in various medical applications and used for the production of genetically modified plants that affect human health. In addition, we investigate the capability of this multifunctional tool in the immune system targeting that acts as an immunomodulator. In all applications and capabilities, we explain the potential of using nanostructures as parts of these systems and as auxiliary tools for promoting the applications of pollen. It is expected that soon, with the help of pollen-based therapeutic/diagnostic systems with the ability to immune system targeting, we will achieve effective and targeted therapeutic systems for the treatment of inflammatory and autoimmune diseases. In this paper, we suggest some ideas that may be a new step for future researches.
Topics: Humans; Immune System; Nanostructures; Pollen
PubMed: 34763004
DOI: 10.1016/j.jconrel.2021.11.008 -
PloS One 2015Pollen is one of the primary causes of allergic rhinoconjunctivitis in urban centers. In the present study, the concentrations of 39 different pollens in the Santiago de...
Pollen is one of the primary causes of allergic rhinoconjunctivitis in urban centers. In the present study, the concentrations of 39 different pollens in the Santiago de Chile metropolitan area over the period 2009-2013 are characterized. The pollen was monitored daily using Burkard volumetric equipment. The contribution of each type of pollen and the corresponding time trends are evaluated. The concentrations of the pollens are compared with the established threshold levels for the protection of human health. The results show that the total amount of pollen grains originating from trees, grasses, weeds and indeterminate sources throughout the period of the study was 258,496 grains m-3, with an annual average of 51,699 ± 3,906 grains m-3 year-1. The primary source of pollen is Platanus orientalis, which produces 61.8% of the analyzed pollen. Grass pollen is the third primary component of the analyzed pollen, with a contribution of 5.82%. Among the weeds, the presence of Urticacea (3.74%) is remarkable. The pollination pattern of the trees is monophasic, and the grasses have a biphasic pattern. The trends indicate that the total pollen and tree pollen do not present a time trend that is statistically significant throughout the period of the study, whereas the grass pollen and weed pollen concentrations in the environment present a statistically significant decreasing trend. The cause of this decrease is unclear. The pollen load has doubled over the past decade. When the observed concentrations of the pollens were compared with the corresponding threshold levels, the results indicated that over the period of the study, the pollen concentrations were at moderate, high and very high levels for an average of 293 days per year. Systematic counts of the pollen grains are an essential method for diagnosing and treating patients with pollinosis and for developing forestation and urban planning strategies.
Topics: Air Pollutants; Allergens; Biodiversity; Chile; Cities; Poaceae; Pollen; Seasons; Trees
PubMed: 25946339
DOI: 10.1371/journal.pone.0123077