scholarly journals SYP72 interacts with the mechanosensitive channel MSL8 to protect pollen from hypoosmotic shock during hydration

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Xuemei Zhou ◽  
Yifan Zheng ◽  
Ling Wang ◽  
Haiming Li ◽  
Yingying Guo ◽  
...  
Keyword(s):  
Pollen Germination ◽  
Critical Role ◽  
Pollen Grains ◽  
Flowering Plants ◽  
Mechanosensitive Channel ◽  
Snare Protein ◽  
Pollen Hydration ◽  
Hypoosmotic Shock ◽  
Cellular Integrity ◽  
Mutant Pollen

AbstractIn flowering plants, hydration of desiccated pollen grains on stigma is a prerequisite for pollen germination, during which pollen increase markedly in volume through water uptake, requiring them to survive hypoosmotic shock to maintain cellular integrity. However, the mechanisms behind the adaptation of pollen to this hypoosmotic challenge are largely unknown. Here, we identify the Qc-SNARE protein SYP72, which is specifically expressed in male gametophytes, as a critical regulator of pollen survival upon hypoosmotic shock during hydration. SYP72 interacts with the MSCS-LIKE 8 (MSL8) and is required for its localization to the plasma membrane. Intraspecies and interspecies genetic complementation experiments reveal that SYP72 paralogs and orthologs from green algae to angiosperms display conserved molecular functions and rescue the defects of Arabidopsis syp72 mutant pollen facing hypoosmotic shock following hydration. Our findings demonstrate a critical role for SYP72 in pollen resistance to hypoosmotic shock through the MSL8 cascade during pollen hydration.

scholarly journals Arabidopsis ECERIFERUM3 (CER3) Plays a Critical Role in Maintaining Hydration for Pollen-Stigma Recognition during Fertilization

2019 ◽  
Author(s):  
Faqing Xu ◽  
Xiaojing Li ◽  
Zhongnan Yang ◽  
Sen Zhang
Keyword(s):  
Critical Role ◽  
Pollen Grains ◽  
Underlying Mechanism ◽  
Recognition System ◽  
Development Stage ◽  
Male Sterile ◽  
Foreign Pollen ◽  
Compatible Pollen ◽  
Mutant Pollen

ABSTRACTPlants distinguish the pollen grains that land on their stigmas, only allowing compatible pollen to fertilize female gametes. To analyze the underlying mechanism, conditional male-sterile mutations with affected pollen coat and disrupted pollen-stigma recognition were isolated and described. The mutant pollen failed to germinate, but germinated in vitro, suggesting that they are viable. In mutants, stigma cells that contacted their own pollen generated callose, a carbohydrate produced in response to foreign pollen. High humidity restored pollen hydration and successful fertilization, indicating defective dehydration in pollen-stigma interaction. Further analysis results from mixed pollination experiments demonstrated that the mutant pollen specifically lacked a functional pollen-stigma recognition system. The sterile plants lacked stem waxes and displayed postgenital fusion between aerial floral organs. In addition, the mutant pollen was deficient in long-chain lipids and had excess tryphine. Transmission electron microscopy observation showed that mutant pollen had almost the same surface structure as the wild type at bicellular pollen stage. However, abnormal plastoglobuli were observed in the plastids of the mutant tapetum, which was indicative of altered lipid accumulation. CER3 transcript was found in anther tapetum and microspores at development stage 9 while CER3-GFP fusion protein was localized to the cell plasma membrane. Our data reveal that CER3 is required for biosynthesis of tryphine lipids which play a critical role in maintaining hydration for pollen-stigma recognition during fertilization.

scholarly journals Pollen Germination and Pollen Tube Growth in Gymnosperms

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1301
Author(s):  
Maria Breygina ◽  
Ekaterina Klimenko ◽  
Olga Schekaleva
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Flowering Plants ◽  
Reproductive Physiology ◽  
Tube Growth ◽  
Seed Plants ◽  
Main Body ◽  
Physiological Studies

Pollen germination and pollen tube growth are common to all seed plants, but these processes first developed in gymnosperms and still serve for their successful sexual reproduction. The main body of data on the reproductive physiology, however, was obtained on flowering plants, and one should be careful to extrapolate the discovered patterns to gymnosperms. In recent years, physiological studies of coniferous pollen have been increasing, and both the features of this group and the similarities with flowering plants have already been identified. The main part of the review is devoted to physiological studies carried out on conifer pollen. The main properties and diversity of pollen grains and pollination strategies in gymnosperms are described.

scholarly journals Mitochondrien unter Stress: Die Rolle der Präsequenzprotease MPP

BIOspektrum ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 390-393
Author(s):  
F.-Nora Vögtle
Keyword(s):  
Stress Response ◽  
Cellular Stress ◽  
Critical Role ◽  
Mitochondrial Protein ◽  
Nuclear Genome ◽  
Cellular Stress Response ◽  
Mitochondrial Proteins ◽  
Protein Biogenesis ◽  
Cellular Integrity

AbstractThe majority of mitochondrial proteins are encoded in the nuclear genome, so that the nearly entire proteome is assembled by post-translational preprotein import from the cytosol. Proteomic imbalances are sensed and induce cellular stress response pathways to restore proteostasis. Here, the mitochondrial presequence protease MPP serves as example to illustrate the critical role of mitochondrial protein biogenesis and proteostasis on cellular integrity.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

scholarly journals Biology of Flowering, Fruit and Viability of Pollen of Varieties and Forms of Quince Cultivated on the Territory of the Nakhchivan Autonomous Republic

2021 ◽  
Vol 7 (3) ◽  
pp. 64-69
Author(s):  
L. Bayramov
Keyword(s):  
Pollen Fertility ◽  
Pollen Germination ◽  
Glucose Solution ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Weather Conditions ◽  
Distilled Water ◽  
Water Control ◽  
Germinated Pollen ◽  
Autonomous Republic

Abstract. The zones of distribution of varieties and forms of quince on the territory of the Nakhchivan Autonomous Republic have been established, phenological observations have been carried out, their flowering and fruiting have been studied. On the territory of the Autonomous Republic, flowering of varieties and forms of quince begins in the second decade of April, depending on the distribution zone, with an average daily temperature of 12–13 °C and lasts 12–13 days, depending on weather conditions. Each flower has 10–12 stamens arranged in one row. The article also studied the viability of pollen in a number of quince varieties. Pollen viability was studied in the varieties Sary, Tursh, Ordubad, Gara and wild forms. Pollen fertility was determined by staining with acetocarmine. Pollen germinates in 2–5–10–15 and 20% glucose solution. Counting of germinated pollen grains was carried out under a microscope. The study showed that of all the experimental varieties, the pollen fertility of the Sary quince and Tursh quince varieties is high (up to 96.6–97.1%). The best medium for the germination of quince pollen is a 10–15% glucose solution. Pollen germination in this solution reaches 47.4–88.0%. In distilled water (control), the germination of quince pollen reached from 9.7% to 35.6% for varieties. Quince pollen remains viable for 31–43 days.

scholarly journals Impact of Manganese on Pollen Germination and Tube Growth in Lily

2021 ◽  
Vol 74 ◽  
Author(s):  
Thomas Sawidis ◽  
Gülriz Baycu ◽  
Elżbieta Weryszko-Chmielewska ◽  
Aneta Sulborska
Keyword(s):  
Pollen Tube ◽  
Pollen Germination ◽  
Surrounding Medium ◽  
Pollen Grains ◽  
Lilium Longiflorum ◽  
Tube Growth ◽  
Low Concentrations ◽  
Main Effect

Abstract In vitro culture of Lilium longiflorum pollen grains was carried out to determine the role of manganese in pollen germination and pollen tube growth. Pollen germination was adversely affected by the presence of manganese (>10 −8 M), whereas low concentrations (10 −12 –10 −10 M) stimulated the process. Manganese caused morphological anomalies during tube growth, characterized by irregular pollen tube thickening and swollen tips. The main effect was the anomalous cell wall formation at the tip, in which the presence of several organelles reduced the number of secretory vesicles. A loose network of fibrillar material and spherical aggregates, mostly in the tip region, was detected, and this material was progressively loosened into the surrounding medium. As a response to potential toxicity, the excess manganese was isolated in vacuoles, which formed an internal barrier against penetration of manganese to the tip area. Elevated manganese concentrations might affect plant reproduction, resulting in anomalies in gamete development. Consequently, the loss in genetic diversity and decreased fruit set ultimately lower yield.

scholarly journals Pollinator effectiveness of a specialist bee exploiting a generalist plant—tracking pollen transfer by Heriades truncorum with quantum dots

Apidologie ◽  
2019 ◽  
Vol 51 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Sabine Konzmann ◽  
Margareta Kluth ◽  
Deniz Karadana ◽  
Klaus Lunau
Keyword(s):  
Quantum Dots ◽  
Reproductive Success ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Pollen Transfer ◽  
Pollinator Effectiveness ◽  
Flower Constancy ◽  
Single Visit ◽  
Heriades Truncorum ◽  
Open Control

AbstractHeriades truncorum (Megachilidae) is a specialist bee that forages on Asteraceae and collects pollen by tapping its abdomen on pollen-presenting florets which places the grains directly in the ventral scopa. We tracked pollen transfer by female H. truncorum between conspecific inflorescences of Inula ensifolia and Pulicaria dysenterica by labelling pollen with quantum dots. On average, bees transferred 31.14 (I. ensifolia) and 9.96 (P. dysenterica) pollen grains from the last visited inflorescence, 39% and 45% of which were placed on receptive styles. Pollen germination ratio is significantly lower for inflorescences of P. dysenterica visited by one H. truncorum (0.13%) compared with open control inflorescences (0.51%), which suggests that the bees mainly transfer self-pollen of these self-incompatible plants. Thus, a single visit by H. truncorum does not grant the plant high reproductive success, but the bees’ abundance and flower constancy might reduce this disadvantage.

scholarly journals Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

2012 ◽  
Vol 39 (12) ◽  
pp. 1009 ◽  
Author(s):  
Viola Devasirvatham ◽  
Pooran M. Gaur ◽  
Nalini Mallikarjuna ◽  
Raju N. Tokachichu ◽  
Richard M. Trethowan ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Pollen Germination ◽  
Pollen Viability ◽  
Pollen Grains ◽  
High Temperature Stress ◽  
Pollen Production ◽  
Seed Number ◽  
Controlled Environments

High temperature during the reproductive stage in chickpea (Cicer arietinum L.) is a major cause of yield loss. The objective of this research was to determine whether that variation can be explained by differences in anther and pollen development under heat stress: the effect of high temperature during the pre- and post-anthesis periods on pollen viability, pollen germination in a medium, pollen germination on the stigma, pollen tube growth and pod set in a heat-tolerant (ICCV 92944) and a heat-sensitive (ICC 5912) genotype was studied. The plants were evaluated under heat stress and non-heat stress conditions in controlled environments. High temperature stress (29/16°C to 40/25°C) was gradually applied at flowering to study pollen viability and stigma receptivity including flower production, pod set and seed number. This was compared with a non-stress treatment (27/16°C). The high temperatures reduced pod set by reducing pollen viability and pollen production per flower. The ICCV 92944 pollen was viable at 35/20°C (41% fertile) and at 40/25°C (13% fertile), whereas ICC 5912 pollen was completely sterile at 35/20°C with no in vitro germination and no germination on the stigma. However, the stigma of ICC 5912 remained receptive at 35/20°C and non-stressed pollen (27/16°C) germinated on it during reciprocal crossing. These data indicate that pollen grains were more sensitive to high temperature than the stigma in chickpea. High temperature also reduced pollen production per flower, % pollen germination, pod set and seed number.

scholarly journals Can Selenium and Molybdenum Restrain Cadmium Toxicity to Pollen Grains in Brassica napus?

2018 ◽  
Vol 19 (8) ◽  
pp. 2163 ◽  
Author(s):  
Marwa Ismael ◽  
Ali Elyamine ◽  
Yuan Zhao ◽  
Mohamed Moussa ◽  
Muhammad Rana ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Brassica Napus ◽  
Pollen Germination ◽  
Foliar Application ◽  
Germination Rate ◽  
Pollen Grains ◽  
Cd Stress ◽  
Cd Uptake ◽  
Physiological Level ◽  
The Impact

Cadmium (Cd) is highly toxic, even at very low concentrations, to both animals and plants. Pollen is extremely sensitive to heavy metal pollutants; however, less attention has been paid to the protection of this vital part under heavy metal stress. A pot experiment was designed to investigate the effect of foliar application of Se (1 mg/L) and Mo (0.3 mg/L) either alone or in combination on their absorption, translocation, and their impact on Cd uptake and its further distribution in Brassica napus, as well as the impact of these fertilizers on the pollen grains morphology, viability, and germination rate in B. napus under Cd stress. Foliar application of either Se or Mo could counteract Cd toxicity and increase the plant biomass, while combined application of Se and Mo solutions on B. napus has no significant promotional effect on plant root and stem, but reduces the seeds’ weight by 10–11%. Se and Mo have decreased the accumulated Cd in seeds by 6.8% and 9.7%, respectively. Microscopic studies, SEM, and pollen viability tests demonstrated that pollen grains could be negatively affected by Cd, thus disturbing the plant fertility. Se and Mo foliar application could reduce the toxic symptoms in pollen grains when the one or the other was sprayed alone on plants. In an in vitro pollen germination test, 500 μM Cd stress could strongly inhibit the pollen germination rate to less than 2.5%, however, when Se (10 μM) or Mo (1.0 μM) was added to the germination medium, the rate increased, reaching 66.2% and 39.4%, respectively. At the molecular level, Se and Mo could greatly affect the expression levels of some genes related to Cd uptake by roots (IRT1), Cd transport (HMA2 and HMA4), Cd sequestration in plant vacuoles (HMA3), and the final Cd distribution in plant tissue at the physiological level (PCS1).

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