The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
David Honys - One of the best experts on this subject based on the ideXlab platform.
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Characterization of pollen-expressed bZIP protein interactions and the role of ATbZIP18 in the Male Gametophyte
Plant Reproduction, 2017Co-Authors: Antónia Gibalová, Said Hafidh, Lenka Steinbachová, Veronika Bláhová, Zuzana Gadiou, Christos Michailidis, Karel Műller, Roman Pleskot, Nikoleta Dupľáková, David HonysAbstract:Key message bZIP TF network in pollen. Abstract Transcriptional control of gene expression represents an important mechanism guiding organisms through developmental processes and providing plasticity towards environmental stimuli. Because of their sessile nature, plants require effective gene regulation for rapid response to variation in environmental and developmental conditions. Transcription factors (TFs) provide such control ensuring correct gene expression in spatial and temporal manner. Our work reports the interaction network of six bZIP TFs expressed in Arabidopsis thaliana pollen and highlights the potential functional role for AtbZIP18 in pollen. AtbZIP18 was shown to interact with three other pollen-expressed bZIP TFs—AtbZIP34, AtbZIP52, and AtbZIP61 in yeast two-hybrid assays. AtbZIP18 transcripts are highly expressed in pollen, and at the subcellular level, an AtbZIP18-GFP fusion protein was located in the nucleus and cytoplasm/ER. To address the role of AtbZIP18 in the Male Gametophyte, we performed phenotypic analysis of a T-DNA knockout allele, which showed slightly reduced transmission through the Male Gametophyte. Some of the phenotype defects in atbzip18 pollen, although observed at low penetrance, were similar to those seen at higher frequency in the T-DNA knockout of the interacting partner, AtbZIP34. To gain deeper insight into the regulatory role of AtbZIP18, we analysed atbzip18 /– pollen microarray data. Our results point towards a potential repressive role for AtbZIP18 and its functional redundancy with AtbZIP34 in pollen.
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Rapid separation of Arabidopsis Male Gametophyte developmental stages using a Percoll gradient
Nature Protocols, 2016Co-Authors: Nikoleta Dupl'áková, Petre I Dobrev, David Reňák, David HonysAbstract:Research investigating the dynamics of Male Gametophyte (MG) development has proven to be challenging for the plant science community. Here we describe our protocol for separating Arabidopsis MG developmental stages, which is based on the centrifugation of pollen through a discontinuous Percoll concentration gradient. This Percoll gradient can be formed using a pipette, and it does not require a gradient maker. The purity of the isolated developing spores is as high as 70%, and in most separations it is well above 80%. Using this protocol, we can separate four different stages of pollen development—uninucleate microspore (UNM), bicellular pollen (BCP), tricellular immature pollen (TCP) and mature pollen grain (MPG). The duration of the separation procedure, excluding the cutting of flower inflorescences, is 6 h. This is reduced to 4 h when using a vacuum cleaning method to remove the MPGs before the Percoll density separation. Dupl'áková et al . describe a protocol to separate different developmental stages of the Male Gametophyte (MG) in A. thaliana . To achieve this, MG is subjected to rate-zonal centrifugation through a discontinuous Percoll density gradient.
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rapid separation of arabidopsis Male Gametophyte developmental stages using a percoll gradient
Nature Protocols, 2016Co-Authors: Nikoleta Duplakova, Petre I Dobrev, David Reňák, David HonysAbstract:Research investigating the dynamics of Male Gametophyte (MG) development has proven to be challenging for the plant science community. Here we describe our protocol for separating Arabidopsis MG developmental stages, which is based on the centrifugation of pollen through a discontinuous Percoll concentration gradient. This Percoll gradient can be formed using a pipette, and it does not require a gradient maker. The purity of the isolated developing spores is as high as 70%, and in most separations it is well above 80%. Using this protocol, we can separate four different stages of pollen development-uninucleate microspore (UNM), bicellular pollen (BCP), tricellular immature pollen (TCP) and mature pollen grain (MPG). The duration of the separation procedure, excluding the cutting of flower inflorescences, is 6 h. This is reduced to 4 h when using a vacuum cleaning method to remove the MPGs before the Percoll density separation.
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Male Gametophyte development and function in angiosperms: a general concept
Plant Reproduction, 2016Co-Authors: Said Hafidh, Jan Fíla, David HonysAbstract:Key message Overview of pollen development. Abstract Male Gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis—developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between Male and feMale Gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca^2+ and H^+ ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.
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Male Gametophyte development and function in angiosperms a general concept
Sexual Plant Reproduction, 2016Co-Authors: Said Hafidh, Jan Fíla, David HonysAbstract:Overview of pollen development. Male Gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis—developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between Male and feMale Gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca2+ and H+ ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.
David Twell - One of the best experts on this subject based on the ideXlab platform.
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a ticket for the live show microtubules in Male Gametophyte development
Plant Signaling & Behavior, 2010Co-Authors: Trudie Allen, David TwellAbstract:Microtubule-reporter plants expressing green fluorescent protein-α-TUBULIN fusion protein (GFP-TUA6) in Male gametophytic cells of tobacco and Arabidopsis provide new tools for studying the native organization of microtubule (MT) arrays during reproductive development. These plants reveal unique features of gametophytic MT arrays including a basket-like cortical MT array in polarized microspores at interphase, an asymmetric spindle and curved phragmoplast MTs at microspore division and an assembly of bundled cortical MTs during germ cell morphogenesis. The application of these MT-reporter plants has been demonstrated by RNAi-mediated knockdown of the microtubule-associated protein TMBP200, the tobacco orthologue of the conserved MAP215/Dis1 family protein. The double transgenic lines display defects in nuclear positioning, division asymmetry and cytokinesis that are associated with striking defects in spindle and phragmoplast position and organization. This study reveals native and altered MT arrays in unprecedented detail and clarifies the essential functions of MAP215/Dis1 protein function in successive steps in Male germline establishment. Such gametophytic MT-reporter lines should accelerate studies of the dynamic regulation of MT arrays by microtubule associated proteins and other effectors during Male Gametophyte development.
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Life after meiosis: patterning the angiosperm Male Gametophyte
Biochemical Society Transactions, 2010Co-Authors: Michael A. Borg, David TwellAbstract:Pollen grains represent the highly reduced haploid Male Gametophyte generation in angiosperms. They play an essential role in plant fertility by generating and delivering twin sperm cells to the embryo sac to undergo double fertilization. The functional specialization of the Male Gametophyte and double fertilization are considered to be key innovations in the evolutionary success of angiosperms. The haploid nature of the Male Gametophyte and its highly tractable ontogeny makes it an attractive system to study many fundamental biological processes, such as cell fate determination, cell-cycle progression and gene regulation. The present mini-review encompasses key advances in our understanding of the molecular mechanisms controlling Male Gametophyte patterning in angiosperms. A brief overview of Male Gametophyte development is presented, followed by a discussion of the genes required at landmark events of Male gametogenesis. The value of the Male Gametophyte as an experimental system to study the interplay between cell fate determination and cell-cycle progression is also discussed and exemplified with an emerging model outlining the regulatory networks that distinguish the fate of the Male germline from its sister vegetative cell. We conclude with a perspective of the impact emerging data will have on future research strategies and how they will develop further our understanding of Male gametogenesis and plant development.
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Male Gametophyte Development
Plant Developmental Biology - Biotechnological Perspectives, 2009Co-Authors: David TwellAbstract:The highly reduced haploid Gametophyte generation in seed plants occupies a short but vital phase in the plant life cycle. The Male Gametophytes of flowering plants are highly specialized two- or three-celled pollen grains that nurture and deliver twin Male gametes or sperm cells to the feMale gametes at fertilisation. This functional specialization is highly developed and a key innovation in the evolutionary success of flowering plants. Recent progress in understanding the molecular cellular processes during pollen development is reviewed from the formation of unicellular microspores to the point of pollen shed. Substantial advances have been achieved principally through two complementary approaches: the analysis of gametophytic mutants, and in the application of genomic technologies to uncover the complexity and regulation of the haploid transcriptome during Male Gametophyte development.
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small rna pathways are present and functional in the angiosperm Male Gametophyte
Molecular Plant, 2009Co-Authors: Robert Grantdownton, David Twell, Said Hafidh, H G DickinsonAbstract:Small non-coding RNAs are essential for development of the sporophyte, the somatic diploid phase of flowering plants. They are integral to key cellular processes such as defense, generation of chromatin structure, and regulation of native gene expression. Surprisingly, very little is known of their presence and function in the Male haploid phase of plant development (Male Gametophyte/pollen grain), where dramatic cell fate changes leading to gametogenesis occur over just two mitotic divisions. We show that critical components of small RNA pathways are expressed throughout pollen development, but in a pattern that differs from the sporophyte. We also demonstrate that mature pollen accumulates a range of mature microRNAs, the class of small RNA most frequently involved in post-transcriptional regulation of endogenous gene expression. Significantly, these miRNAs cleave their target transcripts in developing pollen—a process that seemingly contributes to the purging of key regulatory transcripts from the mature pollen grain. Small RNAs are thus likely to make a hitherto unappreciated contribution to Male Gametophyte gene expression patterns, pollen development, and gametogenesis.
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Male Gametophyte development a molecular perspective
Journal of Experimental Botany, 2009Co-Authors: M A Borg, Lynette Brownfield, David TwellAbstract:Pollen grains represent the highly reduced haploid Male Gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell. This double fertilization event along with the functional specialization of the Male Gametophyte, are considered to be key innovations in the evolutionary success of flowering plants. This review encompasses important recent advances in our understanding of the molecular mechanisms controlling Male Gametophyte development. A brief overview of pollen development is presented, followed by a discussion of genome-wide transcriptomic studies of haploid gene expression. The progress achieved through genetic analysis of landmark events of Male gametogenesis is discussed, with a focus on sperm cell production, and an emerging model of the regulatory network governing Male germline development is presented. The review concludes with a perspective of the impact these data will have on future research strategies to further develop our understanding of the gametophytic control of pollen development.
Xiaoming Pang - One of the best experts on this subject based on the ideXlab platform.
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megasporogenesis microsporogenesis and feMale and Male Gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Xiang Li, Feiyi Huang, Xiaoming Pang, Yingyue LiAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of Male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
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megasporogenesis microsporogenesis and feMale and Male Gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Ye Guo, Feiyi Huang, Xiaoming PangAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of Male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
Petre I Dobrev - One of the best experts on this subject based on the ideXlab platform.
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Rapid separation of Arabidopsis Male Gametophyte developmental stages using a Percoll gradient
Nature Protocols, 2016Co-Authors: Nikoleta Dupl'áková, Petre I Dobrev, David Reňák, David HonysAbstract:Research investigating the dynamics of Male Gametophyte (MG) development has proven to be challenging for the plant science community. Here we describe our protocol for separating Arabidopsis MG developmental stages, which is based on the centrifugation of pollen through a discontinuous Percoll concentration gradient. This Percoll gradient can be formed using a pipette, and it does not require a gradient maker. The purity of the isolated developing spores is as high as 70%, and in most separations it is well above 80%. Using this protocol, we can separate four different stages of pollen development—uninucleate microspore (UNM), bicellular pollen (BCP), tricellular immature pollen (TCP) and mature pollen grain (MPG). The duration of the separation procedure, excluding the cutting of flower inflorescences, is 6 h. This is reduced to 4 h when using a vacuum cleaning method to remove the MPGs before the Percoll density separation. Dupl'áková et al . describe a protocol to separate different developmental stages of the Male Gametophyte (MG) in A. thaliana . To achieve this, MG is subjected to rate-zonal centrifugation through a discontinuous Percoll density gradient.
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rapid separation of arabidopsis Male Gametophyte developmental stages using a percoll gradient
Nature Protocols, 2016Co-Authors: Nikoleta Duplakova, Petre I Dobrev, David Reňák, David HonysAbstract:Research investigating the dynamics of Male Gametophyte (MG) development has proven to be challenging for the plant science community. Here we describe our protocol for separating Arabidopsis MG developmental stages, which is based on the centrifugation of pollen through a discontinuous Percoll concentration gradient. This Percoll gradient can be formed using a pipette, and it does not require a gradient maker. The purity of the isolated developing spores is as high as 70%, and in most separations it is well above 80%. Using this protocol, we can separate four different stages of pollen development-uninucleate microspore (UNM), bicellular pollen (BCP), tricellular immature pollen (TCP) and mature pollen grain (MPG). The duration of the separation procedure, excluding the cutting of flower inflorescences, is 6 h. This is reduced to 4 h when using a vacuum cleaning method to remove the MPGs before the Percoll density separation.
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cytoskeleton associated large rnp complexes in tobacco Male Gametophyte epps are associated with ribosomes and are involved in protein synthesis processing and localization
Journal of Proteome Research, 2009Co-Authors: D Honys, D Rĕnak, J Fecikova, Petr Jedelský, Jana Nebesarova, Petre I DobrevAbstract:The progamic phase of Male Gametophyte development involves activation of synthetic and catabolic processes required for the rapid growth of the pollen tube. It is well-established that both transcription and translation play an important role in global and specific gene expression patterns during pollen maturation. On the contrary, germination of many pollen species has been shown to be largely independent of transcription but vitally dependent on translation of stored mRNAs. Here, we report the first structural and proteomic data about large ribonucleoprotein particles (EPPs) in tobacco Male Gametophyte. These complexes are formed in immature pollen where they contain translationally silent mRNAs. Although massively activated at the early progamic phase, they also serve as a long-term storage of mRNA transported along with the translational machinery to the tip region. Moreover, EPPs were shown to contain ribosomal subunits, rRNAs and a set of mRNAs. Presented results extend our view of EPP complexes from mere RNA storage and transport compartment in particular stages of pollen development to the complex and well-organized machinery devoted to mRNA storage, transport and subsequent controlled activation resulting in protein synthesis, processing and precise localization. Such an organization is extremely useful in fast tip-growing pollen tube. There, massive and orchestrated protein synthesis, processing, and transport must take place in accurately localized regions. Moreover, presented complex role of EPPs in tobacco cytoplasmic mRNA and protein metabolism makes them likely to be active in another plant species too. Expression of vast majority of the closest orthologues of EPP proteins also in Arabidopsis Male Gametophyte further extends this concept from tobacco to Arabidopsis, the model species with advanced tricellular pollen.
Yingyue Li - One of the best experts on this subject based on the ideXlab platform.
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megasporogenesis microsporogenesis and feMale and Male Gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Xiang Li, Feiyi Huang, Xiaoming Pang, Yingyue LiAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of megasporogenesis, microsporogenesis, and feMale and Male Gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of Male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.