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Ryan Whitford - One of the best experts on this subject based on the ideXlab platform.

  • wheat tams1 is a glycosylphosphatidylinositol anchored lipid transfer protein necessary for Pollen Development
    BMC Plant Biology, 2018
    Co-Authors: Allan Kouidri, Ute Baumann, Takashi Okada, Mathieu Baes, Elise J Tucker, Ryan Whitford
    Abstract:

    In flowering plants, lipid biosynthesis and transport within anthers is essential for male reproductive success. TaMs1, a dominant wheat fertility gene located on chromosome 4BS, has been previously fine mapped and identified to encode a glycosylphosphatidylinositol (GPI)-anchored non-specific lipid transfer protein (nsLTP). Although this gene is critical for Pollen exine Development, details of its function remains poorly understood. In this study, we report that TaMs1 is only expressed from the B sub-genome, with highest transcript abundance detected in anthers containing microspores undergoing pre-meiosis through to meiosis. β-glucuronidase transcriptional fusions further revealed that TaMs1 is expressed throughout all anther cell-types. TaMs1 was identified to be expressed at an earlier stage of anther Development relative to genes reported to be necessary for sporoPollenin precursor biosynthesis. In anthers missing a functional TaMs1 (ms1c deletion mutant), these same genes were not observed to be mis-regulated, indicating an independent function for TaMs1 in Pollen Development. Exogenous hormone treatments on GUS reporter lines suggest that TaMs1 expression is increased by both indole-3-acetic acid (IAA) and abscisic acid (ABA). Translational fusion constructs showed that TaMs1 is targeted to the plasma membrane. In summary, TaMs1 is a wheat fertility gene, expressed early in anther Development and encodes a GPI-LTP targeted to the plasma membrane. The work presented provides a new insight into the process of wheat Pollen Development.

  • Wheat TaMs1 is a glycosylphosphatidylinositol-anchored lipid transfer protein necessary for Pollen Development
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Allan Kouidri, Ute Baumann, Takashi Okada, Mathieu Baes, Elise J Tucker, Ryan Whitford
    Abstract:

    Abstract Background In flowering plants, lipid biosynthesis and transport within anthers is essential for male reproductive success. TaMs1, a dominant wheat fertility gene located on chromosome 4BS, has been previously fine mapped and identified to encode a glycosylphosphatidylinositol (GPI)-anchored non-specific lipid transfer protein (nsLTP). Although this gene is critical for Pollen exine Development, details of its function remains poorly understood. Results In this study, we report that TaMs1 is only expressed from the B sub-genome, with highest transcript abundance detected in anthers containing microspores undergoing pre-meiosis through to meiosis. β-glucuronidase transcriptional fusions further revealed that TaMs1 is expressed throughout all anther cell-types. TaMs1 was identified to be expressed at an earlier stage of anther Development relative to genes reported to be necessary for sporoPollenin precursor biosynthesis. In anthers missing a functional TaMs1 (ms1c deletion mutant), these same genes were not observed to be mis-regulated, indicating an independent function for TaMs1 in Pollen Development. Exogenous hormone treatments on GUS reporter lines suggest that TaMs1 expression is increased by both indole-3-acetic acid (IAA) and abscisic acid (ABA). Translational fusion constructs showed that TaMs1 is targeted to the plasma membrane. Conclusions In summary, TaMs1 is a wheat fertility gene, expressed early in anther Development and encodes a GPI-LTP targeted to the plasma membrane. The work presented provides a new insight into the process of wheat Pollen Development

Luiz Orlando De Oliveira - One of the best experts on this subject based on the ideXlab platform.

  • reproductive studies in ipecac psychotria ipecacuanha brot stockes rubiaceae Pollen Development and morphology
    Brazilian Archives of Biology and Technology, 2008
    Co-Authors: Margarete Magalhaes Souza, Telma Nair Santana Pereira, Ernane Ronie Martins, Luiz Orlando De Oliveira
    Abstract:

    ABSTRACT The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The Pollen Development was observed from the sections of the anthers embedded in resin. Anther Development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothecium, middle layer and inner tapetum. The Pollen was bicellular and filled with starch at the microspore stage. Pollen morphology was studied using SEM, which showed Pollen polymorphism within and between the two floral morphs. Five types of Pollen with reticulate or perforate exine were identified. The characteristics showed that the sexual process was as important as the vegetative propagation for the reproduction of this species. Key words: Ipecac, heterostyly, anther anatomy, microsporogenesis, exine * Author for correspondence INTRODUCTION Poaia, ipeca or ipecacuanha are terms used in Brazil to designate the medicinal species, Psychotria ipecacuanha (Brot.) Stockes known as ipecac in English and raicilla in Central America countries (Torres, 1972). Its center of origin is in American continent. The native populations are restricted to three regions: Central America, Southwest of the Brazilian Amazon region (Mato Grosso and Rondonia States) and Atlantic forest, mainly in Minas Gerais, Espirito Santo, Rio de Janeiro and Bahia States (Assis, 1992). For the commercial cultivation, ipecac may be propagated by the sexual and asexual methods (Jha et al., 1988). The natural propagation occurs by the both vegetative multiplication and seeds that are transported by the birds, but the former is more important (Sick, 1993). This species presents heterostyly (Martins, 2000) like many others species belonging to its family, Rubiaceae (for

  • reproductive studies in ipecac psychotria ipecacuanha brot stockes rubiaceae Pollen Development and morphology
    Brazilian Archives of Biology and Technology, 2008
    Co-Authors: Margarete Magalhaes Souza, Telma Nair Santana Pereira, Ernane Ronie Martins, Luiz Orlando De Oliveira
    Abstract:

    The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The Pollen Development was observed from the sections of the anthers embedded in resin. Anther Development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothecium, middle layer and inner tapetum. The Pollen was bicellular and filled with starch at the microspore stage. Pollen morphology was studied using SEM, which showed Pollen polymorphism within and between the two floral morphs. Five types of Pollen with reticulate or perforate exine were identified. The characteristics showed that the sexual process was as important as the vegetative propagation for the reproduction of this species.

  • Reproductive studies in ipecac (Psychotria ipecacuanha (Brot.) stockes; Rubiaceae): Pollen Development and morphology
    Instituto de Tecnologia do Paraná (Tecpar), 2008
    Co-Authors: Margarete Magalhaes Souza, Telma Nair Santana Pereira, Ernane Ronie Martins, Luiz Orlando De Oliveira
    Abstract:

    The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The Pollen Development was observed from the sections of the anthers embedded in resin. Anther Development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothecium, middle layer and inner tapetum. The Pollen was bicellular and filled with starch at the microspore stage. Pollen morphology was studied using SEM, which showed Pollen polymorphism within and between the two floral morphs. Five types of Pollen with reticulate or perforate exine were identified. The characteristics showed that the sexual process was as important as the vegetative propagation for the reproduction of this species.Foram realizados estudos reprodutivos em acessos brasileiros de poaia, Psychotria ipecacuanha. Poaia apresenta heterostilia, com flores brevistilas e longistilas. O desenvolvimento do pólen foi estudado em cortes de anteras embebidas em resina. O desenvolvimento da antera seguiu o padrão normal para as dicotiledôneas, a qual apresentou quatro camadas: epiderme, endotécio, camada média, e tapete, a mais interna. O pólen apresentou-se bicelular e preenchido com amido no estágio de micrósporo. A morfologia do pólen foi estudada utilizando-se MEV. Foi observado polimorfismo polínico dentro e entre as duas formas florais. Foram identificados cinco tipos de grãos de pólen, com exina reticulada ou perfurada. Em seu hábitat natural, sabe-se que essa espécie apresenta propagação por multiplicação vegetativa, mas as características estudadas demonstraram que o mecanismo sexuado é tão importante para a reprodução dessa espécie quanto à propagação vegetativa

Robert E Cleland - One of the best experts on this subject based on the ideXlab platform.

  • two callose synthases gsl1 and gsl5 play an essential and redundant role in plant and Pollen Development and in fertility
    Plant Molecular Biology, 2005
    Co-Authors: Linda C Enns, Masahiro M Kanaoka, Kiyotaka Okada, Keiko U Torii, Luca Comai, Robert E Cleland
    Abstract:

    Callose, a β-1,3-glucan that is widespread in plants, is synthesized by callose synthase. Arabidopsis thaliana contains a family of 12 putative callose synthase genes (GSL1–12). The role of callose and of the individual genes in plant Development is still largely uncertain. We have now used TILLING and T-DNA insertion mutants (gsl1-1, gsl5-2 and gsl5-3) to study the role of two closely related and linked genes, GSL1 and GSL5, in sporophytic Development and in reproduction. Both genes are expressed in all parts of the plant. Sporophytic Development was nearly normal in gsl1-1 homozygotes and only moderately defective in homozygotes for either of the two gsl5 alleles. On the other hand, plants that were gsl1-1/+ gsl5/gsl5 were severely defective, with smaller leaves, shorter roots and bolts and smaller flowers. Plants were fertile when the sporophytes had either two wild-type GSL1 alleles, or one GSL5 allele in a gsl1-1 background, but gsl1-1/+ gsl5/gsl5 plants produced an extremely reduced number of viable seeds. A chromosome with mutations in both GSL1 and GSL5 rendered Pollen infertile, although such a chromosome could be transmitted via the egg. As a result, it was not possible to obtain plants that were homozygous for mutations in both the GSL genes. Pollen grain Development was severely affected in double mutant plants. Many Pollen grains were collapsed and inviable in the gsl1-1/gsl1-1 gsl5/+ and gsl1-1/+ gsl5/gsl5 plants. In addition, gsl1-1/+ gsl5/gsl5 plants produced abnormally large Pollen with unusual pore structures, and had problems with tetrad dissociation. In this particular genotype, while the callose wall formed around the Pollen mother cells, no callose wall separated the resulting tetrads. We conclude that GSL1 and GSL5 play important, but at least partially redundant roles in both sporophytic Development and in the Development of Pollen. They are responsible for the formation of the callose wall that separates the microspores of the tetrad, and also play a gametophytic role later in Pollen grain maturation. Other GSL genes may control callose formation at different steps during Pollen Development.

  • two callose synthases gsl1 and gsl5 play an essential and redundant role in plant and Pollen Development and in fertility
    Plant Molecular Biology, 2005
    Co-Authors: Linda C Enns, Masahiro M Kanaoka, Kiyotaka Okada, Keiko U Torii, Luca Comai, Robert E Cleland
    Abstract:

    Callose, a beta-1,3-glucan that is widespread in plants, is synthesized by callose synthase. Arabidopsis thaliana contains a family of 12 putative callose synthase genes (GSL1-12). The role of callose and of the individual genes in plant Development is still largely uncertain. We have now used TILLING and T-DNA insertion mutants (gsl1-1, gsl5-2 and gsl5-3) to study the role of two closely related and linked genes, GSL1 and GSL5, in sporophytic Development and in reproduction. Both genes are expressed in all parts of the plant. Sporophytic Development was nearly normal in gsl1-1 homozygotes and only moderately defective in homozygotes for either of the two gsl5 alleles. On the other hand, plants that were gsl1-1/+ gsl5/gsl5 were severely defective, with smaller leaves, shorter roots and bolts and smaller flowers. Plants were fertile when the sporophytes had either two wild-type GSL1 alleles, or one GSL5 allele in a gsl1-1 background, but gsl1-1/+ gsl5/gsl5 plants produced an extremely reduced number of viable seeds. A chromosome with mutations in both GSL1 and GSL5 rendered Pollen infertile, although such a chromosome could be transmitted via the egg. As a result, it was not possible to obtain plants that were homozygous for mutations in both the GSL genes. Pollen grain Development was severely affected in double mutant plants. Many Pollen grains were collapsed and inviable in the gsl1-1/gsl1-1 gsl5/+ and gsl1-1/+ gsl5/gsl5 plants. In addition, gsl1-1/+ gsl5/gsl5 plants produced abnormally large Pollen with unusual pore structures, and had problems with tetrad dissociation. In this particular genotype, while the callose wall formed around the Pollen mother cells, no callose wall separated the resulting tetrads. We conclude that GSL1 and GSL5 play important, but at least partially redundant roles in both sporophytic Development and in the Development of Pollen. They are responsible for the formation of the callose wall that separates the microspores of the tetrad, and also play a gametophytic role later in Pollen grain maturation. Other GSL genes may control callose formation at different steps during Pollen Development.

Roger W Parish - One of the best experts on this subject based on the ideXlab platform.

  • myb80 a regulator of tapetal and Pollen Development is functionally conserved in crops
    Plant Molecular Biology, 2012
    Co-Authors: Huy Anh Phan, Roger W Parish
    Abstract:

    The Arabidopsis AtMYB80 transcription factor (formerly AtMYB103) regulate genes essential for tapetal and Pollen Development. One of these genes, coding for an aspartic protease (UNDEAD), may control the timing of tapetal programmed cell death (PCD). In crop plants such as rice and wheat, abiotic stresses lead to abnormal tapetal Development resulting in delayed PCD. Manipulation of AtMYB80 function has been used to develop a reversible male sterility system applicable to hybrid crop production. MYB80 homologs were cloned from wheat, rice, canola and cotton. The promoters of the homologs drove temporal and spatial expression patterns of the GUS reporter gene in the tapetum and microspores of Arabidopsis anthers identical to the AtMYB80 promoter. A short region is conserved in all five MYB80 promoters. The MYB80 homolog genes, driven by the AtMYB80 or their respective promoters, rescued the atmyb80 mutant, completely restoring male fertility. The canola MYB80 was fused to the EAR (ERF-associated amphiphilic repression) repressor and canola plants transgenic for the construct exhibited premature tapetal degradation and subsequent Pollen abortion. The five MYB80 homologs all shared a 44 amino acid sequence immediately adjacent to the R2R3 domain which appears to be necessary for MYB80 function.

  • the myb80 transcription factor is required for Pollen Development and the regulation of tapetal programmed cell death in arabidopsis thaliana
    The Plant Cell, 2011
    Co-Authors: Huy Anh Phan, Sylvana Iacuone, Roger W Parish
    Abstract:

    Arabidopsis thaliana MYB80 (formerly MYB103) is expressed in the tapetum and microspores between anther Developmental stages 6 and 10. MYB80 encodes a MYB transcription factor that is essential for tapetal and Pollen Development. Using microarray analysis of anther mRNA, we identified 404 genes differentially expressed in the myb80 mutant. Employing the glucocorticoid receptor system, the expression of 79 genes was changed when MYB80 function was restored in the myb80 mutant following induction by dexamethasone. Thirty-two genes were analyzed using chromatin immunoprecipitation, and three were identified as direct targets of MYB80. The genes encode a glyoxal oxidase (GLOX1), a pectin methylesterase (VANGUARD1), and an A1 aspartic protease (UNDEAD). All three genes are expressed in the tapetum and microspores. Electrophoretic mobility shift assays confirmed that MYB80 binds to all three target promoters, with the preferential binding site containing the CCAACC motif. TUNEL assays showed that when UNDEAD expression was silenced using small interfering RNA, premature tapetal and Pollen programmed cell death occurred, resembling the myb80 mutant phenotype. UNDEAD possesses a mitochondrial targeting signal and may hydrolyze an apoptosis-inducing protein(s) in mitochondria. The timing of tapetal programmed cell death is critical for Pollen Development, and the MYB80/UNDEAD system may regulate that timing.

  • atmyb32 is required for normal Pollen Development in arabidopsis thaliana
    Plant Journal, 2004
    Co-Authors: Jeremy Preston, Janet Wheeler, Joshua L Heazlewood, Roger W Parish
    Abstract:

    AtMYB32 gene is a member of the R2R3 MYB gene family coding for transcription factors in Arabidopsis thaliana. Its expression pattern was analysed using Northern blotting, in situ hybridization and promoter-GUS fusions. AtMYB32 is expressed in many tissues, but most strongly in the anther tapetum, stigma papillae and lateral root primordia. AtMYB32-GUS was induced in leaves and stems following wounding, and in root primordia by auxin. T-DNA insertion populations were screened and two insertion mutants were identified, both of which were partially male sterile, more than 50% of the Pollen grains being distorted in shape and lacking cytoplasm. AtMYB4 is closely related to AtMYB32 and represses the CINNAMATE 4-HYDROXYLASE gene. Distorted Pollen grains were produced in both AtMYB4 insertion mutant and overexpression lines. In an AtMYB32 insertion mutant, the transcript levels of the DIHYDROFLAVONOL 4-REDUCTASE and ANTHOCYANIDIN SYNTHASE genes decreased while the level of the CAFFEIC ACID 0-METHYLTRANSFERASE transcript increased. Change in the levels of AtMYB32 and AtMYB4 expression may influence Pollen Development by changing the flux along the phenylpropanoid pathways, affecting the composition of the Pollen wall.

Yuzhi Zhang - One of the best experts on this subject based on the ideXlab platform.

  • comparative transcriptome analysis and chip sequencing reveals stage specific gene expression and regulation profiles associated with Pollen wall formation in brassica rapa
    BMC Genomics, 2019
    Co-Authors: Heng Dong, Dong Zhou, Yanhong Liu, Xiuping Shen, Yuzhi Zhang
    Abstract:

    Genic male sterility (GMS) line is an important approach to utilize heterosis in Brassica rapa, one of the most widely cultivated vegetable crops in Northeast Asia. However, the molecular genetic mechanisms of GMS remain to be largely unknown. Detailed phenotypic observation of ‘Bcajh97-01A/B’, a B. rapa genic male sterile AB line in this study revealed that the aberrant meiotic cytokinesis and premature tapetal programmed cell death occurring in the sterile line ultimately resulted in microspore degeneration and Pollen wall defect. Further gene expression profile of the sterile and fertile floral buds of ‘Bcajh97-01A/B’ at five typical Developmental stages during Pollen Development supported the result of phenotypic observation and identified stage-specific genes associated with the main events associated with Pollen wall Development, including tapetum Development or functioning, callose metabolism, Pollen exine formation and cell wall modification. Additionally, by using ChIP-sequencing, the genomic and gene-level distribution of trimethylated histone H3 lysine 4 (H3K4) and H3K27 were mapped on the fertile floral buds, and a great deal of Pollen Development-associated genes that were covalently modified by H3K4me3 and H3K27me3 were identified. Our study provids a deeper understanding into the gene expression and regulation network during Pollen Development and Pollen wall formation in B. rapa, and enabled the identification of a set of candidate genes for further functional annotation.

  • Comparative transcriptome analysis and ChIP-sequencing reveals stage-specific gene expression and regulation profiles associated with Pollen wall formation in Brassica rapa
    BMC, 2019
    Co-Authors: Xiuping Shen, Heng Dong, Dong Zhou, Yanhong Liu, Sue Lin, Jiashu Cao, Yuzhi Zhang, Li Huang
    Abstract:

    Abstract Background Genic male sterility (GMS) line is an important approach to utilize heterosis in Brassica rapa, one of the most widely cultivated vegetable crops in Northeast Asia. However, the molecular genetic mechanisms of GMS remain to be largely unknown. Results Detailed phenotypic observation of ‘Bcajh97-01A/B’, a B. rapa genic male sterile AB line in this study revealed that the aberrant meiotic cytokinesis and premature tapetal programmed cell death occurring in the sterile line ultimately resulted in microspore degeneration and Pollen wall defect. Further gene expression profile of the sterile and fertile floral buds of ‘Bcajh97-01A/B’ at five typical Developmental stages during Pollen Development supported the result of phenotypic observation and identified stage-specific genes associated with the main events associated with Pollen wall Development, including tapetum Development or functioning, callose metabolism, Pollen exine formation and cell wall modification. Additionally, by using ChIP-sequencing, the genomic and gene-level distribution of trimethylated histone H3 lysine 4 (H3K4) and H3K27 were mapped on the fertile floral buds, and a great deal of Pollen Development-associated genes that were covalently modified by H3K4me3 and H3K27me3 were identified. Conclusions Our study provids a deeper understanding into the gene expression and regulation network during Pollen Development and Pollen wall formation in B. rapa, and enabled the identification of a set of candidate genes for further functional annotation