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Virginia Walbot - One of the best experts on this subject based on the ideXlab platform.
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pre meiotic anther development
Current Topics in Developmental Biology, 2019Co-Authors: Karina Van Der Linde, Virginia WalbotAbstract:Abstract Most genetic and molecular analyses of anther development utilize Arabidopsis thaliana, Oryza sativa (rice), and Zea mays (maize). Especially in maize, early stages of anther development are easy to study because: (1) Maize has unisex flowers. (2) Compared to rice or A. thaliana, maize Anthers are relatively large, making dissection for molecular and biochemical analyses easy. (3) Anther developmental stage is strongly correlated with maize anther length. Besides these technical advantages, understanding anther and pollen development in maize is of significant agricultural importance. Today maize is a worldwide cereal crop: approximately 25% of all consumed food contains maize. Yield stability or even increases depend on maintenance of hybrid vigor, and production of hybrid seed requires manual detasseling or genetic control of pollen development. Knowledge of pollen development can also be used to manage transgene containment. In the first section of this chapter, we will describe the current model for sequential cell fate specification in maize anther lobes, with reference to rice and A. thaliana to point out similarities and differences. In the second section of this chapter, we will review what is known about the individual cell types in anther lobes. The diversity of anther organization is addressed to a limited extent by cytological studies of Anthers, often directed to clarify taxonomic relationships. In the third section, we will comment on how new lines of investigation could clarify questions remaining in our current appreciation of anther development.
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chloroplasts in anther endothecium of zea mays poaceae
American Journal of Botany, 2015Co-Authors: Katherine M Murphy, Rachel L Egger, Virginia WalbotAbstract:PREMISE OF THE STUDY: Although Anthers of Zea mays, Oryza sativa, and Arabidopsis thaliana have been studied intensively using genetic and biochemical analyses in the past 20 years, few updates to anther anatomical and ultrastructural descriptions have been reported. For example, no transmission electron microscopy (TEM) images of the premeiotic maize anther have been published. Here we report the presence of chloroplasts in maize Anthers. METHODS: TEM imaging, electron acceptor photosynthesis assay, in planta photon detection, microarray analysis, and light and fluorescence microscopy were used to investigate the presence of chloroplasts in the maize anther. KEY RESULTS: Most cells of the maize subepidermal endothecium have starch-containing chloroplasts that do not conduct measurable photosynthesis in vitro. CONCLUSIONS: The maize anther contains chloroplasts in most subepidermal, endothecial cells. Although maize Anthers receive sufficient light to photosynthesize in vivo and the maize anther transcribes >96% of photosynthesis-associated genes found in the maize leaf, no photosynthetic light reaction activity was detected in vitro. The endothecial cell layer should no longer be defined as a complete circle viewed transversely in anther lobes, because chloroplasts are observed only in cells directly beneath the epidermis and not those adjacent to the connective tissue. We propose that chloroplasts be a defining characteristic of differentiated endothecial cells and that nonsubepidermal endothecial cells that lack chloroplasts be defined as a separate cell type, the interendothecium.
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ustilago maydis reprograms cell proliferation in maize Anthers
Plant Journal, 2013Co-Authors: Li Gao, Timothy Kelliher, Linda Nguyen, Virginia WalbotAbstract:Summary The basidiomycete Ustilago maydis is a ubiquitous pathogen of maize (Zea mays), one of the world's most important cereal crops. Infection by this smut fungus triggers tumor formation in aerial plant parts within which the fungus sporulates. Using confocal microscopy to track U. maydis infection on corn Anthers for 7 days post-injection, we found that U. maydis is located on the epidermis during the first 2 days, and has reached all anther lobe cell types by 3 days post-injection. Fungal infection alters cell-fate specification events, cell division patterns, host cell expansion and host cell senescence, depending on the developmental stage and cell type. Fungal effects on tassel and plant growth were also quantified. Transcriptome profiling using a dual organism microarray identified thousands of anther genes affected by fungal infection at 3 days post-injection during the cell-fate specification and rapid cell proliferation phases of anther development. In total, 4147 (17%) of anther-expressed genes were altered by infection, 2018 fungal genes were expressed in Anthers, and 206 fungal secretome genes may be anther-specific. The results confirm that U. maydis deploys distinct genes to cause disease in specific maize organs, and suggest mechanisms by which the host plant is manipulated to generate a tumor.
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male reproductive development gene expression profiling of maize anther and pollen ontogeny
Genome Biology, 2008Co-Authors: David S Skibbe, John Fernandes, Virginia WalbotAbstract:During flowering, central anther cells switch from mitosis to meiosis, ultimately forming pollen containing haploid sperm. Four rings of surrounding somatic cells differentiate to support first meiosis and later pollen dispersal. Synchronous development of many Anthers per tassel and within each anther facilitates dissection of carefully staged maize Anthers for transcriptome profiling. Global gene expression profiles of 7 stages representing 29 days of anther development are analyzed using a 44 K oligonucleotide array querying approximately 80% of maize protein-coding genes. Mature haploid pollen containing just two cell types expresses 10,000 transcripts. Anthers contain 5 major cell types and express >24,000 transcript types: each anther stage expresses approximately 10,000 constitutive and approximately 10,000 or more transcripts restricted to one or a few stages. The lowest complexity is present during meiosis. Large suites of stage-specific and co-expressed genes are identified through Gene Ontology and clustering analyses as functional classes for pre-meiotic, meiotic, and post-meiotic anther development. MADS box and zinc finger transcription factors with constitutive and stage-limited expression are identified. We propose that the extensive gene expression of anther cells and pollen represents the key test of maize genome fitness, permitting strong selection against deleterious alleles in diploid Anthers and haploid pollen. Because flowering plants show a substantial bias for male-sterile compared to female-sterile mutations, we propose that this fitness test is general. Because both somatic and germinal cells are transcriptionally quiescent during meiosis, we hypothesize that successful completion of meiosis is required to trigger maturation of anther somatic cells.
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transcriptome profiling of maize Anthers using genetic ablation to analyze pre meiotic and tapetal cell types
Plant Journal, 2007Co-Authors: David S Duncan, John Fernandes, Darren J Morrow, Virginia WalbotAbstract:Oligonucleotide arrays were used to profile gene expression in dissected maize Anthers at four stages: after-anther initiation, at the rapid mitotic proliferation stage, pre-meiosis, and meiotic prophase I. Nearly 9200 sense and antisense transcripts were detected, with the most diverse transcriptome present at the pre-meiotic stage. Three male-sterile mutants lacking a range of normal cell types resulting from a temporal progression of anther failure were compared with fertile siblings at equivalent stages by transcription profiles. The msca1 mutant has the earliest visible phenotype, develops none of the normal anther cell types and exhibits the largest deviation from fertile siblings. The mac1 mutant has an excess of archesporial derivative cells and lacks a tapetum and middle layer, resulting in moderate transcriptional deviations. The ms23 mutant lacks a differentiated tapetum and shows the fewest differences from fertile Anthers. By combining the data sets from the comparisons between individual sterile and fertile Anthers, candidate genes predicted to play important roles during maize anther development were assigned to stages and to likely cell types. Comparative analyses with a data set of anther-specific genes from rice highlight remarkable quantitative similarities in gene expression between these two grasses.
David Weiss - One of the best experts on this subject based on the ideXlab platform.
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gibberellin regulates post microsporogenesis processes in petunia Anthers
Physiologia Plantarum, 2002Co-Authors: Anat Izhaki, Amihud Borochov, Eliezer Zamski, David WeissAbstract:Previous studies have suggested that gibberellins (GAs) are produced in petunia Anthers and transported to the corolla to induce growth and pigmentation. In this work, we studied the role of GA in the regulation of anther development. When petunia plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these Anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated Anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. A similar phenotype was obtained when the Arabidopsis GA-signal repressor, SPY, was over-expressed in transgenic petunia plants, i.e. anther development was arrested following microsporogenesis. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to study GA responses. GA3 treatment of young Anthers promoted, and paclobutrazol inhibited, GIP expression, suggesting that the hormone controls the natural activation of the gene in the Anthers. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development.
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Gibberellin regulates post‐microsporogenesis processes in petunia Anthers
Physiologia plantarum, 2002Co-Authors: Anat Izhaki, Amihud Borochov, Eliezer Zamski, David WeissAbstract:Previous studies have suggested that gibberellins (GAs) are produced in petunia Anthers and transported to the corolla to induce growth and pigmentation. In this work, we studied the role of GA in the regulation of anther development. When petunia plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these Anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated Anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. A similar phenotype was obtained when the Arabidopsis GA-signal repressor, SPY, was over-expressed in transgenic petunia plants, i.e. anther development was arrested following microsporogenesis. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to study GA responses. GA3 treatment of young Anthers promoted, and paclobutrazol inhibited, GIP expression, suggesting that the hormone controls the natural activation of the gene in the Anthers. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development.
János Pauk - One of the best experts on this subject based on the ideXlab platform.
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induction of in vitro androgenesis in anther and isolated microspore culture of different spelt wheat triticum spelta l genotypes
Plant Cell Tissue and Organ Culture, 2018Co-Authors: Csaba Lantos, Lajos Bóna, Eva Nagy, Ferenc Bekes, János PaukAbstract:This is the first report on isolated microspore culture—derived spelt wheat. The efficiency of anther- and isolated microspore was compared using four genotypes (‘Franckenkorn’, ‘GK Feher’, ‘Mv Martongold’, ‘Oberkulmer Rotkorn’). In anther culture, genotype dependency was observed, and cold pre-treatment enhanced the efficiency of the method. In isolated microspore culture, the ovary co-culture supported the development of embryo-like structures. The presence of growth regulators (0.5 mg/l 2,4-D and 0.5 mg/l kinetin) were not essential for the induction of androgenesis, but these increased the production of embryo-like structures, green and albino plantlets. The low plant regeneration rate and high number of albinos hinder the practical application of isolated microspore culture while anther culture was efficient for in vitro green plantlets production in spelt wheat. The mean of green plantlets production was 41.45/100 Anthers (from 20.93 to 83.07 depending on genotype). The phenomenon of albinism was mitigated in anther culture (3.48 albinos/100 Anthers). Altogether, 1720 anther culture—derived green plantlets were produced from the four genotypes.
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Comparative analysis of in vitro anther- and isolated microspore culture in hexaploid Triticale (X Triticosecale Wittmack) for androgenic parameters
Euphytica, 2014Co-Authors: Csaba Lantos, Krisztina Boda, Lajos Bóna, János PaukAbstract:Two haploid induction media (190-0 and W14mi) were tested in isolated microspore culture of two triticale (X Triticosecale Wittmack) genotypes. The W14mi medium proved superior for the production of green plantlets in both genotypes. This basic medium (W14) was used to compare two doubled haploid production methods (isolated microspore culture and anther culture) with the same genotypes. The induction of androgenesis was more effective in isolated microspore culture than in anther culture. The number of embryo-like structures was 9.2 times higher in microspore culture (511.0/100 Anthers) compared to anther culture (55.5/100 Anthers) and the number of regenerant plantlets was also 3.4 times higher (anther culture—20.15/100 Anthers; isolated microspore culture—67.6/100 Anthers). However, the regenerant plantlets from isolated microspore culture were mainly albinos while predominantly green plantlets were regenerated from anther culture. The production of green plantlets from anther culture (16.8/100 Anthers) was 2.9 times higher than from isolated microspore culture (5.8/100 Anthers). The efficiency of anther culture was tested with eight winter triticale genotypes. The phenomenon of albinism did not hinder the green plant production in anther culture. Mean green plantlet production was 10.87/100 Anthers. This value was two times higher than the number of albinos (5.01/100 Anthers) and higher than previously published reports. The anther culture protocol described in this study is an efficient tool for the production of microspore-derived green plantlets in triticale.
Anat Izhaki - One of the best experts on this subject based on the ideXlab platform.
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gibberellin regulates post microsporogenesis processes in petunia Anthers
Physiologia Plantarum, 2002Co-Authors: Anat Izhaki, Amihud Borochov, Eliezer Zamski, David WeissAbstract:Previous studies have suggested that gibberellins (GAs) are produced in petunia Anthers and transported to the corolla to induce growth and pigmentation. In this work, we studied the role of GA in the regulation of anther development. When petunia plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these Anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated Anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. A similar phenotype was obtained when the Arabidopsis GA-signal repressor, SPY, was over-expressed in transgenic petunia plants, i.e. anther development was arrested following microsporogenesis. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to study GA responses. GA3 treatment of young Anthers promoted, and paclobutrazol inhibited, GIP expression, suggesting that the hormone controls the natural activation of the gene in the Anthers. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development.
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Gibberellin regulates post‐microsporogenesis processes in petunia Anthers
Physiologia plantarum, 2002Co-Authors: Anat Izhaki, Amihud Borochov, Eliezer Zamski, David WeissAbstract:Previous studies have suggested that gibberellins (GAs) are produced in petunia Anthers and transported to the corolla to induce growth and pigmentation. In this work, we studied the role of GA in the regulation of anther development. When petunia plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these Anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated Anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. A similar phenotype was obtained when the Arabidopsis GA-signal repressor, SPY, was over-expressed in transgenic petunia plants, i.e. anther development was arrested following microsporogenesis. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to study GA responses. GA3 treatment of young Anthers promoted, and paclobutrazol inhibited, GIP expression, suggesting that the hormone controls the natural activation of the gene in the Anthers. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development.
Csaba Lantos - One of the best experts on this subject based on the ideXlab platform.
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induction of in vitro androgenesis in anther and isolated microspore culture of different spelt wheat triticum spelta l genotypes
Plant Cell Tissue and Organ Culture, 2018Co-Authors: Csaba Lantos, Lajos Bóna, Eva Nagy, Ferenc Bekes, János PaukAbstract:This is the first report on isolated microspore culture—derived spelt wheat. The efficiency of anther- and isolated microspore was compared using four genotypes (‘Franckenkorn’, ‘GK Feher’, ‘Mv Martongold’, ‘Oberkulmer Rotkorn’). In anther culture, genotype dependency was observed, and cold pre-treatment enhanced the efficiency of the method. In isolated microspore culture, the ovary co-culture supported the development of embryo-like structures. The presence of growth regulators (0.5 mg/l 2,4-D and 0.5 mg/l kinetin) were not essential for the induction of androgenesis, but these increased the production of embryo-like structures, green and albino plantlets. The low plant regeneration rate and high number of albinos hinder the practical application of isolated microspore culture while anther culture was efficient for in vitro green plantlets production in spelt wheat. The mean of green plantlets production was 41.45/100 Anthers (from 20.93 to 83.07 depending on genotype). The phenomenon of albinism was mitigated in anther culture (3.48 albinos/100 Anthers). Altogether, 1720 anther culture—derived green plantlets were produced from the four genotypes.
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Comparative analysis of in vitro anther- and isolated microspore culture in hexaploid Triticale (X Triticosecale Wittmack) for androgenic parameters
Euphytica, 2014Co-Authors: Csaba Lantos, Krisztina Boda, Lajos Bóna, János PaukAbstract:Two haploid induction media (190-0 and W14mi) were tested in isolated microspore culture of two triticale (X Triticosecale Wittmack) genotypes. The W14mi medium proved superior for the production of green plantlets in both genotypes. This basic medium (W14) was used to compare two doubled haploid production methods (isolated microspore culture and anther culture) with the same genotypes. The induction of androgenesis was more effective in isolated microspore culture than in anther culture. The number of embryo-like structures was 9.2 times higher in microspore culture (511.0/100 Anthers) compared to anther culture (55.5/100 Anthers) and the number of regenerant plantlets was also 3.4 times higher (anther culture—20.15/100 Anthers; isolated microspore culture—67.6/100 Anthers). However, the regenerant plantlets from isolated microspore culture were mainly albinos while predominantly green plantlets were regenerated from anther culture. The production of green plantlets from anther culture (16.8/100 Anthers) was 2.9 times higher than from isolated microspore culture (5.8/100 Anthers). The efficiency of anther culture was tested with eight winter triticale genotypes. The phenomenon of albinism did not hinder the green plant production in anther culture. Mean green plantlet production was 10.87/100 Anthers. This value was two times higher than the number of albinos (5.01/100 Anthers) and higher than previously published reports. The anther culture protocol described in this study is an efficient tool for the production of microspore-derived green plantlets in triticale.