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William G T Willats - One of the best experts on this subject based on the ideXlab platform.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    Annals of Botany, 2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    BACKGROUND AND AIMS: The production of multicellular gametangia in green plants represents an early evolutionary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. METHODS: Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. KEY RESULTS: Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. CONCLUSIONS: Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous in the Antheridium, the distribution of arabinogalactan protein and xyloglucan epitopes is restricted to specific zones. Spermatogenesis also includes a major switch in the production of extracellular matrix macromolecules from cell walls to scales, the latter being a primitive extracellular matrix characteristic of green plants.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    †Background and Aims The production of multicellular gametangia in green plants represents an early evolution-ary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. †Methods Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. †Key Results Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. †Conclusions Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous i

Motomi Ito - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of sexual reproductive processes in Chara braunii (Charales, Charophyceae)
    Phycological Research, 2014
    Co-Authors: Machiko Sato, Mamiko Sato, Motomi Ito, Hiroyuki Sekimoto
    Abstract:

    Summary Chara braunii is distributed worldwide and is the most common charalean species in Japan. This species is monoecious and produces numerous sets of sex organs, each of which consists of one Antheridium and one oogonium, under laboratory culture conditions. In this study, we report that light intensity strongly affected the vegetative phase and sexual reproductive phase of this species. Under high-light conditions (70.0 μmol photons m−2 s−1), thalli grew but did not form reproductive organs. Under a low-light intensity (10.0 μmol photons m−2 s−1), algal bodies formed many reproductive organs. In addition, antheridia without the corresponding oogonia (lone antheridia) were observed under low-light conditions. The absence of oogonium primordia adjacent to the lone Antheridium was confirmed by several microscopic approaches. The addition of liquid fertilizer increased the total number of sex organs and growth; however, the number of lone antheridia decreased with increasing fertilizer concentrations. Exogenously applied gibberellin did not affect the number of lone antheridia. These results suggest that regulatory mechanisms for the appropriate allocation of resources exist in this alga, similar to those reported in some land plants.

  • Characterization of MADS-box genes in charophycean green algae and its implication for the evolution of MADS-box genes
    Proceedings of the National Academy of Sciences of the United States of America, 2005
    Co-Authors: Yoichi Tanabe, Hiroyuki Sekimoto, Mitsuyasu Hasebe, Tomoaki Nishiyama, Masakazu Kitani, Katrin Henschel, Thomas Münster, Günter Theissen, Hisayoshi Nozaki, Motomi Ito
    Abstract:

    The MADS-box genes of land plants are extensively diverged to form a superfamily and are important in various aspects of development including the specification of floral organs as homeotic selector genes. The closest relatives of land plants are the freshwater green algae charophyceans. To study the origin and evolution of land plant MADS-box genes, we characterized these genes in three charophycean green algae: the stonewort Chara globularis, the coleochaete Coleochaete scutata, and the desmid Closterium peracerosum-strigosum-littorale complex. Phylogenetic analyses suggested that MADS-box genes diverged extensively in the land plant lineage after the separation of charophyceans from land plants. The stonewort C. globularis mRNA was specifically detected in the oogonium and Antheridium together with the egg and spermatozoid during their differentiation. The expression of the C. peracerosum-strigosum-littorale-complex gene increased when vegetative cells began to differentiate into gametangial cells and decreased after fertilization. These expression patterns suggest that the precursors of land plant MADS-box genes originally functioned in haploid reproductive cell differentiation and that the haploid MADS-box genes were recruited into a diploid generation during the evolution of land plants.

David S. Domozych - One of the best experts on this subject based on the ideXlab platform.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    Annals of Botany, 2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    BACKGROUND AND AIMS: The production of multicellular gametangia in green plants represents an early evolutionary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. METHODS: Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. KEY RESULTS: Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. CONCLUSIONS: Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous in the Antheridium, the distribution of arabinogalactan protein and xyloglucan epitopes is restricted to specific zones. Spermatogenesis also includes a major switch in the production of extracellular matrix macromolecules from cell walls to scales, the latter being a primitive extracellular matrix characteristic of green plants.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    †Background and Aims The production of multicellular gametangia in green plants represents an early evolution-ary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. †Methods Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. †Key Results Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. †Conclusions Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous i

Stephen A Johnston - One of the best experts on this subject based on the ideXlab platform.

  • ecologically based approaches to management of phytophthora blight on bell pepper
    Plant Disease, 1999
    Co-Authors: J B Ristaino, Stephen A Johnston
    Abstract:

    Phytophthora blight, caused by the oomycete pathogen, Phytophthora capsici, is a devastating disease on bell pepper and cucurbit crops in the United States and worldwide (29,40). P. capsici causes a root and crown rot, as well as an aerial blight of leaves, fruit, and stems, on bell pepper (Capsicum annuum), tomatoes, cucumber, watermelon, squash, and pumpkin (29,35, 40,57,73). The disease was first described on bell pepper in New Mexico in 1922 (40). In recent years, epidemics have been severe in areas of North Carolina, Florida, Georgia, Michigan, and New Jersey. Oospores are believed to provide the initial source of inoculum in the field, and the disease is polycyclic within seasons (1,7,59,60,67). In this article, we discuss the biology and epidemiology of Phytophthora blight on bell pepper and also describe management strategies that can be implemented based on existing knowledge of the ecology of this devastating pathogen. The objectives of ecologically based pest management (EBPM) are the safe, profitable, and durable management of pests that includes a total systems approach (25). EBPM relies primarily on biological input of knowledge concerning a pathogen life cycle, and secondarily, when necessary, on physical, chemical, and biological supplements for disease management. An understanding of the ecological processes that are suppressive to plant diseases is emphasized rather than secondary inputs (25). Fortunately, we have a considerable amount of information available on the biology and ecology of P. capsici, which can now be integrated to improve our ability to manage the disease using ecologically based approaches. Strategies recommended for management of Phytophthora blight involve integrated approaches that focus first on cultural practices that reduce high soil moisture conditions, but also include monitoring and reduction of propagules of P. capsici that persist in the soil, utilization of cultivars with resistance to the disease, and when necessary, judicious fungicide applications. Symptoms and Life Cycle P. capsici can infect virtually every part of the pepper plant. The pathogen causes a root and crown rot on pepper (Fig. 1) and also forms distinctive black lesions on the stem (Fig. 2). P. capsici can also infect the leaves and causes lesions that are circular, grayish brown, and water-soaked (Fig. 3). Leaf lesions and stem lesions are common when inoculum is splash dispersed from the soil to lower portions of the plant. The pathogen can also infect fruit and causes lesions that are typically covered with white sporangia, a sign of the pathogen (Fig. 4). P. capsici typically causes a fruit rot or stem rot on cucumbers and squash (Fig. 5). P. capsici reproduces by both sexual and asexual means (Fig. 6). The pathogen produces two mating types, known as the A1 and A2. These are actually compatibility types and do not correspond to dimorphic forms. Each mating type produces hormones that are responsible for gametangia differentiation in the opposite mating type. Both A1 and A2 mating types are common in fields in North Carolina and have also been identified within the same plant (59). P. capsici produces a male gametangium, called the Antheridium, and a female gametangium, called the oogonium. The Antheridium is amphigynous in this species. Meiosis occurs within the gametangia, and plasmogamy and karyogamy result

  • Ecologically Based Approaches to Management of Phytophthora Blight on Bell Pepper
    Plant disease, 1999
    Co-Authors: J B Ristaino, Stephen A Johnston
    Abstract:

    Phytophthora blight, caused by the oomycete pathogen, Phytophthora capsici, is a devastating disease on bell pepper and cucurbit crops in the United States and worldwide (29,40). P. capsici causes a root and crown rot, as well as an aerial blight of leaves, fruit, and stems, on bell pepper (Capsicum annuum), tomatoes, cucumber, watermelon, squash, and pumpkin (29,35, 40,57,73). The disease was first described on bell pepper in New Mexico in 1922 (40). In recent years, epidemics have been severe in areas of North Carolina, Florida, Georgia, Michigan, and New Jersey. Oospores are believed to provide the initial source of inoculum in the field, and the disease is polycyclic within seasons (1,7,59,60,67). In this article, we discuss the biology and epidemiology of Phytophthora blight on bell pepper and also describe management strategies that can be implemented based on existing knowledge of the ecology of this devastating pathogen. The objectives of ecologically based pest management (EBPM) are the safe, profitable, and durable management of pests that includes a total systems approach (25). EBPM relies primarily on biological input of knowledge concerning a pathogen life cycle, and secondarily, when necessary, on physical, chemical, and biological supplements for disease management. An understanding of the ecological processes that are suppressive to plant diseases is emphasized rather than secondary inputs (25). Fortunately, we have a considerable amount of information available on the biology and ecology of P. capsici, which can now be integrated to improve our ability to manage the disease using ecologically based approaches. Strategies recommended for management of Phytophthora blight involve integrated approaches that focus first on cultural practices that reduce high soil moisture conditions, but also include monitoring and reduction of propagules of P. capsici that persist in the soil, utilization of cultivars with resistance to the disease, and when necessary, judicious fungicide applications. Symptoms and Life Cycle P. capsici can infect virtually every part of the pepper plant. The pathogen causes a root and crown rot on pepper (Fig. 1) and also forms distinctive black lesions on the stem (Fig. 2). P. capsici can also infect the leaves and causes lesions that are circular, grayish brown, and water-soaked (Fig. 3). Leaf lesions and stem lesions are common when inoculum is splash dispersed from the soil to lower portions of the plant. The pathogen can also infect fruit and causes lesions that are typically covered with white sporangia, a sign of the pathogen (Fig. 4). P. capsici typically causes a fruit rot or stem rot on cucumbers and squash (Fig. 5). P. capsici reproduces by both sexual and asexual means (Fig. 6). The pathogen produces two mating types, known as the A1 and A2. These are actually compatibility types and do not correspond to dimorphic forms. Each mating type produces hormones that are responsible for gametangia differentiation in the opposite mating type. Both A1 and A2 mating types are common in fields in North Carolina and have also been identified within the same plant (59). P. capsici produces a male gametangium, called the Antheridium, and a female gametangium, called the oogonium. The Antheridium is amphigynous in this species. Meiosis occurs within the gametangia, and plasmogamy and karyogamy result

Iben Sørensen - One of the best experts on this subject based on the ideXlab platform.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    Annals of Botany, 2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    BACKGROUND AND AIMS: The production of multicellular gametangia in green plants represents an early evolutionary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. METHODS: Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. KEY RESULTS: Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. CONCLUSIONS: Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous in the Antheridium, the distribution of arabinogalactan protein and xyloglucan epitopes is restricted to specific zones. Spermatogenesis also includes a major switch in the production of extracellular matrix macromolecules from cell walls to scales, the latter being a primitive extracellular matrix characteristic of green plants.

  • The distribution of cell wall polymers during Antheridium development and spermatogenesis in the Charophycean green alga, Chara corallina
    2009
    Co-Authors: David S. Domozych, Iben Sørensen, William G T Willats
    Abstract:

    †Background and Aims The production of multicellular gametangia in green plants represents an early evolution-ary development that is found today in all land plants and advanced clades of the Charophycean green algae. The processing of cell walls is an integral part of this morphogenesis yet very little is known about cell wall dynamics in early-divergent green plants such as the Charophycean green algae. This study represents a comprehensive analysis of Antheridium development and spermatogenesis in the green alga, Chara corallina. †Methods Microarrays of cell wall components and immunocytochemical methods were employed in order to analyse cell wall macromolecules during Antheridium development. †Key Results Cellulose and pectic homogalacturonan epitopes were detected throughout all cell types of the developing Antheridium including the unique cell wall protuberances of the shield cells and the cell walls of sperm cell initials. Arabinogalactan protein epitopes were distributed only in the epidermal shield cell layers and anti-xyloglucan antibody binding was only observed in the capitulum region that initially yields the sperm filaments. During the terminal stage of sperm development, no cell wall polymers recognized by the probes employed were found on the scale-covered sperm cells. †Conclusions Antheridium development in C. corallina is a rapid event that includes the production of cell walls that contain polymers similar to those found in land plants. While pectic and cellulosic epitopes are ubiquitous i