The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Hans J. Bohnert - One of the best experts on this subject based on the ideXlab platform.
-
Molecular Mechanisms of Salinity Tolerance
2014Co-Authors: Es Company, Hans J. Bohnert, Bo ShenAbstract:Plants have evolved complex mechanisms allowing for adaptation to osmotic stress causedby drought and to osmotic and ionic stress caused by high salinity. These mechanisms can be classified into two categories: One includes developmental, morphological, and physiological mechanisms; the other includes biochemical mechanisms. Developmental, morphological, and physiological mechanisms are usually complex and require the functions of many gene products. Examples of complex changes initiated by stress are the switch from the C3 photosynthetic pathway to Crassulacean acid metabolism (CAM) in Mesembryanthemum crystallinum following salt stress,1 the development of salt glands in Limonium sp.,2 salt-storing epidermal bladder cells in Mesembryanthemum crystallinum3,4 and changes leading to increased water use efficiency in the development of the C4 photosynthetic pathway.5 Biochemical mechanisms, in contrast, are relatively simple, typically involving the action of only a few gene products. For example, the accumulation of compatible solutes, such as glycine betaine, proline, ectoine or polyols, only requires one to three enzymes for extending a main metabolic pathway into the branch pathway of metabolite accumulation.6-9 Similarly, adjustments in ion uptake seem to be controlled by an equally small number o
-
Expression of water channel proteins in Mesembryanthemum crystallinum
Plant physiology, 2000Co-Authors: Hans-hubert Kirch, Christine B. Michalowski, Rosario Vera-estrella, Dortje Golldack, Françoise Quigley, Bronwyn J. Barkla, Hans J. BohnertAbstract:We have characterized transcripts for nine major intrinsic proteins (MIPs), some of which function as water channels (aquaporins), from the ice plant Mesembryanthemum crystallinum. To determine the cellular distribution and expression of these MIPs, oligopeptide-based antibodies were generated against MIP-A, MIP-B, MIP-C, or MIP-F, which, according to sequence and functional characteristics, are located in the plasma membrane (PM) and tonoplast, respectively. MIPs were most abundant in cells involved in bulk water flow and solute flux. The tonoplast MIP-F was found in all cells, while signature cell types identified different PM-MIPs: MIP-A predominantly in phloem-associated cells, MIP-B in xylem parenchyma, and MIP-C in the epidermis and endodermis of immature roots. Membrane protein analysis confirmed MIP-F as tonoplast located. MIP-A and MIP-B were found in tonoplast fractions and also in fractions distinct from either the tonoplast or PM. MIP-C was most abundant but not exclusive to PM fractions, where it is expected based on its sequence signature. We suggest that within the cell, MIPs are mobile, which is similar to aquaporins cycling through animal endosomes. MIP cycling and the differential regulation of these proteins observed under conditions of salt stress may be fundamental for the control of tissue water flux.
-
growth and development of Mesembryanthemum crystallinum aizoaceae
New Phytologist, 1998Co-Authors: Patricia Adams, Hans J. Bohnert, Shigehiro Yamada, Richard G. Jensen, Donald E Nelson, Wendy Chmara, Howard GriffithsAbstract:This review describes the life cycle of Mesembryantheum crystallinum L. (the common ice plant, Aizoaceae, Caryophyllales), a halophyte with a developmentally programmed switch from C3 photosynthesis to Crassulacean acid metabolism (CAM) which is accelerated by salinity and drought. Since there has been controversy regarding the interplay between genes and environmental stimuli during the development of M. crystallinum, it is timely to summarize the life cycle for a defined set of conditions. We seek to establish the framework whereby five stages of development can be described in terms of morphology, physiology, and molecular biology. Stages 1 and 2, representing germination and growth of a juvenile form, show a determinate pattern of growth. Although specific genes for salt tolerance can be induced at these stages, stress early in development prevents progression to the mature form (stages 3–5) in which the plants advance to mature growth, flowering, and seed development. Growth in stage 3 is indeterminate in the absence of stress, but development and flowering are accelerated by environmental stresses, and CAM is constitutively expressed. Depending on the severity of the stress, plants start to flower (stage 4) and then die from the roots, ultimately with only seed capsules remaining viable, with salt sequestered into large epidermal bladder cells (stage 5). We highlight responses to salinity leading to compartmentation of ions and compatible solutes, turgor maintenance, and CAM. Finally, the molecular genetics of the ice plant are characterized, emphasizing selected genes and their products. We conclude with an analysis of the multiple stages of growth as an ecological adaptation to progressive stress. The initial determinate and inflexible juvenile phase provides a critical mass of plant material which supports the indeterminate, mature phase. Depending on the degree of stress, the mature form is then propelled towards flowering and seedset.
-
Responses to Salt Stress in the Halophyte Mesembryanthemum Crystallinum
Biochemical and Cellular Mechanisms of Stress Tolerance in Plants, 1994Co-Authors: Hans J. Bohnert, John C. Thomas, E. Jay Derocher, Christine B. Michalowski, Heimo Breiteneder, Dan M. Vernon, Wei Deng, Shigehiro Yamada, Richard G. JensenAbstract:The halophyte Mesembryanthemum crystallinum (common ice plant) has emerged as a model system suitable to advance our understanding of mechanisms that have evolved in a species adapted to harsh environments, characterized by drought and salt stress conditions. Here, we include a discussion of distinguishing factors of cellular and organismic responses to salt stress, the role of growth regulators, and a discussion of molecular and metabolic mechanisms employed by this plant for survival. Several mechanisms appear to be important, including acceleration of ontogeny, protection of the photosynthetic apparatus, the rapid induction of presumably osmoprotective substances, and the long-term establishment of Crassulacean Acid Metabolism (CAM). Our understanding of the causes for tolerance and resistance towards abiotic environmental stresses, salt stress in particular, has been extended to include the transfer of functionally characterized genes from M. crystallinum into other plants. The use of transgenic plants will be an essential component of future work directed at the molecular dissection of mechanisms of transcription control, mRNA-stability and developmental competence in establishing salt stress tolerance.
-
Expression of a phosphoenolpyruvate carboxylase promoter from Mesembryanthemum crystallinum is not salt-inducible in mature transgenic tobacco.
Plant molecular biology, 1993Co-Authors: John C. Cushman, Michael S. Meiners, Hans J. BohnertAbstract:The 5′ flanking region of a salt-stress-inducible, CAM-specific phosphoenolpyruvate carboxylase (PEPC) gene from the facultative halophyte Mesembryanthemum crystallinum, was fused to the β-glucuronidase (GUS) reporter gene and introduced into Nicotiana tabacum SR1. The Ppc1 promoter displayed high levels of expression in transgenic tobacco quantitatively and qualitatively similar to a full-length 35S CaMV-GUS construct. Histochemical assays revealed that the full-length Ppc1-GUS fusions expressed GUS activity in all tissues except in root tips. While tobacco is capable of utilizing the Ppc1 cis-acting regulatory regions from M. crystallinum to yield high levels of constitutive expression, this glycophyte fails to direct a stress-inducible pattern of gene expression typical of this promoter in its native, facultative halophytic host.
Bronwyn J. Barkla - One of the best experts on this subject based on the ideXlab platform.
-
Single-cell-type quantitative proteomic and ionomic analysis of epidermal bladder cells from the halophyte model plant Mesembryanthemum crystallinum to identify salt-responsive proteins
BMC plant biology, 2016Co-Authors: Bronwyn J. Barkla, Rosario Vera-estrella, Carolyn A RaymondAbstract:Background Epidermal bladder cells (EBC) are large single-celled, specialized, and modified trichomes found on the aerial parts of the halophyte Mesembryanthemum crystallinum. Recent development of a simple but high throughput technique to extract the contents from these cells has provided an opportunity to conduct detailed single-cell-type analyses of their molecular characteristics at high resolution to gain insight into the role of these cells in the salt tolerance of the plant.
-
single cell type comparative metabolomics of epidermal bladder cells from the halophyte Mesembryanthemum crystallinum
Frontiers in Plant Science, 2015Co-Authors: Bronwyn J. Barkla, Rosario VeraestrellaAbstract:One of the remarkable adaptive features of the halophyte and facultative CAM plant Mesembryathemum crystallinum are the specialized modified trichomes called epidermal bladder cells (EBC) which cover the leaves, stems, and peduncle of the plant. They are present from an early developmental stage but upon salt stress rapidly expand due to the accumulation of water and sodium. This particular plant feature makes it an attractive system for single cell type studies, with recent proteomics and transcriptomics studies of the EBC establishing that these cells are metabolically active and have roles other than sodium sequestration. To continue our investigation into the function of these unusual cells we carried out a comprehensive global analysis of the metabolites present in the EBC extract by gas chromatography Time-of-Flight mass spectrometry (GC-TOF) and identified 194 known and 722 total molecular features. Statistical analysis of the metabolic changes between control and salt-treated samples was used to identify 352 significantly differing metabolites (268 after correction for FDR). Principal components analysis provided an unbiased evaluation of the data variance structure. Biochemical pathway enrichment analysis suggested significant perturbations in 13 biochemical pathways as defined in KEGG. More than 50% of the metabolites that show significant changes in the EBC, can be classified as compatible solutes and include sugars, sugar alcohols, protein and non-protein amino acids, and organic acids, highlighting the need to maintain osmotic homeostasis to balance the accumulation of Na and Cl ions. Overall, the comparison of metabolic changes in salt treated relative to control samples suggest large alterations in Mesembryanthemum crystallinum epidermal bladder cells.
-
Expression of water channel proteins in Mesembryanthemum crystallinum
Plant physiology, 2000Co-Authors: Hans-hubert Kirch, Christine B. Michalowski, Rosario Vera-estrella, Dortje Golldack, Françoise Quigley, Bronwyn J. Barkla, Hans J. BohnertAbstract:We have characterized transcripts for nine major intrinsic proteins (MIPs), some of which function as water channels (aquaporins), from the ice plant Mesembryanthemum crystallinum. To determine the cellular distribution and expression of these MIPs, oligopeptide-based antibodies were generated against MIP-A, MIP-B, MIP-C, or MIP-F, which, according to sequence and functional characteristics, are located in the plasma membrane (PM) and tonoplast, respectively. MIPs were most abundant in cells involved in bulk water flow and solute flux. The tonoplast MIP-F was found in all cells, while signature cell types identified different PM-MIPs: MIP-A predominantly in phloem-associated cells, MIP-B in xylem parenchyma, and MIP-C in the epidermis and endodermis of immature roots. Membrane protein analysis confirmed MIP-F as tonoplast located. MIP-A and MIP-B were found in tonoplast fractions and also in fractions distinct from either the tonoplast or PM. MIP-C was most abundant but not exclusive to PM fractions, where it is expected based on its sequence signature. We suggest that within the cell, MIPs are mobile, which is similar to aquaporins cycling through animal endosomes. MIP cycling and the differential regulation of these proteins observed under conditions of salt stress may be fundamental for the control of tissue water flux.
John C. Cushman - One of the best experts on this subject based on the ideXlab platform.
-
An Agrobacterium-mediated transformation via organogenesis regeneration of a facultative CAM plant, the common ice plant Mesembryanthemum crystallinum L
Plant Production Science, 2020Co-Authors: Sakae Agarie, Makiko Umemoto, Haruki Sunagawa, Toyoaki Anai, John C. CushmanAbstract:The common ice plant, Mesembryanthemum crystallinum L. provides a useful model for the study of environmentally induced photosynthetic conversion and abiotic stresses tolerance. However, a procedur...
-
Ion accumulation and expression of ion homeostasis-related genes associated with halophilism, NaCl-promoted growth in a halophyte Mesembryanthemum crystallinum L.
Plant Production Science, 2019Co-Authors: Dan Q. Tran, John C. Cushman, Ayako Konishi, Masahiro Morokuma, Masanori Toyota, Sakae AgarieAbstract:A halophyte, the common ice plant (Mesembryanthemum crystallinum L.), shows the maximal growth under salinity, in which almost all crops die. The NaCl-stimulated growth, which is referred to as hal...
-
MYB and HD-ZIP IV homologs related to trichome formation are involved in epidermal bladder cell development in the halophyte Mesembryanthemum crystallinum L.
Plant Production Science, 2017Co-Authors: Siranet Roeurn, John C. Cushman, Narihiro Hoshino, Ken Taro Soejima, Yuuka Inoue, Sakae AgarieAbstract:The common ice plant, Mesembryanthemum crystallinum L., a halophytic new functional leafy vegetable crop, develops epidermal bladder cells (EBCs) on the surfaces of its aerial organs. Our previous ...
-
Crassulacean Acid Metabolism May Alleviate Production of Reactive Oxygen Species in a Facultative CAM Plant, the Common Ice Plant Mesembryanthemum crystallinum L.
Plant Production Science, 2010Co-Authors: Haruki Sunagawa, John C. Cushman, Sakae AgarieAbstract:We examined the function of CAM in reactive oxygen species (ROS) alleviation using a newly isolated CAM-deficient mutant of a facultative halophyte Mesembryanthemum crystallinum L. Salt-stress (0.4...
-
Efficient plant regeneration of Mesembryanthemum crystallinum via somatic embryogenesis.
Plant cell reports, 2000Co-Authors: John C. Cushman, T. Wulan, N. Kuscuoglu, M. D. SpatzAbstract:An efficient plant regeneration procedure has been established from hypocotyl explants of the common ice plant, Mesembryanthemum crystallinum L, a halophytic leaf succulent that exhibits a stress-induced switch from C3 photosynthesis to crassulacean acid metabolism (CAM). Somatic embryos were initiated and developed up to globular and heart stages in Murashige and Skoog (MS) media supplemented with 3% sucrose, 0.6% bacto-agar, 80 mM NaCl, 5 μM 2,4-D and 1 μM kinetin. High frequency regeneration occurred when somatic embryos were germinated on media that lacked 2,4-D. High cytokinin treatment suppressed normal growth of embryos and favored abnormal embryo proliferation. Without growth regulators, regenerated plants rooted on MS medium with 100% efficiency. Mature, regenerated plants were fertile and morphologically identical to seed-derived plants.
Carolyn A Raymond - One of the best experts on this subject based on the ideXlab platform.
-
Single-cell-type quantitative proteomic and ionomic analysis of epidermal bladder cells from the halophyte model plant Mesembryanthemum crystallinum to identify salt-responsive proteins
BMC plant biology, 2016Co-Authors: Bronwyn J. Barkla, Rosario Vera-estrella, Carolyn A RaymondAbstract:Background Epidermal bladder cells (EBC) are large single-celled, specialized, and modified trichomes found on the aerial parts of the halophyte Mesembryanthemum crystallinum. Recent development of a simple but high throughput technique to extract the contents from these cells has provided an opportunity to conduct detailed single-cell-type analyses of their molecular characteristics at high resolution to gain insight into the role of these cells in the salt tolerance of the plant.
Rosario Veraestrella - One of the best experts on this subject based on the ideXlab platform.
-
single cell type comparative metabolomics of epidermal bladder cells from the halophyte Mesembryanthemum crystallinum
Frontiers in Plant Science, 2015Co-Authors: Bronwyn J. Barkla, Rosario VeraestrellaAbstract:One of the remarkable adaptive features of the halophyte and facultative CAM plant Mesembryathemum crystallinum are the specialized modified trichomes called epidermal bladder cells (EBC) which cover the leaves, stems, and peduncle of the plant. They are present from an early developmental stage but upon salt stress rapidly expand due to the accumulation of water and sodium. This particular plant feature makes it an attractive system for single cell type studies, with recent proteomics and transcriptomics studies of the EBC establishing that these cells are metabolically active and have roles other than sodium sequestration. To continue our investigation into the function of these unusual cells we carried out a comprehensive global analysis of the metabolites present in the EBC extract by gas chromatography Time-of-Flight mass spectrometry (GC-TOF) and identified 194 known and 722 total molecular features. Statistical analysis of the metabolic changes between control and salt-treated samples was used to identify 352 significantly differing metabolites (268 after correction for FDR). Principal components analysis provided an unbiased evaluation of the data variance structure. Biochemical pathway enrichment analysis suggested significant perturbations in 13 biochemical pathways as defined in KEGG. More than 50% of the metabolites that show significant changes in the EBC, can be classified as compatible solutes and include sugars, sugar alcohols, protein and non-protein amino acids, and organic acids, highlighting the need to maintain osmotic homeostasis to balance the accumulation of Na and Cl ions. Overall, the comparison of metabolic changes in salt treated relative to control samples suggest large alterations in Mesembryanthemum crystallinum epidermal bladder cells.