It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
SUMMARYOrchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in... more SUMMARYOrchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in all orchid species carbon is provided to the host plant by the mycorrhizal fungus at least during the early stages of orchid development, named a protocorm. In addition to carbon, orchid mycorrhizal fungi provide the host plant with essential nutrients such as phosphorus and nitrogen. In mycorrhizal protocorms, nutrients transfer occurs in plant cells colonized by the intracellular fungal coils, or pelotons. Whereas the transfer of these vital nutrients to the orchid protocorm in the OM symbiosis has been already investigated, there is currently no information on the transfer of sulfur (S). Here, we used ultra‐high spatial resolution secondary ion mass spectrometry (SIMS) as well as targeted gene expression studies and laser microdissection to decipher S metabolism and transfer in the model system formed by the Mediterranean orchid Serapias vomeracea and the mycorrhizal fungus Tulasnell...
It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
With regard to life sciences, it is important to understand biological functions such as metaboli... more With regard to life sciences, it is important to understand biological functions such as metabolic reactions at the cellular level. Time-offlight secondary ion mass spectrometry (TOF-SIMS) that can provide chemical mappings at 100 nm lateral resolutions is useful for obtaining three-dimensional maps of biological molecules in cells and tissues. TOF-SIMS spectra generally contain several hundred to several thousand secondary ion peaks that provide detailed chemical information. In order to manage such a large number of peaks, data analysis methods such as multivariate analysis techniques have been applied to TOF-SIMS data of complex samples. However, the interpretation of the data analysis results is sometimes still difficult, especially for biological samples. In this study, TOF-SIMS data of resin-embedded plant samples were analyzed using one of the sparse modeling methods, least absolute shrinkage and selection operator (LASSO), to directly select secondary ions related to biological structures such as cell walls and nuclei. The same sample was measured by optical microscopy and the same measurement area as TOF-SIMS was extracted in order to prepare a target image for LASSO. The same area of the TOF-SIMS and microscope data were fused to evaluate the influence of the image fusion on the TOF-SIMS spectrum information using principal component analysis. Specifically, the authors examined onion mycorrhizal root colonized with Gigaspora margarita (an arbuscular mycorrhizal fungus). The results showed that by employing this approach using LASSO, important secondary ions from biological samples were effectively selected and could be clearly distinguished from the embedding resin.
Inorganic polyphosphate (poly P) is a linear polymer of orthophosphate and has many biological fu... more Inorganic polyphosphate (poly P) is a linear polymer of orthophosphate and has many biological functions in prokaryotic and eukaryotic organisms. To investigate poly P localization, we developed a novel technique using the affinity of the recombinant polyphosphate binding domain (PPBD) of Escherichia coli exopolyphosphatase to poly P. An epitope-tagged PPBD was expressed and purified from E. coli. Equilibrium-binding assay of PPBD revealed its high affinity for long-chain poly P and its weak affinity for short-chain poly P and nucleic acids. To directly demonstrate poly P localization in Saccharomyces cerevisiae on resin sections prepared by rapid-freeze and freeze-substitution, specimens were labeled with PPBD containing an epitope tag, and then the epitope tag was detected by an indirect immunocytochemical method. A goat anti-mouse IgG antibody conjugated with Alexa 488 for laser confocal microscopy or with colloidal gold for transmission electron microscopy was used. When the S. ...
The microbes in the rhizosphere constitute very complex communities, in which some are beneficial... more The microbes in the rhizosphere constitute very complex communities, in which some are beneficial, others are pathogenic, but the vast majority of microbes are neutral commensals. Methods to unravel the interactions between roots and rhizospheric microbes have involved genetic approaches to determine the molecular bases of plant-microbe recognition and specific adaptive programs for either symbiosis or defense. In addition, imaging techniques have become particularly important to describe and understand the processes that occur within the spatially highly complex environments in and around the roots. Recently developed imaging techniques, in conjunction with appropriate labeling procedures, allow to address functional questions involving tissue-specific gene expression and elemental fluxes in the interactions between roots and rhizospheric microbes. Here, we discuss several imaging techniques from in situ hybridization, that allows the visualization of plant and microbial transcript...
The objective of this study was to elucidate the transfer of nutrient elements in orchid symbioti... more The objective of this study was to elucidate the transfer of nutrient elements in orchid symbiotic protocorms at the cellular level by imaging of stable isotope tracers. We address the long-standing question of whether nutrients move by transport across the symbiotic interface or solely by lysis of fungal pelotons. [U-13 C]glucose and 15 NH 4 15 NO 3 were added to Ceratobasidium sp. hyphae extending from symbiotic protocorms of Spiranthes sinensis. Isotope images were taken from resin-embedded sections of protocorms using ultra-high spatial resolution secondary ion mass spectrometry (SIMS). Analyses of regions of interest were conducted on isotope ratio images for fungal and host structures. Amyloplasts adjacent to young pelotons showed elevated 13 C/ 12 C, which indicated that fungal carbon (C) was transferred from live hyphae. Senescent pelotons and their surrounding host cytoplasm showed significantly higher isotope ratios than young pelotons and surrounding host cytoplasm. These results indicate an inflow of C to senescent hyphae, which was then transferred to the host. The findings of this study provide some support for each of the two contradictory hypotheses concerning nutrient exchange in the symbiotic protocorm: the interface between the symbionts is involved before fungal senescence, and peloton degradation also releases a significant amount of C and nitrogen to host cells.
Double-stranded (ds)RNA of various types was detected in 65 (21.8%) of 298 isolates from vegetati... more Double-stranded (ds)RNA of various types was detected in 65 (21.8%) of 298 isolates from vegetative hyphae of Rosellinia necatrix by electrophoresis, but dsRNA was not detected from 39 ascosporic isolates. There were 45 distinct dsRNA profiles in the 65 isolates: they varied in the number of electrophoretic bands from 1 to 12 and in size from less than 1000 bp
A root box method with carrots was developed to estimate virulence of the violet root rot fungu... more A root box method with carrots was developed to estimate virulence of the violet root rot fungus, Helicobasidium mompa, to facilitate short-term screening of many isolates during a year. The root box consisted of two transparent acrylic plates and a plastic bag of vermiculite in which two taproots of carrot were growing and inoculated with the fungus growing on fragments
Arbuscular mycorrhizal (AM) fungi can improve plant tolerance to heavy metal contamination. This ... more Arbuscular mycorrhizal (AM) fungi can improve plant tolerance to heavy metal contamination. This detoxification ability may largely depend on how AM fungi influence the uptake and distribution of metals in host plants. Two experiments were performed in order to gain insights into the mechanisms underlying cadmium (Cd) tolerance in mycorrhizal plants. Stable isotope Cd and compartmented pots were adopted to quantify the contribution of the AM fungus, Rhizophagus irregularis, to the uptake of Cd by Lotus japonicus. Moreover, synchrotron radiation μX-ray fluorescence (SR-μXRF) was applied to localize Cd in the mycorrhizal roots at the sub-cellular level. The results obtained indicated that mycorrhizal colonization markedly enhanced Cd immobilization in plant roots. Less Cd was partitioned to plant shoots when only hyphae had access to Cd in the hyphal compartment than when roots also had direct access to the Cd pool. SR-μXRF imaging indicated that Cd absorbed by extraradical hyphae was...
It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
SUMMARYOrchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in... more SUMMARYOrchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in all orchid species carbon is provided to the host plant by the mycorrhizal fungus at least during the early stages of orchid development, named a protocorm. In addition to carbon, orchid mycorrhizal fungi provide the host plant with essential nutrients such as phosphorus and nitrogen. In mycorrhizal protocorms, nutrients transfer occurs in plant cells colonized by the intracellular fungal coils, or pelotons. Whereas the transfer of these vital nutrients to the orchid protocorm in the OM symbiosis has been already investigated, there is currently no information on the transfer of sulfur (S). Here, we used ultra‐high spatial resolution secondary ion mass spectrometry (SIMS) as well as targeted gene expression studies and laser microdissection to decipher S metabolism and transfer in the model system formed by the Mediterranean orchid Serapias vomeracea and the mycorrhizal fungus Tulasnell...
It is with great appreciation that we acknowledge the following reviewers who have served our res... more It is with great appreciation that we acknowledge the following reviewers who have served our research community by reviewing manuscripts for Nutrients in 2011.
With regard to life sciences, it is important to understand biological functions such as metaboli... more With regard to life sciences, it is important to understand biological functions such as metabolic reactions at the cellular level. Time-offlight secondary ion mass spectrometry (TOF-SIMS) that can provide chemical mappings at 100 nm lateral resolutions is useful for obtaining three-dimensional maps of biological molecules in cells and tissues. TOF-SIMS spectra generally contain several hundred to several thousand secondary ion peaks that provide detailed chemical information. In order to manage such a large number of peaks, data analysis methods such as multivariate analysis techniques have been applied to TOF-SIMS data of complex samples. However, the interpretation of the data analysis results is sometimes still difficult, especially for biological samples. In this study, TOF-SIMS data of resin-embedded plant samples were analyzed using one of the sparse modeling methods, least absolute shrinkage and selection operator (LASSO), to directly select secondary ions related to biological structures such as cell walls and nuclei. The same sample was measured by optical microscopy and the same measurement area as TOF-SIMS was extracted in order to prepare a target image for LASSO. The same area of the TOF-SIMS and microscope data were fused to evaluate the influence of the image fusion on the TOF-SIMS spectrum information using principal component analysis. Specifically, the authors examined onion mycorrhizal root colonized with Gigaspora margarita (an arbuscular mycorrhizal fungus). The results showed that by employing this approach using LASSO, important secondary ions from biological samples were effectively selected and could be clearly distinguished from the embedding resin.
Inorganic polyphosphate (poly P) is a linear polymer of orthophosphate and has many biological fu... more Inorganic polyphosphate (poly P) is a linear polymer of orthophosphate and has many biological functions in prokaryotic and eukaryotic organisms. To investigate poly P localization, we developed a novel technique using the affinity of the recombinant polyphosphate binding domain (PPBD) of Escherichia coli exopolyphosphatase to poly P. An epitope-tagged PPBD was expressed and purified from E. coli. Equilibrium-binding assay of PPBD revealed its high affinity for long-chain poly P and its weak affinity for short-chain poly P and nucleic acids. To directly demonstrate poly P localization in Saccharomyces cerevisiae on resin sections prepared by rapid-freeze and freeze-substitution, specimens were labeled with PPBD containing an epitope tag, and then the epitope tag was detected by an indirect immunocytochemical method. A goat anti-mouse IgG antibody conjugated with Alexa 488 for laser confocal microscopy or with colloidal gold for transmission electron microscopy was used. When the S. ...
The microbes in the rhizosphere constitute very complex communities, in which some are beneficial... more The microbes in the rhizosphere constitute very complex communities, in which some are beneficial, others are pathogenic, but the vast majority of microbes are neutral commensals. Methods to unravel the interactions between roots and rhizospheric microbes have involved genetic approaches to determine the molecular bases of plant-microbe recognition and specific adaptive programs for either symbiosis or defense. In addition, imaging techniques have become particularly important to describe and understand the processes that occur within the spatially highly complex environments in and around the roots. Recently developed imaging techniques, in conjunction with appropriate labeling procedures, allow to address functional questions involving tissue-specific gene expression and elemental fluxes in the interactions between roots and rhizospheric microbes. Here, we discuss several imaging techniques from in situ hybridization, that allows the visualization of plant and microbial transcript...
The objective of this study was to elucidate the transfer of nutrient elements in orchid symbioti... more The objective of this study was to elucidate the transfer of nutrient elements in orchid symbiotic protocorms at the cellular level by imaging of stable isotope tracers. We address the long-standing question of whether nutrients move by transport across the symbiotic interface or solely by lysis of fungal pelotons. [U-13 C]glucose and 15 NH 4 15 NO 3 were added to Ceratobasidium sp. hyphae extending from symbiotic protocorms of Spiranthes sinensis. Isotope images were taken from resin-embedded sections of protocorms using ultra-high spatial resolution secondary ion mass spectrometry (SIMS). Analyses of regions of interest were conducted on isotope ratio images for fungal and host structures. Amyloplasts adjacent to young pelotons showed elevated 13 C/ 12 C, which indicated that fungal carbon (C) was transferred from live hyphae. Senescent pelotons and their surrounding host cytoplasm showed significantly higher isotope ratios than young pelotons and surrounding host cytoplasm. These results indicate an inflow of C to senescent hyphae, which was then transferred to the host. The findings of this study provide some support for each of the two contradictory hypotheses concerning nutrient exchange in the symbiotic protocorm: the interface between the symbionts is involved before fungal senescence, and peloton degradation also releases a significant amount of C and nitrogen to host cells.
Double-stranded (ds)RNA of various types was detected in 65 (21.8%) of 298 isolates from vegetati... more Double-stranded (ds)RNA of various types was detected in 65 (21.8%) of 298 isolates from vegetative hyphae of Rosellinia necatrix by electrophoresis, but dsRNA was not detected from 39 ascosporic isolates. There were 45 distinct dsRNA profiles in the 65 isolates: they varied in the number of electrophoretic bands from 1 to 12 and in size from less than 1000 bp
A root box method with carrots was developed to estimate virulence of the violet root rot fungu... more A root box method with carrots was developed to estimate virulence of the violet root rot fungus, Helicobasidium mompa, to facilitate short-term screening of many isolates during a year. The root box consisted of two transparent acrylic plates and a plastic bag of vermiculite in which two taproots of carrot were growing and inoculated with the fungus growing on fragments
Arbuscular mycorrhizal (AM) fungi can improve plant tolerance to heavy metal contamination. This ... more Arbuscular mycorrhizal (AM) fungi can improve plant tolerance to heavy metal contamination. This detoxification ability may largely depend on how AM fungi influence the uptake and distribution of metals in host plants. Two experiments were performed in order to gain insights into the mechanisms underlying cadmium (Cd) tolerance in mycorrhizal plants. Stable isotope Cd and compartmented pots were adopted to quantify the contribution of the AM fungus, Rhizophagus irregularis, to the uptake of Cd by Lotus japonicus. Moreover, synchrotron radiation μX-ray fluorescence (SR-μXRF) was applied to localize Cd in the mycorrhizal roots at the sub-cellular level. The results obtained indicated that mycorrhizal colonization markedly enhanced Cd immobilization in plant roots. Less Cd was partitioned to plant shoots when only hyphae had access to Cd in the hyphal compartment than when roots also had direct access to the Cd pool. SR-μXRF imaging indicated that Cd absorbed by extraradical hyphae was...
Uploads
Papers by Yukari Kuga