Genome Engineering for Crop Improvement. Группа авторов
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Название: Genome Engineering for Crop Improvement

Автор: Группа авторов

Издательство: John Wiley & Sons Limited

Жанр: Биология

Серия:

isbn: 9781119672401

isbn:

СКАЧАТЬ et al. 2017; Rodrigues et al. 2018).

Schematic illustration of quantitative mineral-element distribution maps of a Tartary buckwheat grain cross-section, comprising centrally-positioned cotyledons surrounding the endosperm and the pericarp as obtained by micro-PIXE and described previously.

      Synchrotron micro‐X‐ray fluorescence was, for example, used to determine the in vivo mineral distribution patterns in rice (Oryza sativa) grains and shifts in these distribution patterns during progressive germination stages. The results of bulk analyses of hulled, brown and polished rice showed that half of the total Zn, two thirds of the total Fe and most of the total K, Ca, and Mn were removed by the milling process when the hull and bran were thoroughly polished. The concentrations of all elements were high in the regions of the embryo, though local distributions within the embryo varied between the elements. The mobilization of minerals from certain seed locations during germination was also element specific. A high mobilization of K and Ca from the grains to the growing roots and leaf primordia was observed; the flow of Zn to these expanding tissues was slightly lower than that of K and Ca; the mobilization of Mn or Fe was relatively low, at least during the first days of germination (Lu et al. 2013).

      Understanding the spatial distribution of inorganic nutrients within edible parts of plant products helps biofortification efforts to identify and focus on specific uptake pathways and storage mechanisms. Thus, the distribution of inorganic nutrients was studied in maize and sweetcorn. The results show that localization of elements is largely similar between maize and sweetcorn, but defer markedly depending upon the maturity stage after further embryonic development. The micronutrients Zn, Fe, and Mn accumulated primarily in the scutellum of the embryo during early kernel development, while trace amounts of these were found in the aleurone layer at the mature stage. Though P accumulated in the scutellum, there was no direct relationship between the concentrations of P and those of the micronutrients, compared to the linear trend between Zn and Fe concentrations (Cheah et al. 2019).

      In a more detailed analysis of wheat aleurone, synchrotron radiation soft X‐ray full‐field imaging mode (FFIM) provided detailed images of globoids covered by oleosomes. Low‐energy X‐ray fluorescence (LEXRF) spectro‐microscopy showed that these structural features were connected to subcellular distribution of elements (Zn, Fe, Na, Mg, Al, Si, and P)(Regvar et al. 2011). This evidence suggest that membranous globular structures provide a basic structural scaffold for deposition on mineral elements within the aleurone cells and most likely affect their bioavailability.

Schematic illustration of element (K, Ca, Fe, Mn, and Zn) localization in Khorasan wheat (Triticum turgidum ssp. turanicum) by micro-XRF, Synchrotron Light Research Institute, Thailand, lateral resolution 50 micrometers, step size 50 micrometers, polychromatic excitation, data fitted by PyMCA.

      LA‐ICPMS was used to map the Zn localization in durum wheat at different nitrogen supply (Persson et al. 2016). Elemental distribution imaging was combined with the analysis of Zn‐binding proteins by liquid chromatography ICPMS and orbitrap MS. The increase in Zn and N supply had a major impact on the Zn concentration in the endosperm and reached concentrations higher than current breeding targets. The sulfur concentration also increased, but S was only partially co‐localized with Zn. The mutual accumulation of Zn and S was reflected in much more Zn bound to small cysteine‐rich proteins (apparent size, 10–30 kDa), while the response of larger proteins (apparent size, 50 kDa) was only moderate. Most Zn‐reactive proteins were associated with redox and stress processes.

Photos depict LA-ICPMS images of the Ca and K distribution in the maize kernel. The lateral resolution is 50 micrometers.

      Nano Secondary Ion MS (nano SIMS) works based on a coaxial optical design of the ion gun and secondary ion extraction, and on an original magnetic sector mass spectrometer with multicollection. Nano SIMS fills a unique niche as an MS tool for biological analysis by providing unmatched lateral resolution of elemental and isotopic distributions in samples of interest (Nuñez et al. 2018).