Identification and expression profiling of Pht1 phosphate transporters in wheat in controlled environments and in the field

Phosphorus (P) is an important macronutrient with critical functions in plants. Phosphate (Pi) transporters which mediate Pi acquisition and Pi translocation within the plant are key factors in Pi deficiency responses. However, their relevance for adaptation to long-term Pi limitation under agronomic conditions, particularly in wheat, remains unknown. Here, we describe the identification of the complete Pi transporter gene family (Pht1) in wheat (Triticum aestivum). Gene expression profiles were compared for hydroponic and field-grown plant tissues of wheat at multiple developmental stages. Cis-element analysis of selected Pht1 promoter regions was performed. A broad range of expression patterns of individual TaPht1 genes was observed in relation to tissue specificity and the nutrient supply in the soil or in liquid culture, as well as an influence of the experimental system. The expression patterns indicate the involvement of specific transporters in Pi uptake, and in Pi transport and remobilization within the plant, at different growth developmental stages. Specifically, the influence of Pi nutrition indicates a complex regulatory pattern of TaPht1 gene transcript abundances as a response to low Pi availability in different culture systems, correlating with the existence of different cis-acting promoter elements

Sulphur limitation and early sulphur deficiency responses in poplar: significance of gene expression, metabolites, and plant hormones

The influence of sulphur (S) depletion on the expression of genes related to S metabolism, and on metabolite and plant hormone contents was analysed in young and mature leaves, fine roots, xylem sap, and phloem exudates of poplar (Populus tremula×Populus alba) with special focus on early consequences. S depletion was applied by a gradual decrease of sulphate availability. The observed changes were correlated with sulphate contents. Based on the decrease in sulphate contents, two phases of S depletion could be distinguished that were denominated as ‘S limitation’ and ‘early S deficiency’. S limitation was characterized by improved sulphate uptake (enhanced root-specific sulphate transporter PtaSULTR1;2 expression) and reduction capacities (enhanced adenosine 5′-phosphosulphate (APS) reductase expression) and by enhanced remobilization of sulphate from the vacuole (enhanced putative vacuolar sulphate transporter PtaSULTR4;2 expression). During early S deficiency, whole plant distribution of S was impacted, as indicated by increasing expression of the phloem-localized sulphate transporter PtaSULTR1;1 and by decreasing glutathione contents in fine roots, young leaves, mature leaves, and phloem exudates. Furthermore, at ‘early S deficiency’, expression of microRNA395 (miR395), which targets transcripts of PtaATPS3/4 (ATP sulphurylase) for cleavage, increased. Changes in plant hormone contents were observed at ‘early S deficiency’ only. Thus, S depletion affects S and plant hormone metabolism of poplar during ‘S limitation’ and ‘early S deficiency’ in a time series of events. Despite these consequences, the impact of S depletion on growth of poplar plants appears to be less severe than in Brassicaceae such as Arabidopsis thaliana or Brassica sp

Analysis of dissolving functions of insoluble phosphate by phosphorus deficiency sensitive plants

Under strongly acidic soil conditions, low phosphorus nutrition may be a factor that inhibits plant growth. We examined the effects on plant growth of adding a poorly soluble phosphate (AlPO4) under phosphorus-deficient conditions using the high-acidity resistant plants (buckwheat and kenaf) and sensitive plants (sweet basil and red clover). As a result, only buckwheat showed no inhibition of growth despite phosphorus deficiency, but the remaining three species showed reduced growth, with a particularly significant reduction seen in sweet basil. Although the growth inhibition in these species could be reversed by adding AlPO4, the extents were different according to plant species. Sweet basil, whose growth was the most inhibited by phosphorus deficiency, showed the most marked recovery in growth. When the relationship between phosphorus absorption from AlPO4 and the increase in dry weight was investigated, rates of increase in dry weight with phosphorus absorption were the highest in red clover and sweet basil, followed by buckwheat and kenaf. On the other hand, when the amounts of AlPO4 dissolubed by substances secreted from the roots were compared among these plants, AlPO4 solubility was lower in buckwheat and kenaf and higher in red clover and sweet basil. Very high AlPO4 solubility was observed in sweet basil. We conclude that plants with a higher requirement for phosphorus release greater amounts of substances that dissolution otherwise insoluble phosphates such as AlPO4 to ensure their growth

Differences of growth response to aluminum excess of two Melaleuca trees differing in aluminum resistance

Factors that inhibit the growth of plants in strongly acidic soils include low pH and aluminum excess. We evaluated two Myrtaceae species (Melaleuca cajuputi and Melaleuca bracteata), which are useful trees in tropical regions due to their resistance to low pH and excessive aluminum, to determine their response characteristics to environmental stresses. The results revealed that M.cajuputi, the growth by the aluminum concentration was not inhibited. However, the root growth of M.bracteata, by the aluminum treatment was inhibited remarkable, and 83.2% inhibited the maximum more than aluminum free. The pH of rhizosphere of both plants has decreased by the BCP plate. However, the pH decrease has decreased as for M. bracteata with high concentration of aluminum, but M.cajuputi is not changed. Next, it was able to be confirmed of aluminum accumulated in the root M.bracteata more than M.cajuputi by hematoxylin and aniline blue dyeing. At the result, it was able to be confirmed of aluminum accumulated in the root M.bracteata more than M.cajuputi. As for M.bracteata, aluminum was absorbed in the inner-cell of the root tissue. On the other hand, M.cajuputi had aluminum only in the surface of the root. We concluded that M.cajuputi was an aluminum tolerance because the mechanism that aluminum doesn't invade the internal tissue of the root was possessed

Impacts of sulphur nutrition on selenium and molybdenum concentrations in wheat grain

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Suppressive Effect of the α-Amylase Inhibitor Albumin from Buckwheat (Fagopyrum esculentum Moench) on Postprandial Hyperglycaemia

Inhibiting starch hydrolysis into sugar could reduce postprandial blood glucose elevation and contribute to diabetes prevention. Here, both buckwheat and wheat albumin that inhibited mammalian α-amylase in vitro suppressed blood glucose level elevation after starch loading in vivo, but it had no effect after glucose loading. In contrast to the non-competitive inhibition of wheat α-amylase inhibitor, buckwheat albumin acted in a competitive manner. Although buckwheat α-amylase inhibitor was readily hydrolysed by digestive enzymes, the hydrolysate retained inhibitory activity. Together with its thermal stability, this suggests its potential use in functional foods that prevent diabetes