It Was Found That Amino Sugar Nitrogen Was a New Source of Energy for Plant

Abstract

Amino sugar nitrogen (ASN) is one of the most important nitrogen sources for plants. Whether ASN such as glucosamine can be absorbed directly by plants has remained unclear, because the technology for investigating its mechanism of absorption has been lacking. Using Positron Emission Tomography (PET) with 18 F-fluorodeoxyglucose ( 18 F-FDG), we observed that ASN was absorbed directly by tomatoes and rice and this absorption was significantly influenced by the carbon to nitrogen ratio (C/N) and the pH value of the growth substrate solution of tomatoes and rice. Absorption and transportation of ASN was measured at C/N ratios of 10 or 25 at pH 7.0 or 8.0 in tomato and at pH 5.5 or 6.5 in rice. A C/N ratio of 10 resulted in higher ASN absorption and transportation than a C/N ratio of 25 in both tomatoes and rice. At C/N ratio of 10, tomatoes absorbed more ASN at pH 8.0 than at pH 7.0. In rice, absorption was more at pH 5.5 than 6.5. In a word, a lower C/N ratio yielded a higher ASN absorption and transportation for both tomatoes and rice. Tomatoes showed a slight preference for alkaline conditions, whereas rice preferred acidic conditions.

Applications of 2-deoxy-2-fluoro-D-glucose (FDG) in Plant Imaging: Past, Present, and Future

“…This involves wounding (cut/scratch/prick) a mature leaf at the distal end and applying FDG solution to the wounded region (as in Hattori et al, 2008 ; Fatangare et al, 2014 , 2015 ; Meldau et al, 2015 ). The third, “uptake through root,” involves dipping the plant’s root in FDG solution (as in Li et al, 2014 ). Upon uptake, the radioactivity associated with FDG translocates through the plant vasculature in the form of ‘FDG and/or its metabolites, which are cumulatively represented by [ 18 F]-radioactivity.…”

“…In the third method of FDG uptake (uptake through root), plant roots were placed in FDG solution (as in Li et al, 2014 ; Partelová et al, 2014 ). Radiograms showed that very little [ 18 F]-radioactivity was translocated to parts above-ground.…”

“…2-Deoxy-2-fluoro- D -glucose is already being used as a tracer in plant imaging research. It was employed as a tracer for photoassimilate ( Hattori et al, 2008 ), or glycoside biosynthesis, or ( Ferrieri et al, 2012 ), or root-mediated uptake of glucosamine ( Li et al, 2014 ), or the visualization and quantification of solute transport in plant tissue ( Partelová et al, 2014 ), or studying carbon allocation ( Meldau et al, 2015 ). This great diversity of FDG applications arises from the different methods of FDG uptake and the purpose experimenters have in mind.…”

“…FDG has been used to study glycoside biosynthesis in plants as a measure of plant response to defense induction ( Ferrieri et al, 2012 ). Recently, FDG has been utilized as a tracer for the root-mediated uptake of glucosamine (glucosamine is a major component of amino sugar nitrogen (ASN) base in the soil) ( Li et al, 2014 ). FDG has been used to visualize and quantify the transport of solutes in plant tissue using PET imaging ( Partelová et al, 2014 ).…”

2-Deoxy-2-fluoro-d-glucose metabolism in Arabidopsis thaliana

“…Recently, 18 FDG has been employed as a radiotracer in plants to study amino-sugar-nitrogen (ASN esp. glucosamine) uptake (Li et al, 2014 ) or solute transport (Partelová et al, 2014 ). We have previously shown that the radioactivity distribution pattern observed after 18 FDG feeding is significantly different than another radiotracer like 68 Gallium-citrate ( 68 Ga-citrate) (Fatangare et al, 2014 ).…”