Evaluation of protein pattern changes in roots and leaves of Zea maysplants in response to nitrate availability by two-dimensional gel electrophoresis analysis

Abstract

BackgroundNitrogen nutrition is one of the major factors that limit growth and production of crop plants. It affects many processes, such as development, architecture, flowering, senescence and photosynthesis. Although the improvement in technologies for protein study and the widening of gene sequences have made possible the study of the plant proteomes, only limited information on proteome changes occurring in response to nitrogen amount are available up to now. In this work, two-dimensional gel electrophoresis (2-DE) has been used to investigate the protein changes induced by NO3- concentration in both roots and leaves of maize (Zea mays L.) plants. Moreover, in order to better evaluate the proteomic results, some biochemical and physiological parameters were measured.ResultsThrough 2-DE analysis, 20 and 18 spots that significantly changed their amount at least two folds in response to nitrate addition to the growth medium of starved maize plants were found in roots and leaves, respectively. Most of these spots were identified by Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS). In roots, many of these changes were referred to enzymes involved in nitrate assimilation and in metabolic pathways implicated in the balance of the energy and redox status of the cell, among which the pentose phosphate pathway. In leaves, most of the characterized proteins were related to regulation of photosynthesis. Moreover, the up-accumulation of lipoxygenase 10 indicated that the leaf response to a high availability of nitrate may also involve a modification in lipid metabolism.Finally, this proteomic approach suggested that the nutritional status of the plant may affect two different post-translational modifications of phosphoenolpyruvate carboxylase (PEPCase) consisting in monoubiquitination and phosphorylation in roots and leaves, respectively.ConclusionThis work provides a first characterization of the proteome changes that occur in response to nitrate availability in leaves and roots of maize plants. According to previous studies, the work confirms the relationship between nitrogen and carbon metabolisms and it rises some intriguing questions, concerning the possible role of NO and lipoxygenase 10 in roots and leaves, respectively. Although further studies will be necessary, this proteomic analysis underlines the central role of post-translational events in modulating pivotal enzymes, such as PEPCase.

Assembly and Sorting of the Tonoplast Potassium Channel AtTPK1 and Its Turnover by Internalization into the Vacuole

“…Upon Coomassie Blue staining, a major band corresponding to the larger AtTPK1-GFP isoform was identified and excised. After trypsin digestion (Prinsi et al, 2009), the sample was analyzed on an Agilent 6520 Q-TOF mass spectrometer with an HPLC Chip Cube source (Agilent Technologies). Analysis of tandem mass spectrometry spectra for peptides identification was performed by database searching with Spectrum Mill software (Agilent Technologies).…”

Reciprocal Control of Anaplerotic Phosphoenolpyruvate Carboxylase by in Vivo Monoubiquitination and Phosphorylation in Developing Proteoid Roots of Phosphate-Deficient Harsh Hakea

“…Arabidopsis seedlings and most tissues of the castor plant (Uhrig et al, 2008;O'Leary et al, 2011b), maize (Zea mays) roots and leaves (Prinsi et al, 2009), and lily (Lilium spp.) pollen (Igawa et al, 2010).…”

Proteins involved in biotic and abiotic stress responses as the most significant biomarkers in the ripening of Pinot Noir skins

“…Spots excised from cCBB-stained 2-DE gels were digested as previously described by Prinsi et al (2009) and the resulted tryptic peptides were resuspended in 0.1% (v/v) formic acid (FA).…”