Effects of different nitrogen fertilizers on two wheat cultivars: An integrated approach

Investigation of cultivated plant physiology grown under low energy input plays an important role to indicate their fitness to the new environmental conditions. The durum‐wheat cultivars Creso and Dylan were tested to evaluate the growth, production, and proteomic and transcriptomic profiles of the crop under different synthetic and organic nitrogen fertilization regimes. In this work, a two‐dimensional gel electrophoresis (2‐DE) approach combined with liquid chromatography–mass spectrometry (LC–MS) was used to investigate the protein changes induced by the use of different nitrogen sources (hydrolysate of proteins 1 and 2, rhizovit, synthesis, leather) on wheat plants. Proteomic studies were integrated with qPCR analysis of genes related to glutamine synthetase/glutamine‐2‐oxoglutarate aminotransferase (GS‐GOGAT) and tricarboxylic acid (TCA) metabolic pathways because most relevant for nitrogen‐dependent plants growth. The proteomic analysis lead to the isolation of 23 spots that were able to distinguish the analyzed samples. These spots yielded the identification of 60 proteins involved in photosynthesis, glycolysis, and nitrogen metabolism. As an example, the quinone oxidoreductase‐like protein and probable glutathione S‐transferase GSTU proteins were identified in two spots that represents the most statistically significant ones in Dylan samples. Transcript analysis indicated that related genes exhibited different expression trends; the heat map also revealed the different behaviors of the hydrolysates of the proteins 1 and 2 nitrogen sources. The effects of nitrogenous fertilizers at the proteomic and agronomic levels revealed that plants fertilized with synthesis or rhizovit gave the best results concerning yield, whereas rhizovit and protein hydrolysates were most effective for proteins content in the grain (% of dry weight). Therefore, all parameters measured in this study indicated that different kinds of nitrogen fertilization used have a relevant impact on plant growth and production

A pathway-specific microarray analysis highlights the complex and co-ordinated transcriptional networks of the developing grain of field-grown barley

The aim of the study was to describe the molecular and biochemical interactions associated with amino acid biosynthesis and storage protein accumulation in the developing grains of field-grown barley. Our strategy was to analyse the transcription of genes associated with the biosynthesis of storage products during the development of field-grown barley grains using a grain-specific microarray assembled in our laboratory. To identify co-regulated genes, a distance matrix was constructed which enabled the identification of three clusters corresponding to early, middle, and late grain development. The gene expression pattern associated with the clusters was investigated using pathway-specific analysis with specific reference to the temporal expression levels of a range of genes involved mainly in the photosynthesis process, amino acid and storage protein metabolism. It is concluded that the grain-specific microarray is a reliable and cost-effective tool for monitoring temporal changes in the transcriptome of the major metabolic pathways in the barley grain. Moreover, it was sensitive enough to monitor differences in the gene expression profiles of different homologues from the storage protein families. The study described here should provide a strong complement to existing knowledge assisting further understanding of grain development and thereby provide a foundation for plant breeding towards storage proteins with improved nutritional quality

Reference genes for gene expression studies in wheat flag leaves grown under different farming conditions

<p>Abstract</p> <p>Background</p> <p>Internal control genes with highly uniform expression throughout the experimental conditions are required for accurate gene expression analysis as no universal reference genes exists. In this study, the expression stability of 24 candidate genes from <it>Triticum aestivum </it>cv. Cubus flag leaves grown under organic and conventional farming systems was evaluated in two locations in order to select suitable genes that can be used for normalization of real-time quantitative reverse-transcription PCR (RT-qPCR) reactions. The genes were selected among the most common used reference genes as well as genes encoding proteins involved in several metabolic pathways.</p> <p>Findings</p> <p>Individual genes displayed different expression rates across all samples assayed. Applying geNorm, a set of three potential reference genes were suitable for normalization of RT-qPCR reactions in winter wheat flag leaves cv. Cubus: <it>TaFNRII </it>(ferredoxin-NADP(H) oxidoreductase; AJ457980.1), <it>ACT2 </it>(actin 2; TC234027), and <it>rrn26 </it>(a putative homologue to RNA 26S gene; AL827977.1). In addition of these three genes that were also top-ranked by NormFinder, two extra genes: <it>CYP18-2 </it>(Cyclophilin A, AY456122.1) and <it>TaWIN1 </it>(14-3-3 like protein, AB042193) were most consistently stably expressed.</p> <p>Furthermore, we showed that <it>TaFNRII, ACT2</it>, and <it>CYP18-2 </it>are suitable for gene expression normalization in other two winter wheat varieties (Tommi and Centenaire) grown under three treatments (organic, conventional and no nitrogen) and a different environment than the one tested with cv. Cubus.</p> <p>Conclusions</p> <p>This study provides a new set of reference genes which should improve the accuracy of gene expression analyses when using wheat flag leaves as those related to the improvement of nitrogen use efficiency for cereal production.</p

Breeding for increased nitrogen-use efficiency: a review for wheat (T. aestivum L.)

Nitrogen fertilizer is the most used nutrient source in modern agriculture and represents significant environmental and production costs. In the meantime, the demand for grain increases and production per area has to increase as new cultivated areas are scarce. In this context, breeding for an efficient use of nitrogen became a major objective. In wheat, nitrogen is required to maintain a photosynthetically active canopy ensuring grain yield and to produce grain storage proteins that are generally needed to maintain a high end-use quality. This review presents current knowledge of physiological, metabolic and genetic factors influencing nitrogen uptake and utilization in the context of different nitrogen management systems. This includes the role of root system and its interactions with microorganisms, nitrate assimilation and its relationship with photosynthesis as postanthesis remobilization and nitrogen partitioning. Regarding nitrogen-use efficiency complexity, several physiological avenues for increasing it were discussed and their phenotyping methods were reviewed. Phenotypic and molecular breeding strategies were also reviewed and discussed regarding nitrogen regimes and genetic diversity

Nitrogen partitioning and remobilization in relation to leaf senescence, grain yield and grain nitrogen concentration in wheat cultivars

Our objective was to investigate the determinants of genetic variation in N accumulation, N partitioning and N remobilization to the grain post-flowering and associations with flag-leaf senescence, grain yield and grain N% in 16 wheat cultivars grown under high N (HN) and low N (LN) conditions in the UK and France. Overall, cultivars ranged in leaf lamina N accumulation at anthesis from 5.32 to 8.03 g N m−2 at HN and from 2.69 to 3.62 g N m−2 at LN, and for the stem-and leaf-sheath from 5.45 to 7.25 g N m−2 at HN and from 2.55 to 3.41 g N m−2 at LN (P < 0.001). Cultivars ranged in N partitioning index (proportion of above-ground N in the crop component) at anthesis for the leaf lamina from 0.37 to 0.42 at HN and 0.34 to 0.40 at LN; and for the stem-and leaf-sheath from 0.39 to 0.43 at HN and from 0.35 to 0.41 at LN (P < 0.001). The amount of leaf lamina N remobilized post-anthesis was negatively associated with the duration of post-anthesis flag-leaf senescence amongst cultivars in all experiments under HN. In general, it was difficult to separate genetic differences in lamina N remobilization from those in lamina N accumulation at anthesis. Genetic variation in grain yield and grain N% (through N dilution effects) appeared to be mainly influenced by pre-anthesis N accumulation rather than post-anthesis N remobilization under high N conditions and under milder N stress (Sutton Bonington LN). Where N stress was increased (Clermont Ferrand LN), there was some evidence that lamina N remobilization was a determinant of genetic variation in grain N% although not of grain yield. Our results suggested that selection for lamina N accumulation at anthesis and lamina N remobilization post-anthesis may have value in breeding programmes aimed at optimizing senescence duration and improving grain yield, N-use efficiency and grain N% of wheat

Etude agronomique, physiologique et cytologique de la remobilisation de l'azote au cours de la phase de remplissage du grain chez le blé tendre d'hiver (Triticum aestivum L.)

AMIENS-BU Sciences (800212103) / SudocSudocFranceF

Foliar nitrogen application in wheat: the effects on grain N content, recovery of fertilizer and the response of cytosolic glutamine synthetase

Foliar application of N fertilizer is an efficient strategy with respect to boosting grain protein content and matching plant N demand with the actual climatic conditions in the growing season. However, foliar N application implies the risk of leaf damage. We would like to develop wheat genotypes that are better suited for foliar N fertilization. Therefore, wheat plants were subjected to different fertilization regimes including foliar application of N to investigate the effect on plant growth and molecular-physiological parameters related to nitrogen use efficiency. Using 15N as a tracer, we have observed that an unexpected large proportion (about 50%) of the N applied to the leaves remained in the vegetative plant parts at maturity, suggesting a bottleneck in the translocation of N to the grain. As cytosolic glutamine synthetase is a central enzyme in the assimilation and translocation of N from the leaves to the grain, we analysed GS activity and protein levels. GS activity in flag leaf increased in response to foliar application of N although the levels of GS protein were similar for the different treatments and growth stages during grain filling. Currently, GS gene expression is under investigation using Q-PCR