Why has nitrogen fertilizer use declined in some countries while increasing others, despite significant environmental harm? Proper crop management strategies offer and economic benefits without sacrificing yields.

Summary Nitrogen is quantitatively the most essential nutrient for plants and a major factor limiting crop productivity. One of critical steps efficient use nitrogen ability to acquire it from applied fertilizer. Therefore, development that absorb more efficiently has been long-term goal agricultural research. In an attempt develop nitrogen-efficient plants, rice (Oryza sativa L.) was genetically engineered by introducing barley AlaAT (alanine aminotransferase) cDNA driven tissue-specific...

Plants, like animals, are obligate aerobes, but due to their inability move, have evolved adaptation mechanisms that enable them survive short periods of low oxygen supply, such as those occurring after heavy rain or flooding. Crop plants often grown on soils subject waterlogging and many sensitive the root zone. The combination unfavourable weather conditions suboptimal soil irrigation techniques can result in severe yield losses. molecular basis transient has not been completely...

A field in which Brassica napus volunteers were not controlled by several applications of glyphosate was investigated 1998. This had been planted with glufosinate-resistant and imidazolinone-resistant B. 1997 adjacent to a that grown glyphosate-resistant napus. Mature volunteer collected on 50- 100-m grid the field. Progeny from 34 sprayed at 440 g ae ha−1, survivors either glufosinate or imazethapyr 400 50 ai respectively. Where seed numbers permitted (14 volunteers), seedlings also...

Abstract We manipulated the enzyme activity levels of alcohol fermentation pathway, pyruvate decarboxylase (PDC), and dehydrogenase (ADH) in Arabidopsis using sense antisense overexpression corresponding genes (PDC1, PDC2, ADH1). Transgenic plants were analyzed for evaluated changes hypoxic survival. Overexpression either PDC1 or PDC2 resulted improved plant In contrast, ADH1 had no effect on flooding These results support role PDC as control step ethanol fermentation. Although null mutants...

Summary Alanine aminotransferase (AlaAT) catalyses the reversible transfer of an amino group from glutamate to pyruvate form 2‐oxoglutarate and alanine. The regulation AlaAT in several plant species has been studied response low‐oxygen stress, light nitrogen application. In this study, induction Arabidopsis AlaAT1 AlaAT2 during hypoxia was observed at transcriptional level, increase enzyme activity detected hypoxically treated roots. addition, tissue‐specific expression analysed using...

Changes in the concentrations of free amino acids and specific organic were analysed during induction drought stress Brassica napus . Most showed a characteristic linear increase with leaves, increasing an average 5.9‐fold over control levels, followed by reduction concentration upon rehydration plants. Pyruvate doubled after 4 days whereas 2‐oxoglutarate remained relatively constant. The activities two enzymes involved acid biosynthesis, alanine aminotransferase (EC 2.6.1.2) aspartate...

Nitrogen (N) is the most important factor limiting crop productivity worldwide. The ability of plants to acquire N from applied fertilizers one critical steps efficient use nitrogen. To improve efficiency, genetically modified that overexpress alanine aminotransferase (AlaAT) were engineered by introducing a barley AlaAT cDNA driven canola root specific promoter (btg26). Compared with wild-type canola, transgenic had increased biomass and seed yield both in laboratory field under low...

Temperatures higher than the optimum negatively affects plant growth and development. Tolerance to high temperature is a complex process that involves several pathways. Understanding this process, especially in crops such as rice, essential prepare for predicted climate changes due global warming. Here, we show OsMYB55 induced by overexpression of resulted improved under decreased negative effect on grain yield. Transcriptome analysis revealed an increase expression genes involved amino...

Abstract We investigated the role that manganese superoxide dismutase (MnSOD, EC 1·15·1·1), an important enzyme of antioxidant pathway, may play in aluminium (Al) toxicity/resistance. A wheat ( Triticum aestivum ) cDNA WMnSOD was cloned and up‐regulation transcript observed root tips after 24 h exposure to 100 µ m Al. The WMnSOD1 under control CaMV 35S promoter expressed canola Brassica napus ). Transgenic plants were phenotypically normal. Northern analyses showed enhanced levels...

When subjected to low oxygen stress, plants accumulate alanine and gamma-aminobutyric acid (GABA). To investigate the function of GABA metabolism under hypoxia its contribution accumulation, we studied genes that encode two key enzymes shunt, glutamate decarboxylase (GAD) transaminase (GABA-T). Among five homologous GAD found in Arabidopsis thaliana, GAD1 expression was predominantly roots, while GAD2 evident all organs. Expression other three generally weak. In response hypoxia,...

What are the next steps in engineering crop plants that fix nitrogen and make their own fertilizer?

The interaction between phytohormones is an important mechanism which controls growth and developmental processes in plants. Deciphering these interactions a crucial step helping to develop crops with enhanced yield resistance environmental stresses. Controlling the expression level of OsAP2-39 includes APETALA 2 (AP2) domain leads phenotypic changes rice. Overexpression reduction by decreasing biomass number seeds transgenic rice lines. Global transcriptome analysis overexpression revealed...

Interconversion between glutamate and 2-oxoglutarate, which can be catalysed by dehydrogenase (GDH), is a key reaction in plant carbon (C) nitrogen (N) metabolism. However, the physiological role of GDH has been controversial issue for several decades. To elucidate function GDH, expression various tissues Arabidopsis thaliana was studied. Results suggested that two genes differently regulated depending on organ/tissue types cellular C availability. Moreover, mutants defective were identified...

A concerted research effort could yield engineered plants that can directly fix nitrogen

The onset of anaerobiosis in barley root tissue (Hordeum vulgare L. cv Himalaya) results the following metabolic responses. There are rapid increases levels pyruvate, lactate, and ethanol. Malate succinate concentrations increase over first 12 h, after which they return to found oxygenated tissue. Alanine concentration this is matched by a corresponding decrease aspartate. initial stoichiometric decline aspartate alanine suggests that amino group conserved transaminating pyruvate alanine....

Microtubules play an essential role in the growth and development of plants are known to be involved regulating many cellular processes ranging from translation signaling. In this article, we describe proteomic characterization Arabidopsis tubulin-binding proteins that were purified using tubulin affinity chromatography. Microtubule co-sedimentation assays indicated most, if not all, protein fraction possessed microtubule-binding activity. Two-dimensional gel electrophoresis was performed,...

Alanine aminotransferase, otherwise called glutamate-pyruvate aminotransferase (GPT), activity increases up to fourfold during several days of anaerobic induction in barley (Hordeum vulgare L.) roots, reaching a maximum 13 international units per gram fresh weight. This increase paralleled the alcohol dehydrogenase same root tissue. Upon return aerobic conditions, induced GPT declined with an apparent half-life 2 days. The isozyme profile tissue comprised one band activity; maize there were...

Increasing costs of N fertilizers and the negative impact excessive on environment have made improvement in nitrogen use efficiency (NUE) a desirable goal barley ( Hordeum vulgare L.) breeding. Seventeen replicated trials, each consisting 15 to 20 genotypes, were performed across different environments Alberta, Canada from 1998 2007 determine genetic variability NUE. Further, 25 genotypes grown at six for analysis pattern genotypic variation Analysis variance revealed significant effects...

Gibberellins (GAs) are key modulators of plant growth and development. PsGA3ox1 (LE) encodes a GA 3β-hydroxylase that catalyzes the conversion GA20 to biologically active GA1. To further clarify role GA3ox expression during pea (Pisum sativum) development, we generated transgenic lines (in lele background) with cauliflower mosaic virus-35S-driven (LE). transgene led higher GA1 concentrations in tissue-specific development-specific manner, altering biosynthesis catabolism gene phenotype....

Nitrogen-use efficiency (NUE) of cereals needs to be improved by nitrogen (N) management, traditional plant breeding methods and/or biotechnology, while maintaining or, optimally, increasing crop yields. The aims this study were compare spring-barley genotypes grown on different levels in field and growth-chamber conditions determine the effects N uptake (NUpE) utilization (NUtE) ultimately, NUE.Morphological characteristics, seed yield metabolite 12 spring barley (Hordeum vulgare) compared...