Sensor-based phenotyping of above-ground plant-pathogen interactions.

Plant pathogens cause yield losses in crops worldwide. Breeding for improved disease resistance and management by precision agriculture are two approaches to limit such yield losses. Both rely on detecting and quantifying signs and symptoms of plant disease.

Proton-pumping pyrophosphatase homeolog expression is a dynamic trait in bread wheat ().

Proton-pumping pyrophosphatases (H-PPases) have been shown to enhance biomass and yield. However, to date, there has been little work towards identify genes encoding H-PPases in bread wheat () (s) and limited knowledge on how the expression of these genes varies across different growth stages and tissue types. In this study, the IWGSC database was used to identify two novel genes, and , and elucidate the complete homeolog sequences of the three known genes, bringing the total number of bread wheat s from 9 to 15.

The phosphoproteome of rice leaves responds to water and nitrogen supply.

The scarcity of freshwater is an increasing concern in flood-irrigated rice, whilst excessive use of nitrogen fertilizers is costly and contributes to environmental pollution. To co-ordinate growth adaptation under prolonged exposure to limited water or excess nitrogen supply, plants employ complex systems for signalling and regulation of metabolic processes. There is limited information on the involvement of one of the most important post-translational modifications (PTMs), protein phosphorylation, in plant adaptation to long-term changes in resource supply.

Continuous monitoring of plant sodium transport dynamics using clinical PET.

Background: The absorption, translocation, accumulation and excretion of substances are fundamental processes in all organisms including plants, and have been successfully studied using radiotracers labelled with C, N, C and Na since 1939. Sodium is one of the most damaging ions to the growth and productivity of crops. Due to the significance of understanding sodium transport in plants, a significant number of studies have been carried out to examine sodium influx, compartmentation, and efflux using Na- or Na-labeled salts.

Improved Yield and Photosynthate Partitioning in AVP1 Expressing Wheat () Plants.

A fundamental factor to improve crop productivity involves the optimization of reduced carbon translocation from source to sink tissues. Here, we present data consistent with the positive effect that the expression of the H-PPase () has on reduced carbon partitioning and yield increases in wheat. Immunohistochemical localization of H-PPases (TaVP) in spring wheat Bobwhite L.

The intersection of nitrogen nutrition and water use in plants: new paths toward improved crop productivity.

Water and nitrogen availability limit crop productivity globally more than most other environmental factors. Plant availability of macronutrients such as nitrate is, to a large extent, regulated by the amount of water available in the soil, and, during drought episodes, crops can become simultaneously water and nitrogen limited. In this review, we explore the intricate relationship between water and nitrogen transport in plants, from transpiration-driven mass flow in the soil to uptake by roots via membrane transporters and channels and transport to aerial organs.

Energy costs of salt tolerance in crop plants.

Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed.

Plasma-membrane electrical responses to salt and osmotic gradients contradict radiotracer kinetics, and reveal Na-transport dynamics in rice (Oryza sativa L.).

A systematic analysis of NaCl-dependent, plasma-membrane depolarization (∆∆Ψ) in rice roots calls into question the current leading model of rapid membrane cycling of Na under salt stress. To investigate the character and mechanisms of Na influx into roots, Na-dependent changes in plasma-membrane electrical potentials (∆∆Ψ) were measured in root cells of intact rice (Oryza sativa L., cv.

Integrated genomics, physiology and breeding approaches for improving nitrogen use efficiency in potato: translating knowledge from other crops.

Potato plays a key role in global food and nutritional security. Potato is an N fertiliser-responsive crop, producing high tuber yields. However, excessive use of N can result in environmental damage and high production costs, hence improving nitrogen use efficiency (NUE) of potato plants is one of the sustainable options to address these issues and increase yield.

Structural variations in wheat HKT1;5 underpin differences in Na transport capacity.

An important trait associated with the salt tolerance of wheat is the exclusion of sodium ions (Na) from the shoot. We have previously shown that the sodium transporters TmHKT1;5-A and TaHKT1;5-D, from Triticum monoccocum (Tm) and Triticum aestivum (Ta), are encoded by genes underlying the major shoot Na-exclusion loci Nax1 and Kna1, respectively. Here, using heterologous expression, we show that the affinity (K ) for the Na transport of TmHKT1;5-A, at 2.

Nitrate uptake and its regulation in relation to improving nitrogen use efficiency in cereals.

On average less than half of the applied N is captured by crops, thus there is scope and need to improve N uptake in cereals. With nitrate (NO) being the main form of N available to cereal crops there has been a significant global research effort to understand plant NO uptake. Despite this, our knowledge of the NO uptake system is not sufficient to easily target ways to improve NO uptake.

Transition from a maternal to external nitrogen source in maize seedlings.

Maximizing NO uptake during seedling development is important as it has a major influence on plant growth and yield. However, little is known about the processes leading to, and involved in, the initiation of root NO uptake capacity in developing seedlings. This study examines the physiological processes involved in root NO uptake and metabolism, to gain an understanding of how the NO uptake system responds to meet demand as maize seedlings transition from seed N use to external N capture.

AVP1: One Protein, Many Roles.

Constitutive expression of the Arabidopsis vacuolar proton-pumping pyrophosphatase (H-PPase) gene (AVP1) increases plant growth under various abiotic stress conditions and, importantly, under nonstressed conditions. Many interpretations have been proposed to explain these phenotypes, including greater vacuolar ion sequestration, increased auxin transport, enhanced heterotrophic growth, and increased transport of sucrose from source to sink tissues. In this review, we evaluate all the roles proposed for AVP1, using findings published to date from mutant plants lacking functional AVP1 and transgenic plants expressing AVP1.

Nitrogen assimilation system in maize is regulated by developmental and tissue-specific mechanisms.

We found metabolites, enzyme activities and enzyme transcript abundances vary significantly across the maize lifecycle, but weak correlation exists between the three groups. We identified putative genes regulating nitrate assimilation. Progress in improving nitrogen (N) use efficiency (NUE) of crop plants has been hampered by the complexity of the N uptake and utilisation systems.

Variation for N Uptake System in Maize: Genotypic Response to N Supply.

An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply.

Genetic approaches to enhancing nitrogen-use efficiency (NUE) in cereals: challenges and future directions.

Over 100million tonnes of nitrogen (N) fertiliser are applied globally each year to maintain high yields in agricultural crops. The rising price of N fertilisers has made them a major cost for farmers. Inefficient use of N fertiliser leads to substantial environmental problems through contamination of air and water resources and can be a significant economic cost.

Maize maintains growth in response to decreased nitrate supply through a highly dynamic and developmental stage-specific transcriptional response.

Elucidation of the gene networks underlying the response to N supply and demand will facilitate the improvement of the N uptake efficiency of plants. We undertook a transcriptomic analysis of maize to identify genes responding to both a non-growth-limiting decrease in NO3- provision and to development-based N demand changes at seven representative points across the life cycle. Gene co-expression networks were derived by cluster analysis of the transcript profiles.

The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL.

Expression of the Arabidopsis vacuolar H⁺-pyrophosphatase gene (AVP1) improves the shoot biomass of transgenic barley and increases grain yield in a saline field.

Cereal varieties with improved salinity tolerance are needed to achieve profitable grain yields in saline soils. The expression of AVP1, an Arabidopsis gene encoding a vacuolar proton pumping pyrophosphatase (H⁺-PPase), has been shown to improve the salinity tolerance of transgenic plants in greenhouse conditions. However, the potential for this gene to improve the grain yield of cereal crops in a saline field has yet to be evaluated.

The response of the maize nitrate transport system to nitrogen demand and supply across the lifecycle.

An understanding of nitrate (NO3-) uptake throughout the lifecycle of plants, and how this process responds to nitrogen (N) availability, is an important step towards the development of plants with improved nitrogen use efficiency (NUE). NO3- uptake capacity and transcript levels of putative high- and low-affinity NO3- transporters (NRTs) were profiled across the lifecycle of dwarf maize (Zea mays) plants grown at reduced and adequate NO3-. Plants showed major changes in high-affinity NO3- uptake capacity across the lifecycle, which varied with changing relative growth rates of roots and shoots.

A two-staged model of Na+ exclusion in rice explained by 3D modeling of HKT transporters and alternative splicing.

The HKT family of Na(+) and Na(+)/K(+) transporters is implicated in plant salinity tolerance. Amongst these transporters, the cereal HKT1;4 and HKT1;5 are responsible for Na(+) exclusion from photosynthetic tissues, a key mechanism for plant salinity tolerance. It has been suggested that Na(+) is retrieved from the xylem transpiration stream either in the root or the leaf sheath, protecting the leaf blades from excessive Na(+) accumulation.

Wheat grain yield on saline soils is improved by an ancestral Na⁺ transporter gene.

The ability of wheat to maintain a low sodium concentration ([Na(+)]) in leaves correlates with improved growth under saline conditions. This trait, termed Na(+) exclusion, contributes to the greater salt tolerance of bread wheat relative to durum wheat. To improve the salt tolerance of durum wheat, we explored natural diversity in shoot Na(+) exclusion within ancestral wheat germplasm.

Dichotomy in the NRT gene families of dicots and grass species.

A large proportion of the nitrate (NO(3)(-)) acquired by plants from soil is actively transported via members of the NRT families of NO(3)(-) transporters. In Arabidopsis, the NRT1 family has eight functionally characterised members and predominantly comprises low-affinity transporters; the NRT2 family contains seven members which appear to be high-affinity transporters; and there are two NRT3 (NAR2) family members which are known to participate in high-affinity transport. A modified reciprocal best hit (RBH) approach was used to identify putative orthologues of the Arabidopsis NRT genes in the four fully sequenced grass genomes (maize, rice, sorghum, Brachypodium).