John P Hammond

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Verified

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• PhD
• Professor at University of Reading

Hunger remains a prevalent issue worldwide, and with a changing climate, it is expected to become an even greater problem that our food systems are not adapted to. There is therefore a need to investigate strategies to fortify our foods and food systems. Underutilized crops are farmed regionally, are often adapted to stresses, including droughts, a...

Phosphorus (P) is an essential macronutrient for the growth and yield of crops. However, there is limited understanding of the regulatory mechanisms of phosphate (Pi) homeostasis, and its impact on growth, development, and yield-related traits in Brassica napus. Here, we identified four NITROGEN LIMITATION ADAPTATION1 (BnaNLA1) genes in B. napus; t...

Key message BnaPAP17s associated with root-secreted APases activity were identified by genome-wide association study, and those were induced by Pi-deficiency. BnaPAP17s were involved in improving exogenous organophosphorus utilization as secreted APases. Abstract Deficiency of available phosphorus (P) in soil has become an important limiting facto...

To maximise the throughput of novel, high-throughput phenotyping platforms, many researchers have utilised smaller pot sizes to increase the number of biological replicates that can be grown in spatially limited controlled environments. This may confound plant development through a process known as “pot binding”, particularly in larger species incl...

Main conclusion Overexpression of BnaC02.TPS8 increased low N and high sucrose-induced anthocyanin accumulation. Abstract Anthocyanin plays a crucial role in safeguarding photosynthetic tissues against high light, UV radiation, and oxidative stress. Their accumulation is triggered by low nitrogen (N) stress and elevated sucrose levels in Arabidops...

Farmer adoption of so-called Precision Agriculture (PA) or ‘smart’ technologies in the arable sector has grown in the last few decades with a focus on Global Navigation Satellite Systems (GNSS) and variable rate technologies (VRT). This has led to increased generation of large volumes of data about fields and their crop yields which could be used t...

Oilseed rape (Brassica napus), one of the most important sources of vegetable oil worldwide, is adversely impacted by heat wave-induced temperature stress especially during its yield determining reproductive stages. However, the underlying molecular and biochemical mechanisms are still poorly understood. In this study, we investigated the physiolog...

Vacuolar Pi transporters (VPTs) have recently been identified as important regulators of cellular Pi status in Arabidopsis thaliana and Oryza sativa. In the oil crop Brassica napus, BnA09PHT5;1a and BnC09PHT5;1a are two homologs of AtPHT5;1, the vacuolar Pi influx transporter in Arabidopsis. Here, we show that Pi deficiency induces the transcriptio...

Oilseed rape ( Brassica napus ) is one of the most important oil crops in the world and shows sensitivity to low phosphorus (P) availability. In many soils, organic P (Po) is the main component of the soil P pool. Po must be mineralised to Pi through phosphatases, and then taken up by plants. However, the relationship between root‐secreted acid pho...

Trehalose‐6‐phosphate (T6P) functions as a vital proxy for assessing carbohydrate status in plants. While class II T6P synthases (TPS) do not exhibit TPS activity, they are believed to play pivotal regulatory roles in trehalose metabolism. However, their precise functions in carbon metabolism and crop yield have remained largely unknown. Here, BnaC...

Aims The aims of this work were to investigate phosphate starvation responses of Brassica napus (B. napus) under heterogeneous phosphate (Pi) supply and the regulatory role of jasmonic acid (JA) in the systemic response to Pi starvation. Methods A split-root system with two separated compartments was employed to mimic heterogeneous Pi distribution...

Unlabelled: Optimal root system architecture (RSA) is essential for vigorous growth and yield in crops. Plants have evolved adaptive mechanisms in response to low phosphorus (LP) stress, and one of those is changes in RSA. Here, more than five million single-nucleotide polymorphisms (SNPs) obtained from whole-genome re-sequencing data (WGR) of an...

Unlabelled: Oilseed rape (Brassica napus L.; B. napus) is an important oil crop worldwide. However, the genetic mechanisms of B. napus adaptations to low phosphate (P) stress are largely unknown. In this study, a genome-wide association study (GWAS) identified 68 SNPs significantly associated with seed yield (SY) under low P (LP) availability, and...

Soil compaction due to mechanized farming operations is a recurrent issue affecting crop growth and yield. Yet, how soil compaction affects plant functions and ecological strategies is poorly known. With Brassica napus, i.e. a widespread crop species as study object, we aim to understand (i) how soil compaction impacts root and shoot traits related...

Abstracts: Wheat yield is highly dependent on weather, Therefore, predicting its effect can improve crop management decisions. Various modelling approaches have been used to predict wheat yield including process-based modelling, statistical models, and machine learning. However, these models typically require a large data set for training or fittin...

Phosphorus (P) is an indispensable macronutrient serving a variety of functions in plants. Inositol pyrophosphates (PP-InsPs) nutrient messengers play vital roles in the signaling of P status and plant growth and development. In this review, we summarize (1) the biosynthetic pathway of PP-InsPs and their regulation by plant P status, (2) the effect...

Natural flood management (NFM) involves measures to restore and protect natural hydrology and geo-morphology to minimise flood risk. NFM is promoted as part of the nation's flood resilience response. Government agencies have created national maps of opportunities for specific NFM measure to target available grant aid and encourage landowners and ma...

Oilseed rape ( Brassica napus L.; B. napus ) is an important oil crop around the world. However, the genetic mechanism of B. napus adaptations to low phosphate (P) stress are largely unknown. In this study, a genome-wide association study (GWAS) identified 68 SNPs significantly associated with seed yield (SY) under low P (LP) availability in two tr...

Diet is a key modulator of non‐communicable diseases, and food production represents a major cause of environmental degradation and greenhouse gas emissions. Yet, ‘nudging’ people to make better food choices is challenging, as factors including affordability, convenience and taste often take priority over the achievement of health and environmental...

Oilseed rape (Brassica napus L.) is the most important temperate oil crop globally. Maintenance of soil phosphate (Pi) availability, through the application of Pi fertilizers and manures, is needed to maintain seed yield of oilseed rape. Over-application of the Pi fertilizers results in Pi accumulation in agricultural soils and adjacent ecosystems...

Phosphorus (P) is an important nutrient for plants. Here, we identify a WRKY transcription factor (TF) in poplar (PdeWRKY65) that modulates tissue phosphate (Pi) concentration in poplar. Over expression (OE) PdeWRKY65 transgenic lines showed reduced shoot Pi concentrations under both low and normal Pi availabilities, while reduced expression (RE) P...

Advances in DNA sequencing technologies have drastically changed our perception of the structure and complexity of the plant microbiome. By comparison, our ability to accurately identify the metabolically active fraction of soil microbiota and its specific functional role in augmenting plant health is relatively limited. Important ecological intera...

Due to the non-uniform distribution of inorganic phosphate (Pi) in the soil, plants modify their root architecture to improve acquisition of this nutrient. In this study, a split-root system was employed to assess the nature of local and systemic signals that modulate root architecture of Brassica napus grown with non-uniform Pi availability. Later...

Oilseed rape (Brassica napus L.; B. napus) is one of the main oil crops in China as well as in the world. Genome‐wide association studies (GWAS) have revolutionised the field of complex agronomic traits. In B. napus, these include seed yield and yield‐related traits, seed oil content, and abiotic and biotic stress‐tolerance traits over the past dec...

Biochars have been proposed as a novel biotechnology to increase crop yields in acidic soils due to a liming effect. However, the application of biochar to soils with a neutral soil pH is less likely to improve yield. A rise in pH typically increases the availability of macronutrients (e.g., PO43-, NO3-) but biochar is known to immobilize some elem...

Given the current rise in global temperatures, heat stress has become a major abiotic challenge affecting the growth and development of various crops and reducing their productivity. Brassica napus, the second largest source of vegetable oil worldwide, experiences a drastic reduction in seed yield and quality in response to heat. This review outlin...

Bacteria possess various regulatory mechanisms to detect and coordinate a response to elemental nutrient limitation. In pseudomonads, the two-component system regulators CbrAB, NtrBC and PhoBR, are responsible for regulating cellular response to carbon (C), nitrogen (N) and phosphorus (P) respectively. Phosphonates are reduced organophosphorus comp...

Background and Aims Oilseed rape (Brassica napus) is one of the most important oil crops worldwide. Phosphorus (P) deficiency severely decreases the plant height (PH) and branch number (BN) of B. napus. However, the genetic bases controlling PH and BN in B. napus under P deficiency remain largely unknown. This study aims to mine candidate genes for...

The advance of DNA sequencing technologies has drastically changed our perception of the complexity and structure of the plant microbiome and its role in augmenting plant health. By comparison, our ability to accurately identify the metabolically active fraction of soil microbiota and their specific functional role is relatively limited. Here, we c...

Plant root angle determines the vertical and horizontal distribution of roots in the soil layer, which further influences the acquisition of phosphorus (P) in topsoil. Large genetic variability for the lateral root angle (root angle) was observed in a linkage mapping population (BnaTNDH population) and an association panel of Brassica napus whether...

The planktonic synthesis of reduced organophosphorus molecules, such as alkylphosphonates and aminophosphonates, represents one half of a vast global oceanic phosphorus redox cycle. Whilst alkylphosphonates tend to accumulate in recalcitrant dissolved organic matter, aminophosphonates do not. Here, we identify three bacterial 2-aminoethylphosphonat...

Magnesium (Mg) and calcium (Ca) are essential mineral nutrients poorly supplied in many human food systems. In grazing livestock, Mg and Ca deficiencies are costly welfare issues. Here, we report a Brassica rapa loss-of-function schengen3 (sgn3) mutant, braA.sgn3.a-1, which accumulates twice as much Mg and a third more Ca in its leaves. We mapped b...

Phosphorus (P) is one of six essential macronutrients in plants to ensure crop growth and productivity. Plants only acquire phosphorus in the form of inorganic phosphate (Pi) known as orthophosphate, mainly in the form of H 2 PO 4 ⁻ . The high demand of Pi in fertilisers for agriculture use contributed to environmental pollution. Therefore, it is i...

[This corrects the article DOI: 10.3389/fpls.2020.597554.].

The cultivated potato (Solanum tuberosum L.) is currently the third most important food crop in the world and is becoming increasingly important to the local economies of developing countries. Climate change threatens to drastically reduce potato yields in areas of the world where the growing season is predicted to become hotter and drier. Modern p...

Bacteroidetes are abundant pathogen-suppressing members of the plant microbiome that contribute prominently to rhizosphere phosphorus mobilisation, a frequent growth-limiting nutrient in this niche. However, the genetic traits underpinning their success in this niche remain largely unknown, particularly regarding their phosphorus acquisition strate...

The planktonic synthesis of reduced organophosphorus molecules, such as alkylphosphonates and aminophosphonates, represents one half of a vast global oceanic phosphorus redox cycle. Whilst alkylphosphonates tend to accumulate in recalcitrant dissolved organic matter, aminophosphonates do not. Thus, we hypothesised unknown pathways for the uptake of...

Background and aims: Mineral elements have many essential and beneficial functions in plants. Phosphorus (P) deficiency can result in changes in the ionomes of plant organs. The aims of this study were to characterize the effects of P supply on the ionomes of shoots and roots, and to identify chromosomal quantitative trait loci (QTLs) for shoot an...

Modifications of root system morphology and architecture are considered important strategies of plant tolerance to phosphorus (P) deficiency. However, the effect of culture system on the responses of root traits to P deficiency is not well documented. In this study, the responses of root traits to P deficiency were recorded in a Brassica napus doub...

Global food production is reliant on the application of finite phosphorus (P) fertilisers. Numerous negative consequences associated with intensive P fertilisation have resulted in a high demand to find alternative sustainable methods that will enhance crop P uptake. Bacteroidetes, primarily from the genus Flavobacterium, have recently been shown t...

Understanding how plants respond to nitrogen in their environment is crucial for determining how they use it and how the nitrogen use affects other processes related to plant growth and development. Under nitrogen limitation the activity and affinity of uptake systems is increased in roots, and lateral root formation is regulated in order to adapt...

AimsPotato (Solanum tuberosum L.) has a large phosphorus (P)-fertiliser requirement. This is thought to be due to its inability to acquire P effectively from the soil. This work tested the hypothesis that early proliferation of its root system would enhance P acquisition, accelerate canopy development, and enable greater yields. Methods Six years o...

Background There are numerous systems and techniques to measure the growth of plant roots. However, phenotyping large numbers of plant roots for breeding and genetic analyses remains challenging. One major difficulty is to achieve high throughput and resolution at a reasonable cost per plant sample. Here we describe a cost-effective root phenotypin...

In soils, phosphorus (P) exists in numerous organic and inorganic forms. However, plants can only acquire inorganic orthophosphate (Pi), meaning global crop production is frequently limited by P availability. To overcome this problem, rock phosphate fertilisers are heavily applied, often with negative environmental and socio-economic consequences....

Plants are extremely versatile organisms that respond to the environment in which they find themselves, but a large part of their development is under genetic regulation. The links between developmental parameters and yield are poorly understood in oilseed rape; understanding this relationship will help growers to predict their yields more accurate...

In soil, bioavailable inorganic orthophosphate is found at low concentrations and thus limits biological growth. To overcome this phosphorus scarcity, plants and bacteria secrete numerous enzymes, namely acid and alkaline phosphatases, which cleave orthophosphate from various organic phosphorus substrates. Using profile hidden Markov modeling appro...

Background Mineral nutrient uptake and utilisation by plants are controlled by many traits relating to root morphology, ion transport, sequestration and translocation. The aims of this study were to determine the phenotypic diversity in root morphology and leaf and seed mineral composition of a polyploid crop species, Brassica napus L., and how the...

Table S1. A rank‐abundance profile of the identified proteins in the exoproteome of Pseudomonas putida BIRD‐1. Table S2. A rank‐abundance profile of the identified proteins in the exoproteome of Pseudomonas fluorescens SBW25. Table S3. A rank‐abundance profile of the identified proteins in the exoproteome of Pseudomonas stutzeri DSM4166. Table S...

Fig. S1. Proportion of the extracellular and intracellular proteins detected in the four protein fractions extracted during this study. Only the top‐60 most abundant proteins were included in the analyses. The values displayed are taken from Pi‐deplete and Pi‐replete cultures. Results presented are the mean of triplicate cultures. Fig. S2. The abu...

A high-density SNP-based genetic linkage map was constructed and integrated with a previous map in the Tapidor x Ningyou7 (TNDH) Brassica napus population, giving a new map with a total of 2041 molecular markers and an average marker density which increased from 0.39 to 0.97 (0.82 SNP bin) per cM. Root and shoot traits were screened under low and ‘...

Bacteria that inhabit the rhizosphere of agricultural crops can have a beneficial effect on crop growth. One such mechanism is the microbial-driven solubilisation and remineralisation of complex forms of phosphorus (P). It is known that bacteria secrete various phosphatases in response to low P conditions. However, our understanding of their global...

Background and aims: Root traits can be selected for crop improvement. Techniques such as soil excavations can be used to screen root traits in the field, but are limited to genotypes that are well-adapted to field conditions. The aim of this study was to compare a low-cost, high-throughput root phenotyping (HTP) technique in a controlled environm...

Background and Aims: Phosphate (Pi) is one of the most limiting nutrients for agricultural production in Brazilian soils due to low soil Pi concentrations and rapid fixation of fertilizer Pi by adsorption to oxidic minerals and/or precipitation by iron and aluminum ions. The objectives of this study were to quantify phosphorus (P) uptake and use ef...

Flooding is a major constraint to rice production in many areas. The unpredictable nature of flooding events, including varying depth, duration and timing make it difficult to manage. Changes in the global climate are predicted to alter weather patterns resulting in more frequent heavy storms and sea level rise, which will exacerbate the problem. T...

Background Crops require adequate nutrition for the production of food, fibre and fuel, but soil conditions often limit the ability of crops to acquire mineral nutrients. To address this, mineral nutrients can be applied as inorganic or organic fertilisers to the soil or as liquid fertilisers to foliage. However, production and use of fertilisers...

Although Ca transport in plants is highly complex, the overexpression of vacuolar Ca 2+ transporters in crops is a promising new technology to improve dietary Ca supplies through biofortification. Here, we sought to identify novel targets for increasing plant Ca accumulation using genetical and comparative genomics. Expression quantitative trait lo...

Superimposed on the underlying DNA sequence of plants and animals is a series of epigenetic marks that can provide considerable agility in terms of modulating gene expression, ontology, susceptibility to disease and response to the environment. Understanding the epigenetic processes corresponding with these functions may unlock hidden traits of agr...

Increased concern about climate stability and reduced land availability is placing more emphasis on the need to develop resilient crop plants that have an appropriate level of plasticity in response to variable or challenging environmental conditions. Brassica genomes provide useful models for understanding the contribution that complexity and exte...

High soil phosphorus (P) concentration is frequently shown to reduce root colonization by arbuscular mycorrhizal (AM) fungi, but the influence of P on the diversity of colonizing AM fungi is uncertain. We used terminal restriction fragment length polymorphism (T-RFLP) of 18S rDNA and cloning to assess diversity of AM fungi colonizing maize (Zea ma...

Phylogenetic tree showing relationship of sequences from maize and soybean to described species.

Clones sequenced from maize and soybean.

Onions have evolved as a storage organ in order for the plant to overwinter. During the transition of endo-dormancy (dormancy) to eco-dormancy (sprout suppression) to sprout growth, the bulb undergoes change from sink organ to source in order to sustain cell division in the base plate. The mechanisms controlling these stages of development have yet...

Onion is regarded as non-climacteric. In climacteric produce, exogenous ethylene generally results in ripening-related changes, however in onion, ethylene can suppress sprouting. The ethylene binding inhibitor, 1-MCP can also suppress sprout growth in onion although it is unknown how ethylene and 1-MCP elicit the same response. In this study, 'Sher...

Background and AimsPhosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quant...