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|2010 -||Reader||Department of Biology, University of York|
|2002 - 2010||Senior research fellow||Department of Biology, University of York|
|1998 - 2002||Research Fellow||Department of Biology, University of York|
|1992 - 1998||Post-doc||Department of Biology, University of York|
|1990||PhD||University of Groningen|
|1984||MA||University of Groningen|
Research centres on plant nutrition and stress. Plant nutrients and toxic minerals are typically present in ionic form and we study molecular mechanisms of ion uptake and translocation. Studies are conducted to elucidate how K+ is taken up and distributed throughout plants, through identification and characterisation of K+ membrane transporters. Plant stress research focuses on detrimental effects of salinity, a global and increasing problem, and in particular on molecular pathways for Na+ uptake and how these are regulated by cyclic nucleotide signalling. More recently, investigations have started to identify and characterise membrane transporters involved in the uptake and distribution of arsenic in Arabidopsis and rice. Techniques to study these subjects include: electrophysiology, transcriptomics and (phospho)proteomics.
We discovered types of non selective ion channels in roots of Arabidopsis that are regulated by cyclic nucleotides and that these second messengers play important roles in plant salt tolerance and potassium nutrition. We were the first to report on the function of NIP aquaporins in plant arsenic uptake.
|Research Student||Izhar Ahmad||Improving rice K nutrition and salt tolerance|
|Research Student||Afroza Begum||The role of K channels in stomatal functioning|
|Research Student||Emma Lindsay||Improving rice arsenic resistance|
|Research Student||Radwa Mohamed||Improving drought and salinity tolerance in crops|
|Research Student||Juan Patishtan||Identification and characterisation of salt and drought tolerant rice cultivars|
|Visiting post doctoral fellow||Dr Haiou Wang||Improving plant arsenic tolerance|
|Technician||Li Hong Cheng (50% FFTE)|
Plant Arsenic Biomonitors (2015-16)
Arsenic (As) is a Class 1 carcinogen with no minimum threshold intake. Arsenic poisoning affects more than 100 million people worldwide, particularly in south Asia. Recent studies have identified foods, especially rice, as an important source of inorganic As intake by humans posing a potentially significant health risk for people on a rice-based diet living anywhere in the world1,2). The main reason for this phenomenon is the much greater efficiency with which rice accumulates As, compared to other cereal crops. In the worst affected areas, build-up of As in soil has also resulted in significant yield losses due to As toxicity. Since rice is a staple food for about half of the world population, there is an urgent need to develop strategies to limit As contamination, and an early warning system to signal the onset of As accumulation would be highly beneficial.
Objectives: We will generate crop plants that to report on their As status. To accomplish this we will use an arsenic sensor and a reporter. For the sensor, we will make use of the promoter of a gene that responds to As, the cytochrome P450 (Os01g43710) is an excellent candidate, and link this to a gene that when expressed provides an easily distinguished colour marker as reporter. For the latter, anthocyanins (red-purple pigments) are ideal. This approach will result in plants that will turn red whenever As toxicity presents itself.
Co director: Michael Schultze
Improving Arsenic tolerance in Rice (2015-16)
Project and background: Arsenic (As) is a metalloid, which occurs ubiquitously in nature. It is found predominantly as inorganic arsenate and arsenite. Arsenate, as a phosphate analogue, has detrimental effects on phosphate metabolism but arsenite is even more toxic due to its high reactivity with sulfhydryl groups of proteins. As such As is classified as a group 1 carcinogen and there is large concern about human contact with As which occurs through drinking of contaminated water and via the food chain because in many areas crop growth depends on usage of As contaminated irrigation water. It is estimated that more than 100 million people are exposed to toxic levels of As.
Arsenic contamination through consumption of crops is particularly prevalent where rice is concerned: Rice is the staple of billions, it is produced in many south east Asian countries that have high levels of As in their aquifers, and rice translocates a relatively high proportion of As to its edible part, the grain.
No specific As efflux mechanism has been identified in plants. You will use a GWAS (genome wide association studies) approach to identify As efflux mechanisms. To assess if As efflux in plants can be augmented, and whether this has positive effects on plant growth, you will express heterologous systems such as ACR3 from Saccharomyces cerevisiae and/or use transgenic approaches (e.g. overexpression, genome editing) to alter activity of putative As efflux mechanisms in rice. Transgenic rice will be evaluated for As tolerance and As content level in various tissues such as roots, leaves and in seeds. This project will train the candidate in whole plant physiology, molecular biology and crop biotechnologies such as cereal transformation.
Improving Rice Salt and Drought Tolerance (2015-16)
Background: Salinity and drought stress are a major and global detriment to agricultural production. Their negative impact on crop production is exacerbated by sensitivity of major crops such as wheat and rice, a growing human population and climate change. For both salt and drought stress, the manipulation at the transcript level of single transporter genes in rice has shown that its tolerance can be significantly improved in this way. This includes altering expression of K+ transporters such as TPKs and AKTs and Na+ transporters such as NHXs and HKTs. However, the multigenic nature of salt and drought stress means that the expression of multiple transporters needs altering to optimise stress resistance. Such ‘stacking’ or ‘pyramiding’ of traits has hardly been attempted in rice abiotic stress.
Work plan and aims: This project envisages combining the positive effects that were observed by the manipulation of single genes to further improve salt and drought tolerance in rice. We will focus initially on genes for which transgenics are already available in the lab (vacuolar channels TPKa and TPKb, the K+ uptake and translocation systems AKT1 and SKOR and the Na+ transporter HKT2;1). Lines will be crossed and/or retransformed to generate multiple transgenics. Retransformation may include the use of tissue specific promoters. State of the art genome editing will also be applied to alter activity of specific genes. Using growth assays and mineral content analysis, lines will be assessed for synergistic phenotypes regarding tolerance to salt and drought stress.