Wheat is an important agricultural crop in the United Kingdom. Greenfly (aphids) can reduce grain quality and yield by direct feeding and transmission of diseases to this crop and they need to be controlled. The Department of the Environment, Food and Rural Affairs and the agricultural industry have invested much effort into controlling these pests and others, including fungi and weeds, with pesticides, but there is concern that excessive use of such agents could harm the environment and pass into the human food chain. Attempts have been made to reduce pesticide use by transferring insecticidally active agents into wheat from other organisms by genetic modification. However, many plants species can mount their own defence by producing small amounts of natural chemicals that can deter invading pests. We plan to exploit this property to develop alternative, more environmentally compatible pest resistance strategies for cereal crop plants. Specifically, we are interested in the hydroxamic acids (HAs), a family of compounds produced in wheat and other cereals that defend plants against pests. These chemicals reduce the development of aphids and may deter other insects and weeds. The potential of HAs to control pests in cereals has been intensively studied and, the pathway involved in their biosynthesis within the plant is now known. We plan to examine HA production in wheat varieties that have varying degrees of resistance to pests and disease to confirm that these compounds do indeed have a significant role in aphid resistance. Besides differences in HA levels in these varieties that can be detected under normal conditions, we will exploit ways of increasing production in the wheat by investigating the action of other natural plant chemicals, called plant activators, which can cause increased production in the defence chemistry of plants. In this way we hope to develop means to switch on the production of the plant's natural defence compounds only when necessary, thereby conserving the plant's energy and reducing the development of pest resistance. In addition to demonstrating the effect of high levels of HAs on aphids, we will also investigate their effects on other insects such as gout fly, and to weeds such as black-grass. We know the genetic backgrounds, or pedigrees, of the varieties that we have chosen to study, so we will be able to identify the original parents of wheat varieties that produce high levels of HAs or that are capable of increasing production by the action of the plant activators. Therefore, by the end of the project, working under more practically oriented funding programmes, we will develop our findings together with industrial partners to produce new varieties of wheat that will be able to protect themselves more effectively in the face of a pest attack. This will involve breeding techniques to introduce high production of HAs into wheat plants that can grow in the United Kingdom. The HAs are naturally produced in the roots and green tissue of the plant and so do not influence the nutritional value of the seed from which we make flour for food production, but we will ensure that high HA producing varieties do not show detectable amounts of HAs in the grain. However, full human risk assessment would be part of the work done following this project. Although we can only speculate on how valuable increased HA production will be in developing new means for controlling pests on wheat, we know that HAs are antagonistic to a range of pests, weeds and fungal pathogens. We have established chemical analytical and molecular biological methods for analysing the natural chemicals and associated genes involved in the production of these materials and we have, in preliminary studies, demonstrated increased production of HAs with the natural plant activator chemical, cis-jasmone.

Plants require sulfur for growth, but much of the sulfur in agricultural soils is present in a bound form ('sulfate esters') that can be used by some bacteria, but not directly by plants. Many of these bacteria live in close association with plant roots, forming dense communities on the root itself and in the soil immediately surrounding it (the 'rhizosphere'). They are actively nourished by the plant, which uses photosynthesis to produce sugars and amino acids that are released from the root to promote bacterial growth, and in return many of these root-associated bacteria promote plant growth by mobilizing mineral nutrients (including sulfur) from the soil for plant utilization. This interaction relies on a network of communication between plants and microbes, with specialist groups of bacteria responsible for certain functions in the soil, and the plant using specific signals to stimulate these bacteria to produce the nutrients it needs. This project will examine two main aspects of sulfur metabolism in the rhizosphere. First, we will investigate which bacterial families are important in promoting the release of bound sulfur from the soil for plants to use. Because many soil bacteria cannot be cultivated in the laboratory, we will start by establishing a database of sulfate ester utilization genes from cultivable soil bacteria that can metabolize sulfate esters. We will then use this database to investigate the overall microbial community in the rhizosphere of the three most important agricultural crops that are grown in the United Kingdom, wheat, barley and oilseed rape. This will provide vital new information to identify the most important bacterial species for sulfate ester metabolism in the rhizosphere of our major crops. To increase the predictive power of this data we will then validate these findings in the rhizospheres of the most commercially important cultivars of these crops, on field trial sites across the UK from Penzance to Aberdeen. Having identified the bacteria that are most active in soil sulfate ester metabolism, the next step is to characterize how plants control their activity. Our preliminary findings show that plants can promote the production of the most important bacterial enzyme for sulfate ester metabolism, arylsulfatase, and can also stimulate its activity once produced. The mechanisms by which these two processes occur will be investigated in a range of plants, including both crops and other species, by isolating the Arabidopsis protein that is responsible for stimulating arylsulfatase activity, and taking the first steps in elucidating how plant root exudates can override the normal bacterial control of arylsulfatase production. The results will provide new insights into how plants control nutrient cycling in the rhizosphere environment, with potential applications in promoting sustainable agriculture in the United Kingdom.

Resource use efficiency can be improved by either maintaining yield with lower crop inputs (e.g. fertiliser or pesticides) or increasing yield with the same, or reduced, crop inputs. Increasing yield is likely to be the most sustainable approach given the need to ensure global food security and the limited scope for expanding the cropped area. A recently completed LINK project (LK0958) identified regions of chromosomes 3A and 7D (known as quantitative trait loci or QTL) that were associated with increased resource use efficiency resulting from yield increases of 0.3 to 0.4 t/ha (at a given level of crop inputs). A smaller yield effect QTL was also found on chromosome 6A. These QTL were also associated with a lower resistance to lodging primarily as a result of greater height, and also due to a smaller stem wall width and root plate spread. Several other height QTL were found which did not affect yield. It was also shown that some height QTL were twice as responsive as others to shortening by plant growth regulator (PGR) chemicals. These discoveries offer the prospect of increasing resource use efficiency by combining QTL for increased yield (at a given level of inputs) with QTL for increased lodging resistance (through crop shortening), as well as by improving lodging control through better targeting of PGRs. However this is not currently possible because the genetic markers identified in LK0958 are not close enough to the specific genes located within the QTL region for the breeders to reliably identify the presence of the positive genes in a range of genetic backgrounds. This project aims to increase resource use efficiency by developing reliable genetic markers and a physiological understanding for QTL that increase yield and lodging resistance without increasing the crop's requirement for inputs. This will be achieved by: 1) Developing varieties that differ only for the region of chromosome with the QTL for resource use efficiency (near isogenic lines) which will be used to achieve objectives 2 and 3, 2) Identifying more reliable genetic markers for these QTL, 3) Understanding the physiological mechanisms by which these QTL act and quantifying effects on resource use efficiency and greenhouse gas emissions, 4) Investigating which yield and height QTL are in current varieties and the scope for combining them to increase resource use efficiency through greater yield and reduced lodging risk, and 5) Quantifying the responsiveness of the different height QTL to different PGR active ingredients. A major component of this project will involve cloning the gene within the height/yield QTL on chromosome 3A to produce a 'perfect' genetic marker. New markers will be developed for the other QTL which will have much greater reliability due to their closer proximity. This will allow breeders to design crosses to achieve the optimum combination of height and yield QTL in a given cross. Understanding the physiological mechanisms by which the QTL affect yield (e.g. is sink (grains/m2) or source (supply of assimilate) increased) will help to identify the crop management practices required to achieve these greater yields with minimum crop inputs, and thereby increasing resource use efficiency. Genetic markers for the height QTL will also be used to predict which varieties will respond most to PGRs with different modes of action. As PGRs are used prophylactically on the majority of wheat crops this will allow their use to be avoided on unresponsive varieties. It is estimated that the project will increase resource use efficiency by 10% through greater yields and better lodging control. The project will also complement the Defra funded Wheat Genetic Improvement Network (WGIN) by phenotyping the near isogenic lines (NILs) produced within the network and producing new NILs that can be added to the network's genetic resources.

Eyespot is the most important disease of the stem base of cereals in the UK causing £12-20 million per annum in lost yield, in addition to significant expenditure on fungicides. Only three sources of resistance to eyespot are known to be present in modern wheat cultivars. The most potent of these is the gene Pch1, which originates from a wild grass. This resistance was introduced into wheat by conventional crossing, replacing a large segment of one of the wheat chromosomes with the equivalent portion from the wild grass (so-called 7DV segment). The two other eyespot resistances (Pch2 and QTL5A) both come from the variety Cappelle Desprez but they both have only moderate effects on eyespot resistance. Wheat varieties carrying the 7DV segment are highly resistant to eyespot and it has also been observed that varieties containing the 7DV segment have a higher grain protein content. Unfortunately varieties carrying this 7DV segment suffer a yield penalty and it is only relatively recently that Pch1 carrying varieties have been developed that also possess high yield potential. We have shown that most of these varieties carry the full size original segment and so it appears that the negative yield effect of the 7DV segment is compensated by other factors in these new varieties. Efforts to separate the desirable eyespot resistance and protein content traits from the deleterious yield effect have been seriously hindered by two factors: an apparent reduction in recombination between the native wheat chromosome and the 7DV segment and a lack of suitable DNA markers. However, recent advances in marker technology have made it possible to characterise the 7DV segment and identify lines carrying much smaller segments. In this project we aim to isolate the Pch1 gene and also identify the part of the7DV segment that confers the increased grain protein content. This will enable plant breeders to develop wheat varieties that carry the desirable parts of the 7DV segment (Pch1 eyespot resistance and the part responsible for increased grain protein content) without the undesirable (yield penalty) parts. Pch1 lies in a region of 7DV that is similar to that of the moderately effective eyespot resistance gene Pch2 from Cappelle Desprez. These two resistances are potentially due to 'sister' genes and we will determine whether this is the case or whether they are in similar but not identical positions.

Bio-lubricants have both environmental and technical advantages over their counterparts derived from mineral oils. In addition to being renewable, they are biodegradable, have lower volatile emissions and low environmental toxicity. They provide superior anti-wear protection and exhibit reduced combustibility. In addition, bio-lubricants have lower coefficients of friction, which results in reduced energy costs for equipment in which bio-lubricants as used. Although vegetable oils are used in blending some less stressed lubricants, their thermal stability is inadequate for the majority of applications as a consequence of the presence of excessive polyunsaturation of their constituent fatty acids. In view of the poor stability of conventional refined rapeseed oil, lubricant blenders currently favour the use of synthetic esters with a high renewables content of the production of the more stressed lubricant types; this more expensive base oil currently inhibits uptake of bio-lubricants by end users. Rapeseed oil has many physical and chemical properties that are advantageous for base oil for the lubricants industry. However, the total content of polyunsaturated fatty acids remains too high and the resulting instability is the principal barrier to its widespread use. The target set by the industry is reduction to less than 5% total PUFAs, whilst retaining the other desirable physical and chemical properties of rapeseed oil. To be economically competitive, some yield penalty in the crop and increased processing costs can be tolerated, as its principal competitor in the market place, low PUFA sunflower oil, is presently priced at up to $120/tonne more on the commodity markets. Nevertheless, the approaches we propose should result in little, if any, yield loss from fully developed varieties. The purpose of the project is to underpin the development of oilseed rape varieties for the production of oil for use in the lubricants industry. A key knowledge gap is an understanding of how to substantially reduce the content of polyunsaturated fatty acids in rapeseed oil without reducing the oil yield of the crop. We will address this knowledge gap and enable establishment of a closed supply chain. This involves: (a) The genetic improvement of oilseed rape by mutagenesis of specific genes in order to produce, from a high-yielding winter crop, oil very low in polyunsaturated fatty acids. (b) Assessment of the physical properties of the oil produced in order to validate its utility. (c) Provision of characterised oilseed rape lines to the breeding industry for the development of cultivars. (d) Catalysing assembly of a supply chain. The strategy is non-GM, so we anticipate no barriers to the widespread utilization of the resultant varieties in the UK.