Rothamsted Research

The decomposition of organic matter is a critical process to the functioning of terrestrial ecosystems. This process is largely driven by saprotrophic (decomposer) fungi in soil and plant litter. Saprotrophic fungi therefore have pivotal roles in the release of carbon (C) from terrestrial ecosystems, in the form of CO2 (a climate-forcing gas), to the atmosphere. Currently, little is known of the specific roles of individual fungal species, i.e. functional diversity, in the degradation of particular C components in the sub- and Maritime Antarctic. The first step in characterising functional diversity is to identify the soil C components (fractions, particle sizes and ages) with which decomposer fungi in soil are associated. Establishing baseline fungal taxonomic and functional diversity and characterizing the soil C components, central aims of this project, are fundamental to understand the impacts of environmental change on Antarctic ecosystems. Sub and Maritime Antarctic soils are being studied because soils in these regions have relatively high stocks of C due to the slow decomposition of organic matter and the tundra vegetation present. The potential temperature responses of these soils and the C fractions they contain are also important to understand because the terrestrial Maritime Antarctic has been warming rapidly. The temperature sensitivity of young and older C fractions in releasing CO2 to the atmosphere is much debated, particularly for peatlands and permafrost soils, such as those that occur in the sub- and Maritime Antarctic. We will determine the associations of specific fungal taxa with specific organic fractions in the field at three sites in the sub- and Maritime Antarctic, and characterise by age and organic geochemistry, the C components of these fractions. In the laboratory, the specific C fractions mineralised by key species of fungi will be determined, together with responses to temperature increases and freeze-thaw cycles.

1) To annotate the full length gene encoding the sequence of the A. pisum sodium channel from the genome sequence, identify the possible splice variants for the final protein product and clone the full length cDNA from A. pisum and/or Myzus persicae (either as one or several clones). 2) To produce a homology model of the Myzus persicae sodium channel and use this to identify the locations of mutations known to affect binding of pyrethroids to the sodium channel of aphids (it is highly likely that there will be very strong similarity between the channels in different aphid species) and hence locate critical amino acids involved in binding at this site. 3) To produce further models for regions of the aphid channel equivalent to the binding sites of ligands of mammalian channels and thus identify critical amino acids likely to be involved in binding of this type of ligand (especially regions known to be involved in binding of both insecticides and local anaesthetics). 4) To over-express aphid sodium channels in the yeast Pichia pastoris system for future compound validation. 5) To use the information obtained to design new hyperactive insecticidal molecules and those likely to overcome resistance and/or be more selective for insect channels (the synthesis of such molecules would be beyond the scope of the current project).

The need to reduce fossil fuel contributions to climate change is the most significant and pressing challenge of this century. The mission of the BBSRC Sustainable Bioenergy Centre is to provide the underpinning research to help develop economically, socially and environmentally sustainable lignocellulose derived fuels which have a positive impact on climate change and energy security. The overall aim of the Perennial Bioenergy Crops Programme within BSBEC is to underpin the development of sustainable biofuels by optimising biomass feedstocks from perennial (non-food) biomass crops whilst maximising energy savings and minimising greenhouse gas (GHG) emissions. The Programme has scientific, integrational and capacity building specific objectives and, together with the other five Programmes that comprise the BSBEC, aims to bring focus and leadership to the UK's development of the biology and biotechnology that will generate transport fuel from the ligno-cellulosic fraction in plants. Specific objectives are: 1.Scientific objectives: To optimise: (1) Biomass yield in short rotation coppice (SRC) willow and Miscanthus; and (2) The accessibility of the carbon for conversion in these two crops, whilst maximising energy savings and minimising GHG emissions. 2.Integrational objectives: To integrate fundamental genomic, crop, plant, microbial, biochemical and bioprocessing sciences by linking with other programmes in the BBSRC Sustainable Bioenergy Research Centre, and scientific community, as appropriate 3.Capacity building objectives: To train a new generation of scientists in the necessary R&D skills and build capability and capacity in bioenergy research.

Insect pests of crops are often controlled using chemical insecticides. Unfortunately over time many pests have evolved resistance to the insecticides used for control. Insects have been shown to develop resistance in two main ways. Firstly by changes in the protein that the insecticide binds to which means that it is no longer as sensitive to the toxic effect of the insecticide and secondly by increased production of enzymes that break down or bind to the insecticide and render it ineffective. In this proposal we aim to study insecticide resistance in two important crop pests the peach potato aphid (Myzus persicae) and the brown planthopper (Nilaparvata lugens). M. persicae is a major pest on a range of crops in the UK and Europe and N. lugens is a major pest of rice crops in Asia, both cause damage to plants through direct feeding and the transmission of viruses resulting in high economic losses. Both of these crop pests have evolved resistance to many of the insecticides used for their control and the main chemical class currently being used is the neonicotinoids. However reports of resistance to this insecticide class have recently been described. Biochemical studies have shown that this resistance is likely to be caused by increased production of enzymes that break down the insecticide, in particular a group of enzymes called cytochrome P450 monooxgenases (P450s). P450s are a class of enzymes with many functions including the breakdown of toxins and insects have been found to have between 46-143 P450 genes, each producing a different enzyme. Insect pests can become resistant to insecticides by increasing the amount of one or more of the P450 enzymes they produce. In this project we aim to examine if resistance in M. persicae and N. lugens to neonicotinoids is caused by over-production of P450s and determine which P450s are involved and why they are over-produced. It is not easy to study the large gene families involved in metabolic resistance however recent advances in the field of genomics (the study of genes and their function) and new associated technologies means that it is now more feasible. This study will exploit these new resources to identify P450 genes in the target pest species. These include the genome (the entire DNA content of an organisms) sequences of a number of insect species (including an aphid), expressed sequence tags or ESTs (small pieces of DNA sequence usually 200 to 500 nucleotides long that are generated by sequencing either one or both ends of an expressed gene) and affordable high-throughput sequencing technologies that allow many hundreds of millions of bases (a unit of DNA) of sequence to be determined in a matter of hours. The identified P450 genes will then be studied using new molecular methods that allow determination of the levels of expression of genes into RNA and protein. The technique RNA interference (the introduction of double-stranded RNA into a cell to inhibit the expression of a gene) will be used to silence P450 genes and therefore examine their role in resistance. Finally the P450 genes will be cloned and expressed as protein to see if they break down or bind to insecticide. When the specific P450s involved in resistance in these crop pests have been identified we will develop diagnostic tools to monitor insect populations for resistance. These are an essential requirement of resistance management strategies which aim to slow or prevent the development of resistance. Prolonging the life of insecticides by managing resistance is vital as there are only a limited number of insecticides available for control and proposed new legislation on pesticides from the European Parliament will dramatically cut the availability of insecticides for use in agriculture. This project will be carried out in collaboration with partners in agrochemical companies and the Insecticide Resistance Action Group to ensure the findings of this study can be rapidly exploited.

The novel research challenges addressed here are centred on new technologies for understanding process and mechanisms of the interaction between grasslands and water, with particular emphasis on phosphorus. The work is organised into four main activities on organic phosphorus, relationships between wetting and drying and nutrient release, grasses and their roots for mitigating diffuse pollution and determining high resolution temporal patterns in the quality of grassland waters.