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SEERAD Programme of Agricultural, Biological and Related Research 2002-2003

2.2 Plant Physiology

Research in this category falls into two main areas, either research at the sub-cellular and molecular levels (Theme 2.2.1), or research undertaken at the level of the whole plant (Theme 2.2.2).

2.2.1 Plant Molecular Physiology

Improving our understanding of the basic biology of key developmental stages in the mandate crop plants should help identify factors that limit sustainable production. One biological process being studied is the investigation of malting quality in barley. Fruit ripening and the understanding of biochemical controls of vitamin C (ascorbic acid) synthesis are also a strength in this part of the programme and there is related work under Theme 2.2.2 on the biodiversity of antioxidant status in soft fruit germplasm. The Department has commissioned research into a key area of gene expression namely, the processes of "transcription" which is the production of the message, mRNA, from the gene and the subsequent processing of this message, "mRNA splicing". Cell biology research includes work on transport of large molecules between plant cells and may be relevant to biotech end users. Information generated by this research will improve general scientific understanding, since it describes processes that are common to all plants, and could also have potential biotechnological application.

2.2.2 Whole Plant Physiology

A strength of the SEERAD-funded plant physiology programme lies in the depth of knowledge and expertise available to investigate root growth (turnover and mortality). This work has been expanded by the application of new techniques, such as using stable isotopes ( ¹⁵N). Two new projects examine links between root structure, architecture and senescence. Ultimately this research will inform policies for better use of land, for example, by forestry or for coppicing, as well as grassland for grazing. Some of the biochemical work on potato tuber quality and soft fruit antioxidant status are linked with complementary projects listed under 2.1.3, where the genetic characterisation of the same material is being undertaken. Research on a key antioxidant, vitamin C, is listed under Theme 2.2.1. Other aspects of plant-derived food quality are also being studied with the aim of enhancing the nutritional quality of potato and barley. Recently these biochemical approaches have been expanded to include metabolomics research, where high-throughput biochemical screening is being used to understand key developmental processes in plants. At the whole plant level, research is looking at nitrogen acquisition by roots and nitrogen remobilisation within trees, for example, prior to spring bud break. Also included in this section is research on barley crop physiology, which is funded jointly with the Home-Grown Cereals Authority (HGCA) where the growth of the crop is being linked with agronomic practice.

2.3 Novel Plant Products

The main thrust of the novel plant products programme lies in the "OVERCOAT" plant virus expression system, which should allow cheap, rapid and safe production of high-value pharmaceutical proteins (vaccines and enzymes) in plants. This research builds on the platform of basic virus research previously funded by the Department. The main project was funded through the CHABOS initiative (Committee of Heads of Agricultural and Biological Organisations of Scotland) and will explore delivery routes for plant virus expressed peptides and proteins. Other SEERAD-funded research focuses on high value essential oils, including those from rosemary and bog myrtle with roles as valuable antioxidants. A collaborative project has been funded involving the Scottish Crop Research Institute (SCRI), the Royal Botanic Garden Edinburgh (RBGE) and the Strathclyde Drug Research Institute (SDRI) which aims to screen bryophyte and Solanum collections for the presence of novel bioactive compounds.

2.4 Plant Pathology

Crop losses due to pests and diseases represent one of the greatest problems faced in arable and horticultural production. SEERAD-funded pathology research aims to improve the sustainability of Scottish agriculture. The research is focused on strategies that will ultimately deliver improved, sustainable and benign methods of pest and disease control. If crop pests and diseases are not controlled then there is a loss of quality and/or yield of the harvestable product.

2.4.1 Fungi & Bacteria

SEERAD-funded research on fungi and bacteria is targeted on understanding the interactions that occur between the pathogen and host before and during an infection. The genetic mechanisms controlling a pathogen's host range and virulence (for example, the range of cultivars it can infect and the severity of the diseases they cause), and the physiological mechanisms underlying pathogenicity are often poorly understood, yet are central to studies on host resistance and to the breeding of new plant cultivars with increased and durable forms of resistance. SEERAD-funded research on fungal pathogens focuses on the species of Phytophthora, which cause a diverse range of plant diseases, including late blight on potatoes, raspberry root rot and red core of strawberries, and on Spongospora subterranea, which causes powdery scab on potatoes. Some of this research is funded jointly with the British Potato Council, thus ensuring that the outputs will be of use to the potato growers. A further project, which studies a range of fungal diseases on potato tubers and which aims to improve seed health during storage, has been commissioned through the SAPPIO-LINK programme. The main bacterial pathogen studied is Erwinia carotovora, which causes blackleg and stem rot of potatoes. Latent blackleg infection of seed tubers is a common disease in the UK, and infection can damage the reputation of Scottish seed stocks destined for export. Research on Phytophthora and Erwinia form the key foci for the Department's plant pathogenomics research. A SEERAD Senior Research Fellowship (FEL) has been funded to look at Phytophthora genomics. In addition, the Department has commissioned research jointly with BBSRC which compares pathogenicity in Phytophthorainfestans with that in another oomycete, Peronospora parasitica, which causes downy mildew. This research involves a collaboration between scientists at SCRI and the Horticulture Research International. The research links into other European and overseas groups. A collaborative research programme has been funded between the Scottish Crop Research Institute (SCRI) and the Moredun Research Institute (MRI) to develop a platform in bacterial genomics. Within this programme the genomes of two bacterial pathogens Erwinia carotovora and Chlamydophila abortus will be sequenced. This section also includes work on mycorrhizal fungi, which form beneficial, symbiotic associations with plants.

2.4.2 Viruses

SEERAD-funded research into plant viruses contributes significantly to the UK science base in this area, and is also of international significance. Plant viruses are obligate parasites and few can survive outside living tissue. The associations between viruses and their hosts are complex. While some viruses are passively spread, most depend on vectors for their transmission between plants, particularly insects, mites, nematodes and fungi. Research therefore needs to take account of the structure and physiology of viruses, their vectors and their host plants, and the interactions between all three. SEERAD-funded research concentrates on viruses which infect potatoes and soft fruit. Detailed examination can sometimes provide insights into features of the nucleotide sequences, which are responsible for the observed biological properties of a virus, for example, its replication (amplification), and movement within a plant. Both local (cell-to-cell) and long-distance (leaf-to-leaf) movement of major potato viruses are being studied.

2.4.3 Nematodes

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are major pests of potatoes in Britain. G. rostochiensis used to be the dominant species, and, in the past, long rotations limited the build up of cyst populations in ware land. However, the introduction of potato cultivars carrying the H1 gene for resistance to G. rostochiensis, combined with the heavy use of nematicides, enabled rotations to be shortened. This practice led to a widespread increase in G. pallida populations, against which the potato H1 resistance gene is ineffective. A fuller understanding of the diversity, biology and genetics of cyst forming nematodes, including an understanding of the molecular basis of virulence are needed if breeders are to develop resistant cultivars. Two projects describe novel approaches to develop transgenic resistance in potato to PCN. In addition, ecological research has been commissioned on a new threat to horticulture and agriculture, the New Zealand flatworm.

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