Probing mechanisms of pathogen effector recognition by plant Resistance proteins to elevate defence gene activation

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Plant diseases contribute greatly to annual crop losses and pose a real threat to food security worldwide. Indeed, many other food- and cash-crops such as wheat, rice, maize, soybean, barley, potato, cotton, canola, and others are susceptible to many different types of diseases. Over a million people died during the Great Irish Famine in the 19th century as the result of a potato blight epidemic. Currently, the world's most popular fruit, the Cavendish banana, is under threat of extinction due to infection by highly virulent fungal pathogens [1]. Recently, the reduction of citrus yields also largely affects the manufacture and economy, due to the infection of 'tree-killing' bacteria [2].Plant diseases also threaten the environment. There are >80 million Ash trees growing in UK forests and along neighborhood roads currently under threat of Ash dieback disease, caused by a relentless fungal pathogen [3]. Recent estimates project that 75% of Ash trees in the south and east England will be infected by this disease by 2018 [3]. Battling diseases that affect our crops and trees is a global challenge requiring the work of scientists in both academia and industry, as well as the work of policy-makers and government.Pathogens are capable of infecting plants and causing disease largely because they can suppress plant immune systems. Thus, only when we clearly understand plant immunity will we be able to offer sustainable solutions to diseases that affect our crops.Scientists in the UK have always been seeking knowledge of how to achieve durable and sustainable disease resistance for crops. Understanding the molecular mechanism by which plants establish full resistance against various pathogens is essential to design better strategies for protecting crops from field diseases. The plant immune system is multifaceted and composed of many different proteins with broad functions. In the battle between the host and pathogens, plant gene expression and regulations play a central role in establishing an effective immune response.The aim of this work is to find out exactly how immune gene regulators, especially transcription factors (proteins that regulate gene expressions), work at the molecular level, how they are activated or repressed, and how they influence the amplitude of immune responses. Different pathogens use different strategies to attack the same host plants, so a major challenge is how to boost the plant immunity against all pathogens without compromise; with the correct combinations, and how to control their expression precisely. Understanding the changes to chromatin (histone protein with DNA molecules) that occur during the immune process is key to decode the genetic information of immune gene regulations.To address these important questions, I will study host proteins involved in the interaction between the model plant Arabidopsis and its pathogens. Working with a model plant offers many advantages over directly studying crop plants, the most important being the wealth of genetic and technological tools available (fully sequenced and annotated genome, thousands of mutants and worldwide data repositories) and the general ease of experimentation (small stature, fast growth, and convenient breeding techniques). The project will be undertaken at the Sainsbury Laboratory in Norwich [4], a world-leading research institute dedicated to working on plant-microbe interactions, and will involve collaborative work with laboratories in Canada. Knowledge gained from this project will advance our understanding of how plants defend themselves against pathogens and provide agricultural practices to improve crop yield.[1] 'Yes, we have no bananas' The Economist (1 March 2014); [2] 'Florida's orange groves are being wiped out by tree-killing bacteria' the Columbia Broadcasting System (CBS) News (26 October 2016); [3] 'Ash dieback 'could affect 75% of trees worst hit areas'' The Guardian (30 April 2014); [4] www.tsl.ac.uk.