Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

China

The famous cereal 'green revolution' of the 1960s/1970s increased crop yields, averted famine and fed a growing world population. Green Revolution Varieties (GRVs) of rice and wheat were the genetic foundation of the green revolution. GRVs carry mutant growth regulatory genes that confer dwarfism, and this dwarfism increases yield because it reduces loss due to 'lodging' (flattening of plants by wind and rain), hence causing the yield increases of the green revolution. However, the mutant growth regulatory genes also cause GRVs to be less efficient in assimilating the nitrogen (N) supplied to them in the form of fertilizer. As a result, N that is not assimilated by GRVs is dissipated into the wider environment, where it causes severe damage to terrestrial and aquatic ecosystems, together with atmospheric greenhouse-gas pollution that precipitates climate change. Because today's high-yielding crop varieties still depend upon the mutant dwarfing genes for their high yields, it is necessary to find ways of developing new crop varieties that retain the benefits of GRV dwarfism but that are more efficient in their use of N fertilizers (have improved N use efficiency, NUE). Here we propose to exploit the rapid genetics and molecular biology of the genetic model Arabidopsis to make discoveries that will enable future enhancement of GRV NUE. The GRV dwarfing genes cause accumulation of a class of growth inhibitory proteins called DELLAs, and DELLAs also accumulate in the dwarf Arabidopsis GRV mutant model gai. Accumulated DELLAs inhibit the action of another class of regulatory proteins, the PIFs (or Phytochrome Interacting Factors). Our recent preliminary evidence from studies of Arabidopsis suggest that the inhibitory effect of DELLAs on PIFs may explain the reduced NUE of GRVs, and it is this novel and exciting finding that we exploit in this proposal. We will therefore first further test our working hypothesis that interactions between DELLAs and PIFs affect the assimilation of N: that the DELLAs accumulated in GRVs and gai oppose PIF function, thus reducing N assimilation. If this hypothesis is correct, modulation of the DELLA-PIF relationship may provide a novel route towards improving GRV NUE. We have the following objectives: A. Obtain an in-depth understanding of PIF-regulation of Arabidopsis and rice N assimilation - essentially performing genetic tests of the role of PIFs in regulation of N metabolism and assimilation in Arabidopsis and rice. B. Determine how the DELLA-PIF interaction regulates the abundance of mRNA encoding nitrate reductase (NR), a key enzyme in N assimilation - this an exploration of how the DELLA-PIF interaction controls the expression of the gene encoding that enzyme. C. Determine if the DELLA-PIF interaction also directly affects the abundance and/or specific enzymatic activity of the NR enzyme itself. D. Determine if NUE can be increased despite retaining yield-enhancing dwarfism. This is important because it could lead to the development of crops which retain the high yields of current GRVs, but at reduced environmental cost. First, we will determine if increasing PIF activity might confer such benefits. However, because increasing the activity of PIFs themselves in GRVs might have additional unwanted consequences, we will additionally explore other routes (downstream of PIFs) to improving GRV NUE whilst retaining yield-enhancing dwarfism. Inherent in our strategy is initial translation of findings from Arabidopsis model to crop (rice), exploiting our long-standing combined expertise in DELLA biology, model-crop translations, and whole genome sequence analysis. Our long-term aim (future proposals) is to use the fundamental understanding gained here in the development of rice and wheat GRVs having enhanced NUE, thus enhancing global food security and reducing agricultural environmental degradation.

Exposure to poor air quality is the top environmental risk factor of premature mortality globally with an estimated 4 million premature deaths in 2015 from long-term exposure to current levels. By far the most damaging air pollutant to health is particulate matter (PM). The International Agency for Cancer Research has recently classified air pollution as a known carcinogen, with particle pollution being most closely associated with increased cancer rates. Chinese megacities, such as Beijing and Guangzhou, frequently exceed recommended exposure guidelines for particles less than 2.5 microns in diameter (PM2.5). According to official data, the annual mean concentrations of PM2.5 in 2016 in Beijing and Guangzhou were nearly 7 and 4 times higher than World Health Organisation guidelines. A study of 272 Chinese cities found that increases in PM2.5 could be linked to increases in mortality, chronic obstructive pulmonary disease, respiratory diseases, stroke, coronary heart diseases, hypertension and from cardiovascular disease. Therefore the population in Chinese megacities is subjected to damaging levels of particles over extended periods. One of the aims of the recent NERC/MRC funded Air Pollution and Human Health in a Chinese Megacity program was to investigate the sources of PM and develop strategies to reduce exposure to harmful levels of air pollution. Aerosol samples collected during two field deployments in Beijing were analyzed and unusually high levels of nitrophenolic compounds were observed. Nitrophenols can have a range of important atmospheric impacts. Nitro-aromatic compounds, and their atmospheric and biological reaction products, have detrimental effects on human and plant health. For instance, toxic effects in humans after dermal, oral, or respiratory exposure include gastrointestinal, neurological and reproductive disorders, cirrhosis of the liver, hepatitis, cataracts, respiratory and skin irritation, nephrotoxicity, and haematological defects. Some nitrophenols are phytotoxic and may be harmful to plants and aquatic life. The amounts of nitrophenols observed in Beijing were much higher than in previous studies in urban areas and the source of these compounds is unclear. This ambitious project will bring together expertise in chemical mechanism development (Rickard), simulation chamber experiments (Wang) and detailed aerosol composition measurements (Hamilton) to understand the sources and formation processes of nitrophenols and secondary organic aerosol from the atmospheric oxidation of aromatics and phenolic species, under conditions observed in the Beijing urban atmosphere. This project will address key uncertainties arising from the measurements of particle composition during haze events in Beijing and widen the results by applying the methodologies to a different Chinese megacity, Guangzhou. We will improve current representations of phenolic chemistry in the Master Chemical Mechanism (MCM), which is extensively used in a wide variety of air quality science and policy applications. This will be used to design simulation experiments at the Guangzhou Institute of Geochemistry to study the formation of nitrophenols under controlled conditions. We will measure the atmospheric levels of nitrophenols in Guangzhou in summer and winter and combine this with additional data from Beijing to determine the sources and factors that control nitrophenol concentrations. We will also initiate collaboration between the Chinese partner institute and the EUROCHAMP-2020 network, which aims to integrate the most advanced European atmospheric simulation chambers into a world-class infrastructure for research and innovation. Long lasting impact will be achieved through a knowledge exchange placement, where a member of staff from GIG will spend 12 weeks in York to receive training on the MCM and the protocols developed in Europe to model the background chemistry within simulation chambers.