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.

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.

Rice is the principal crop in China, comprising 36.9% of the world rice crop. Estimates suggest yield increases of 50% are needed by 2050 to ensure food security. The areas used to cultivate rice and timings of planting are driven by climatic conditions. Rice is cultivated across China; nevertheless the frequency of cropping and the areas where high yields can be realised are limited by temperature. Global climate warming negatively affects mean rice yield, but also variance in yield, leading to increased frequencies of low yields. Additionally, increased mean temperature negatively impacts on the length of vegetative growth and reproductive growth periods. Flower development is critical for plant breeding and seed production, and thus directly impacts on yield. Pollen formation is highly sensitive to temperature stress; high temperature stress during flowering therefore poses a serious threat to current and long-term crop yields. This is particularly the case since flowering and seed set typically occur during a single, transient stage of plant development, which unlike vegetative associated-stress, cannot be rescued if conditions subsequently improve. High temperatures reduce the number of flowering branches and therefore the number of flowers per plant, however abnormalities in pollen formation result in male sterility and thus failure of seed set. There is thus the potential for devastating yield losses if resilience to reproductive temperature stress is not developed, particularly given the rises in global temperature and the increased volatility of climatic conditions. Nevertheless there is considerable genetic variability in tolerance to high temperature between species and genotypes. Understanding how plants cope with heat stress during reproductive development offers the potential to identify genetic traits that can be manipulated and utilised to improve temperature tolerance in crops. This project will address these issues by developing germplasm with enhanced resilience to temperature stress. The programme will also provide detailed understanding of the molecular and cytological changes occurring during reproduction under heat stress, and the mechanisms conferring resilience to high temperatures. Developing such resilience will allow expansion of the areas used for rice cultivation, but also the timing and frequency of rice planting. This will lead to higher rice yields, but also to more resilient yields regardless of environmental fluctuations and global climate changes. Environmentally controlled male fertility also has major applications for developing materials for hybrid breeding. Knowledge and germplasm obtained from this project will therefore have direct application in hybrid rice breeding programmes for increased yield. The programme will use Natural Variation to identify loci conferring resistance to reproductive heat stress for breeding programmes for crop improvement, and to characterise these traits. Two populations will be screened, i) a "Diversity Panel" comprising 800 global representative rice lines derived from diverse locations and environments, identified from the 3000 Genome Rice Project and, ii) a population of indica/japonica chromosomal segment substitution lines, which has known diversity in fertility responses to environment. This material will be phenotyped in field and glasshouse conditions for altered fertility and floral architecture as a consequence of heat stress. GWAS and Introgression marker analysis will be used to identify the loci responsible. Molecular tools and transgenic lines will be used to dissect the mechanisms behind these traits. This will be supported by detailed microscopic and expression analysis. In addition transcriptomic approaches will be used to characterise the molecular changes occurring during plant reproduction under heat stress, specific emphasis will be paid to tapetum function and Programmed Cell Death (PCD) during pollen development.

World food demand is predicted to double by 2050. Meeting this demand is a major global challenge, and requires increased crop yields at minimal environmental cost. Present-day high-yielding 'green revolution crop varieties' (GRVs) are inefficient in their use of nitrogen (N) fertiliser, an inefficiency that is costly to the farmer and damaging to the environment. The world needs new crops that are both higher yielding and have increased N use efficiency (NUE). Our project fuses distinct UK/China expertise to improve rice NUE. It retains the outstanding features of current rice GRVs, and transforms them into Super-Rice varieties that are high yielding and have enhanced NUE. Using a pioneering approach combining the discovery of natural genetic variants with marker-assisted breeding and 'genome editing', we will create Super-Rice that will be high-yielding when grown with reduced N fertiliser inputs. First, WPs1-3 exploit a variety of genetic, genomic and bioinformatics techniques to discover individual genetic variants that increase the NUE of rice GRVs. WP1 discovers the molecular identities of variant genes increasing NUE in the field. WP2 focusses on variants of the developmental regulatory genes that play overarching roles in controlling the growth and metabolism of plants. There is important precedent for exploiting such regulatory variation, because the initial GRVs themselves were created by use of such variants. WP3 focusses on the discovery of variants increasing the activity of the transporters that enable rice to extract N from the soil. However, the variants discovered in WPs1-3 may come from wild or other strains of rice that are not themselves GRVs. WPs1-3 therefore importantly use the new technique of genome-editing to specifically determine if these new variants increase NUE in GRV genetic backgrounds. Genome-editing enables precise alteration of genome sequence, thus enabling us to edit specific GRV gene sequences (change them into the newly discovered variant form). The yield of these genome-edited GRVs will then be measured in low-N soils, thus telling us if the newly discovered variant can indeed increase the NUE of the GRV. Next, WP4 further exploits the ability of genome editing to simultaneously edit more than one genomic location. This enables the combined ('stacked') introduction of multiple variants into one GRV. It is possible that variant combinations will generate NUE increases that are at least additive (a simple sum of individual variant effects) and that may be synergistic (increases that are greater than the simple sum effects of individual variants). Thus, in WP4, we will combine ('stack') multiple selected variants into Super-Rice genotypes, and then determine the yields of these Super-Rice genotypes in low-N soils. Our genome-edited Super-Rice will not contain any 'foreign' transgenes, and may therefore more readily receive regulatory approval for agricultural use than will transgenic 'GM' varieties. However, because full adoption of Super-Rice requires general public acceptance, we will also pioneer the use of genome-edited Super-Rice to enhance the efficiency, focus and speed of conventional marker-assisted breeding of Super-Rice. Genome-edited Super-Rice will guide plant breeders in the development of (non-genome-edited) Super-Rice that will be bred using natural rice variants and that will be publicly acceptable because it is neither GM nor genome-edited. The promotion of bilateral UK-China rice research relationships is another major objective of our proposal. We build upon and sustain pre-existing partnerships (XF and NPH; XF and QQ), and derive added value from a new one (NPH and QQ). In summary, we propose a transnational UK-China partnership that will breed publicly acceptable enhanced-NUE Super-Rice that will enhance the sustainability of Chinese and world agriculture and help feed the world in the years leading up to 2050 and beyond.