MimicWeed - Morphological, hormonal and genomic mechanisms of seed dormancy, germination and seedling vigour in weedy crop grass mimics

Sustainably enhancing agricultural food production as well as maintaining the natural environment around us, is of key economic/societal importance. The Food and Agricultural Organisation (FAO) has estimated that globally, up to 40% of crops are lost to pests and diseases (RM Spotlight information). Agricultural weeds account for one third of all crop yield loss and this loss would be far greater without herbicides. The continued effectiveness of herbicide technology is however threatened by the rapid advance of resistant weeds across most chemical classes and all major cropping regions. Collaborative work with industry into sustainable future weed management strategies must bridge approaches between "application" and "mechanisms/fundamental" to support generating a thriving bioeconomy whilst minimising adverse environmental impacts. Managing noxious annual weeds of the grass family is particularly challenging in cereal crops (wheat, rice, maize) where several evolved as weedy crop-grass-mimics. The aim of the MimicWeed project is to investigate if weedy non-crop relatives (barnyardgrass, blackgrass, crabgrass) and weedy crop relatives (weedy rice, originated from cultivated rice by de-domestication) employ the same or different mechanisms for their seed dormancy/germination, as well as their seedling growth and vigour in response to ambient temperature and climatic change. Our hypothesis is that de-domestication is an extension of crop evolution, and the comparison of weedy crop and non-crop relatives will therefore provide a diversity in mechanisms including for hormone sensitivities, dormancy and weediness traits. Application of this knowledge will support developing innovative approaches to manage noxious weeds in a more sustainable manner, and in addition will provide novel grass seed dormancy mechanisms which maybe used to reduce Preharvest Sprouting. The objectives are: (1) Morphological, biophysical and physiological characterisation of temperature and abscisic acid (ABA) responses in a biodiversity panel of weedy/cultivated rice (de-domestication pathway of weed evolution), and a collection of barnyardgrass, blackgrass, and crabgrass representing non-crop-relative grass weeds. A major focus are mechanisms of weed "seed" husks and fruit/seed coats properties for temperature responses, ABA sensitivity/leaching and dormancy. (2) Genome-wide association study (GWAS) for germination/dormancy, seedling growth, ABA sensitivity/leaching of the weedy/cultivated rice biodiversity panel. This will link genome sequences to phenotyping of seed and seedling-related traits (objective 1) (3) Comparative transcriptome and hormone analysis of secondary dormancy and early seedling growth of grass weeds. The induction of secondary dormancy in non-dormant seeds by appropriate abiotic stresses is a major weed adaption to climatic change; its molecular mechanisms are largely unknown. (4) To use ABA-mimicking chemicals as tools to investigate diversity in ABA sensitivities and mechanisms in crop-relative and non-crop relative grass weeds. The diversity of grass weed ABA receptor protein structures will be linked to the responses of ABA-mimicking chemicals. MimicWeed adresses UKRI/BBSRC strategic plans, challenges and priorities such as "Bioscience for sustainable agriculture and food", "Understanding the rules of life", and will train the next generation of weed scientists. Several of our impact activities are together with Syngenta and the services and policy advice provider ADAS. Classical paddy-field rice cropping systems are very resource intensive (water, labour) and carbon positive (methane). Environmental impact will be contributing to shifting from resource-heavy transplanted rice to more environmental-friendly direct-seeded rice (supports smallholders who are most impacted by climate change). Our vision is that MimicWeed will have socioeconomic impact on the sustainably enhancing agricultural food production by innovative weed management strategies.