Fire-adapted seed traits in Cerrado species

NERC-FAPESP Seedcorn Fund Collaboration Project "Fire-adapted seed traits in Cerrado species" between RHUL (UK) and UNESP (Brazil)

Fire is a global phenomenon which together with climate shapes the vegetation of natural and agricultural land. Our interaction with fire is characterised by both positive and negative aspects for mankind. Humans have long used fire including for landscape and weed management, and as tool to improve crop growth on arable land. Controlled fire is necessary to preserve the health and stimulate rejuvenation of wildland ecosystems such as the Brazilian Cerrado, the Mediterranean, as well as UK peatland and moorland. In these fire-prone regions plant regeneration is achieved to a large extent from soil-stored plant seeds. Depending on the species, environment, season and seed properties, the germination of the soil-stored seeds may be stimulated by compounds derived from the smoke or by the fire-generated heat-shock. The aim of the project is to comparatively investigate seeds from species adapted to fire-prone regions to identify novel mechanisms underpinning fire-generated heat-shock and smoke as germination cues. The derived mechanisms will be tested as tools for weed management and crop seed enhancement.

Treatment with smoke and various smoke-derived compounds can stimulate the germination of certain weed seeds. This can be used as a weed management tool to deprive the soil from weeds prior to crop seed sowing. We however do not know why this does not work with all weed species, at all ambient conditions (temperature, seasons), and what seed structures and seed coat properties determine the effectiveness of the treatment. Smoke, various smoke-derived compounds, as well as heat-shock treatment can also improve the seed quality and performance of seedling establishment of certain vegetable crops. Again, we do not know what seed structures, seed coat properties and genes are responsible for these effects and why it only works with certain crop species. To advance our knowledge in this topic the leading seed science lab of Royal Holloway University of London (RHUK, United Kingdom) will collaborate with experts for fire vegetation management and Brazilian Cerrado species properties of Sao Paulo State University (UNESP, Brazil). The FAPESP-NERC programme is especially suited to support this collaboration based on the agreement of the two funding agencies.

In the project we will investigate seeds of different fire-adapted species to identify novel mechanisms controlling how fire-derived smoke and heat-shock affect their germination, storability, and seedling establishment. This work will be conducted using methods from different science and engineering fields (including molecular biology, microscopy/imaging, biomechanical engineering, physiology) through interdisciplinary collaboration in a comparative approach with many fire-adapted species. This approach will for example identify certain seed coat properties or certain genes associated with the adaptation to fire-derived cues. Seeds of weed and crop species with similar properties/genes will then be used to test if the identified novel mechanism has potential for weed control or improving crop seed quality. The consortium has solid fire vegetation management and agri-technological expertise in these applications to provide solutions for this global challenge in climate change, healthy environment and food security.

Beyond academic beneficiaries, professionals in man-made fire and wildfire, vegetation and land management and policy making are beneficiaries from our research. Both countries, Brazil and the UK have a long-established wildfire research and management experience with the Brazilian Cerrado and UK peatland and moorland as major fire-prone national ecosystems. There is a need for a consistent fire policy for Cerrado conservation in Brazil, and the non-existing national wildfire agency or strategy in England as well as the role of fire in UK peatland and moorland management are a matter of ongoing discussions. Wildfires have shaped the fire-adapted ecosystems, but the vegetation and land management consequences of the intense 2018 fires are beyond the natural fire regimes (intensity and severity). A Royal Society workshop on the interaction of fire and mankind concluded that wildfire research should be integrated across disciplinary and national academic frameworks so that research and policy can tackle 21st century fire problems. Brazil's EMBRAPA-Cenargen, which focuses on conservation and management of genetic resources of the Cerrado.

Beyond ecosystem services for natural landscapes, prescribed burning has been used for managing arable land. Farmers, the agricultural and horticultural sector, the seed technology, crop breeding and weed management industry are key beneficiaries of our Brazil-UK research project into "fire: heat-shock and smoke". Smoke water is used in to enhance germination and trigger a flush emergence in arable weed management strategies; Prof Leubner's interview "Smoking out blackgrass seeds" at the SEB Annual Meeting 2016 in Brighton is an example for this (Science Daily https://www.sciencedaily.com/releases/2016/07/160706091510.htm). The seed germination of vegetable crops can be improved with smoke water priming treatment and heat-shock of crop seeds is a technology to improve the storage resilience of commercial seed. Seed industry, including major collaboration partners of RHUL's Seed Science Group (KWS Seed SE, Syngenta, Tozer Seeds, Elsoms Seeds, Croda/Incotec, Royal Horticultural Society - RHS) are therefore key stakeholders for both aspects of our fire research: heat-shock and smoke. Brazil is a world leader in applied seed technology and many seed companies have a research base in the country. The global seed market has a value of $50billion (2012) and of this the EU ranks 3rd (20%) and Brazil 4th (6%). Seed industry in Brazil and the UK is among the beneficiaries of our research collaboration.

For the impact in potential applied follow-up projects improving Cerrado seed quality for restoration projects is also a very timely topic and crucial need. Our experience seed science and technology applied to this challenge together with the smoke water and heatshock results from the Seedcorn project will certainly be important to achieve this in applied follow-up projects. Restoration of Cerrado is of great challenge, mostly because Cerrado's resilience is being lost due to changes in land use. The use of novel direct seeding with seed technology refined native seed therefore holds great potential for preserving the Cerrado biodiversity.

Finally, there are direct and indirect socioeconomic and health impacts of fire and smoke on people and society. Fire can destroy livelihoods and smoke pollution from different sources is a public health problem. This is also a focus RHUL's Wildfire Research Hub (Leverhulme Trust) which is into fire, climate change, people & habitat protection in several global regions one of which is the Brazilian Cerrado. Their fire social-ecological and policy-related research is very different to our project into the mechanisms of fire-adapted seed traits, but there will be opportunities for synergism with fire-related impact activities and networking, especially if it is associated with the Brazilian Cerrado. The general public is also among our stakeholders.