O papel da epigenética na memória somática do stress abiótico em batateira

The main objective of PoPRIMERS is to find a simple but ambitious system to enhance potato resilience to heat stress. Temperature cannot be controlled during potato culture in field conditions contrary to drought which can be diminished with irrigation and to biotic stress (pathogens/insects) which can be attenuated by the use of pesticides. Therefore, it is important to find a way to increase the natural resilience of potato to heat stress. We intend to expose potato plants to a first mild stress in in vitro plants and test the plant's response and tuber yield after a second stress in soil conditions, mimicking the industrial process of tuber production. Potato resilience improvement to climate change is a priority to the potato sector worldwide, especially because potato is regarded as a highly promising crop for alleviating global hunger and poverty. Although potato thermotolerance can be triggered by priming conditions, this has only been tested in soil in a controlled greenhouse and for a very short period (48 h). One of our goals is to assess how long potato plants can retain priming memory by testing three somatic generations. This proposal will bring novelty by specifically addressing if there is a long-lasting heat stress memory induced by priming and if it requires DNA methylation. The specific aims are: (1) Identify heat stress somatic memory by inducing priming in vitro and further stress challenge in soil conditions over three somatic generations (2) Identify candidate heat stress memory genes (3) Characterize DNA methylation variations in heat stress somatic memory (4) Identify heat memory genes or TEs affected by DNA methylation (5) Unveil the role of DNA methylation in the tuber phellogen and phellem stress response; (6) Explore the potential impact of maintenance and de novo DNA methylation in priming response in the phellogen and phellem (7) Validate the potential priming in field conditions These specific objectives will be pursued using a multidisciplinary approach by combining plant physiology, reverse (epi)genetics, transcriptomics, and epigenomics (general project scheme in annex 2). This methodology will complement the transcriptomics approaches used so far, filling a gap, and if successful, will generate pioneer knowledge on epigenetic regulation of potato priming and contribute to increasing our knowledge of the biology of such socially and economically relevant plants. Moreover, comprehending the molecular mechanisms at the genetic and epigenetic level will be essential to develop other and novel strategies that mitigate the impact of abiotic stress and set the ground for finding epitypes, i.e., group of individuals with the same genome, but with different epigenomes resulting in different phenotypes [32], adapted to climate change. As an ultimate goal, if a long-term somatic memory is validated in field conditions, the potato producers could adapt/test in vitro priming conditions to other potato genotypes, depending on their specific challenges.