Unravelling the responses of non-model tree species to the environment: the case of Nothofagus pumilio a key species of the subantarctic forests

ESTRAVIS-BARCALA, M.; CAGNACCI, J; GAISCHUK, S; GONZALEZ-POLO, M; MARTINEZ-MEIER, A; MOYANO, T; CAVIA, R; HUA, W; WEIGEL, D; LIA, V; GUTIÉRREZ, RA; BELLORA, N; ARANA, MV

Congreso; XXXIV Reunión de la Sociedad Argentina de Fisiología Vegetal; 2023

Forests cover about 41 million km2 of the surface of the planet, and by sequestering large amounts of carbon they comprise a key element in countering the effects of increased CO2 production, such as global climate change. Despite this, predicted changes in climate are expected to have major impacts in trees. Revealing the physiological and molecular bases of their responses to the environment is therefore crucial for the development of conservation strategies and for breeding stress-resistant genotypes. Nothofagus pumilio is one of the tree species with the larger distribution area in Patagonia. This species ranges in elevation from 0 to 2000 meters above sea level in high latitudinal zones (55°S). However, north of 41°S, it occurs only in the sub-alpine zone –the coldest environments-, suggesting that it lacks adaptation to heat. In this talk I will show the way in which we use genomic tools in combination with laboratory and field experiments to explore the molecular bases of abiotic stress response in N. pumilio. We mainly focused on stress by high temperatures given that this factor resulted a major driver of seedling mortality in the forest. We generated a draft genome that nowadays condenses the analysis of differential expression experiments, genotype-phenotype associations and functional studies. We identified a wide spectrum of heat-responsive transcripts, including 59 transcription factors, alongside spliceosome machinery and hormone pathways. Both in field and laboratory experiments photosynthesis is apparently affected by stress. Preliminary association studies in seedling growing in natural environments identified nucleotide polymorphisms related to the phenotypic variation in photosynthetic traits, with the corresponding genomic regions encompassing genes related to development and stress response. Overall our work provides the first clues in the stress response of N. pumilio, and provides information of potential use in biotechnological programs.