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The fungal genus Plectosphaerella comprises species and strains with different lifestyles on plants, such as P. cucumerina, which has served as model for the characterization of Arabidopsis thaliana basal and nonhost resistance to necrotrophic fungi. We have sequenced, annotated, and compared the genomes and transcriptomes of three Plectosphaerella strains with different lifestyles on A. thaliana, namely, PcBMM, a natural pathogen of wild-type plants (Col-0), Pc2127, a nonpathogenic strain on Col-0 but pathogenic on the immunocompromised cyp79B2 cyp79B3 mutant, and P0831, which was isolated from a natural population of A. thaliana and is shown here to be nonpathogenic and to grow epiphytically on Col-0 and cyp79B2 cyp79B3 plants. The genomes of these Plectosphaerella strains are very similar and do not differ in the number of genes with pathogenesis-related functions, with the exception of secreted carbohydrate-active enzymes (CAZymes), which are up to five times more abundant in the pathogenic strain PcBMM. Analysis of the fungal transcriptomes in inoculated Col-0 and cyp79B2 cyp79B3 plants at initial colonization stages confirm the key role of secreted CAZymes in the necrotrophic interaction, since PcBMM expresses more genes encoding secreted CAZymes than Pc2127 and P0831. We also show that P0831 epiphytic growth on A. thaliana involves the transcription of specific repertoires of fungal genes, which might be necessary for epiphytic growth adaptation. Overall, these results suggest that in-planta expression of specific sets of fungal genes at early stages of colonization determine the diverse lifestyles and pathogenicity of Plectosphaerella strains.

8 Pág. Centro de Biotecnología y Genómica de Plantas, Hg is a global concern given its adverse effects on human health, food security and the environment, and it requiring actions to identify major local Hg sources and to evaluate pollution. Our study provides the first assessment of Hg stock trends on the entire Majorca surface, identifying major Hg sources by studying the spatiotemporal soil Hg variation at two successive times (2006 and 2016-17). The Hg soil concentration ranged from 14 to 258 μg kg-1 (mean 52 μg kg-1). Higher concentrations (over 100 μg kg-1) were found in two areas: (i) close to the Alcudia coal-fired power plant; (ii) in the city of La Palma. During the 11-year, the total Hg stock in Majorcan soil increased from 432.96 tons to 493.18 tones (14% increase). Based on a block kriging analysis, soil Hg enrichment due to power plant emissions was clearly detectable on a local scale (i.e. a shorter distance than 18 km from the power plant). Nonetheless, a significant island-wide Hg increase due to diffuse pollution was reported. This result could be extrapolated to other popular tourist destinations in the Mediterranean islands where tourism has increased in recent decades In short, more than 60 tons of Hg have accumulated on Majorca island in 11 years., We greatly appreciate the financial assistance provided by Spanish Ministry of Science and Innovation (Project CGL2013-43675-P) and CAM (Project AGRISOST-CM S2018/BAA-4330).