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The number of invasive fungal pathogens has increased exponentially during the last century and some of them have caused devastating diseases on food crops and forest trees. Next generation sequencing techniques have significantly increased our ability to study nonmodel fungi. These techniques provide exciting new opportunities to study phytopathogen emergence and associated adaptive events. The proposed project will focus on the invasive oak powdery mildew species Erysiphe alphitoides and Erysiphe quercicola. Unlike the great majority of powdery mildew species which are highly specialized pathogens, E. alphitoides and E. quercicola are not only found on oaks but on a variety of other plant species. It has been hypothesized that both species were introduced from Asia into Europe by early Portuguese explorers, possibly with mango plants, and then realized a host jump to oak. Using the PacBio sequencing technique and double-digest restriction-site associate DNA sequencing, substantial genomic resources of Erysiphe spp. will be acquired to test specific scenarios of introduction and to focus on subsequent adaptation processes during invasion. Therefore, populations will be sampled on oak in Japan, on oak and mango in Spain and on oak in Europe on a south-western to north-eastern gradient. Analyses of genetic diversity, population structure and gene flow patterns between populations will shed light on the pathogen’s invasion history in Europe. Subsequent adaptation genomic analyses will focus on patterns of divergent selection that explain host shifts and host adaptation in Europe. In addition, over 200 historical Erysiphe herbarium specimens from 1875 until 1995 will be re-identified by ITS sequencing to date the exact time of arrival of the different species. A better understanding of oak powdery mildew invasion pathways and adaptation processes will yield fundamental knowledge on general patterns of biological invasions and will hopefully help conciliate problems associated with emerging diseases in the future.
I graduated in 2009 at the University of Zurich where I did a master thesis about the signaling pathway of a major powdery mildew resistance gene in wheat. In 2010 I changed to ETH Zurich and worked on my doctoral thesis about the reproduction system and population structure of the invasive and highly destructive ash dieback pathogen Hymenoscyphus fraxineus. After my PhD I carried on working with the same pathogen within the same lab but shifted the subject more to pathological and taxonomical aspects. From the beginning of 2017, I started a new adventure as an AgreenSkills postdoc at INRA Biogeco in Bordeaux, where I started working on the invasion history, population structure and genomics of oak powdery mildews in Europe. This postdoc ended earlier than previewed because I obtained a permanent position as a scientific associate at the Swiss Federal Institute WSL. Since the beginning of 2018, I am responsible for the national datacenter SwissFungi which collects observation data on fungi and which works together with the federal office of the environment to establish e.g. the fungal red lists. My goal at this position is to empower research on conservation biological aspects of fungi.
Gross A, Beenken L, Dubach V, Queloz V, Tanaka K, Hashimoto A, Holdenrieder O, 2017. Pseudodidymella fagi and Petrakia deviata: Two closely related tree pathogens new to central Europe. Forest Pathol.47 (5):e12351-n/a. Doi:10.1111/efp.12351.
Landolt J, Gross A, Holdenrieder O, Pautasso M, 2016. Ash dieback due to Hymenoscyphus fraxineus: what can be learnt from evolutionary ecology? Plant Pathol 65 (7):1056-1070.
Wey T, Gross A, Schlegel M, Stroheker S, 2016. MAT - gene structure and mating behavior of Hymenoscyphus fraxineus and Hymenoscyphus albidus. Fungal Genet Biol 87:54-63.
Gross A, Han JG., 2015. Hymenoscyphus fraxineus and two new Hymenoscyphus species identified in Korea. Mycol. Progr. 14 (4):1-13.
Gross A, Holdenrieder O, 2015. Pathogenicity of Hymenoscyphus fraxineus and H. albidus towards Fraxinus mandshurica var. japonica. Forest Pathol 45 (2):172-174.
Gross A, Hosoya T, Queloz V, 2014. Population structure of the invasive forest pathogen Hymenoscyphus pseudoalbidus. Mol. Ecol. 23 (12):2943-2960.