AUTHOR=Frézal Lise , Jacqua Guy , Neema Claire 

TITLE=Adaptation of a Fungal Pathogen to Host Quantitative Resistance

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01554

DOI=10.3389/fpls.2018.01554

ISSN=1664-462X

ABSTRACT=<p>Impact of host quantitative resistance on pathogen evolution is still poorly documented. In our study, we characterized the adaptation of the pathogenic fungus <italic>Colletotrichum gloeosporioides</italic>, to the quantitative resistance of its host, the water yam (<italic>Dioscorea alata</italic>). Genetic and pathogenic diversities of <italic>C. gloeosporioides</italic> populations were specified at the field scale. We used nuclear markers to describe fungal population structuring within and between six fields of three cultivars differently susceptible to the fungus. Strain aggressiveness was then quantified in the laboratory through cross-inoculation tests. The high level of genetic diversity and significant linkage disequilibrium revealed a significant influence of clonal reproduction in the <italic>C. gloeosporioides</italic> evolution. The recorded fungal migration between fields was weak (evidence for a dispersion mode via tubers rather than splashing dispersal), which provides the first molecular evidence for limited <italic>C. gloeosporioides</italic> migration via yam tuber exchanges. <italic>C. gloeosporioides’s</italic> populations are adapted to their host resistance. The aggressiveness of the fungal clones seems to have evolved toward an accumulation of components specific to each host cultivar. Despite the remaining marks of adaptation to the former widely cultivated host, adaptation to current cultivars was clearly depicted.</p>