Genomics-assisted exploration of global diversity and evolutionary mechanisms in the host generalist fungus Sclerotinia sclerotiorum

Thursday, July 17, 2025

10:30 - 10:50

Location: Room M+N

Presenting Author(s)

MD

Mark Charles Derbyshire, PhD (he/him/his)

Centre for Crop and Disease Management
Perth, WA, AUSTRALIA

Author(s)

TN

Toby Newman

Curtin University
Perth, Western Australia, Australia
YK

Yuphin Khentry

Curtin University
Perth, Western Australia, Australia
PM

Pippa J. Michael

Centre for Crop and Disease Management, Curtin University, Australia
SB

Sarita J. Bennett

Centre for Crop and Disease Management, Curtin University, Australia
AR

Ashmita Rijal Lamichhane

Centre for Crop and Disease Management, Curtin University, Australia
CG

Carolyn Graham-Taylor

Centre for Crop and Disease Management, Curtin University, Australia
SC

Subhash Chander

Department of Genetics and Plant Breeding, Oilseeds Section, CCS Haryana Agricultural University, India
CC

Claudia Camplone

Department of Agricultural, Food and Environmental Sciences, University of Perugia, Italy
SV

Simone Vicini

Department of Agricultural, Food and Environmental Sciences, University of Perugia, Italy
LE

Laura Esquivel Garcia

Plant Science, Mcgill University, Canada
CC

Cathy Coutu

Agriculture and Agri-Food Canada, Canada
DH

Dwayne Hegedus

Agriculture and Agri-Food Canada, Canada
JC

John Clarkson

Warwick Crop Centre, School of Life Sciences, University of Warwick, UK
KL

Kurt Lindbeck

Department of Primary Industries, New South Wales, Australia
LK

Lars Kamphuis

Curtin University
Perth, Western Australia, Australia

Adaptation of pathogens to different agricultural production systems underpins maintenance of existing crop diseases and emergence of new ones. Host generalists are attractive models for understanding evolutionary mechanisms that sustain pathogenicity on divergent crop species. Our research is focused on the fungus Sclerotinia sclerotiorum, which infects hundreds of plant species in over 75 families, persistently threatening crop production worldwide. Using 25 high quality long read and 190 short read genomes from S. sclerotiorum isolates collected from four continents, we find evidence for both long-term maintenance of clones and pervasive sexual outcrossing to create recombinant pathogen lineages. We also find that recombination rate is associated with the level of genomic structural variation independently of transposon richness. A possible mechanism for this association is erroneous double-strand break repair during meiosis, which we speculate contributes to genomic structural diversity in gene-rich regions. Though gene content was highly stable between strains, genome-wide association mapping suggested that structural variants had a greater average impact than other variants on many life history traits. Overall, our data suggest that transposition and recombination are important drivers of structural variation in global populations of S. sclerotiorum and that structural variation may be an important component of adaptive flexibility, despite its limited impact on gene content.