Molecular interactions between genetics and plant pathology: a fungal point of view
Once upon a time, some geneticists began studying fungal plant pathogens as intriguing subjects for their research. Flor examined the segregation of rust virulence on resistant flax cultivars. Eureka! He discovered that a single gene was involved, allowing him to formulate the simple hypothesis known as the gene-for-gene relationship. This concept is still in use today, despite our current understanding that avirulence genes can interact with each other as enhancers or suppressors. In those early days, fungal genetics primarily relied on classical genetics (segregation in crosses) which was challenging due to asexual nature of many plant pathogenic fungi. This challenge was overcome through worldwide collaborations to identify fertile isolates. Successful crosses were eventually achieved, paving the way for map-based cloning of some of the first avirulence genes. With the advent of international sequencing projects in 2000, fungal genomes were decoded, opening new avenues for fungal molecular genetics and evolutionary studies. These approaches are now facilitated by the ease of obtaining complete genome sequences and transcriptomes. This accumulation of genetic and genomic data has become quite exhaustive, enabling the study of more complex biological processes involving multiple genes, and their interactions, the grail of any geneticist.