Plant-infecting fungi are a major burden on the world’s food supply. One of the world’s best-known agricultural pests is the fungus Sclerotinia sclerotiorum. This fungus can infect hundreds of different plant species, in contrast to the single-host infection cycles of most other agriculturally significant plant pathogens.
The hosts of S. sclerotiorum include many of the world’s most important crops, such as soybean, oilseed rape, sunflower, chickpea and lettuce; in fact, all broad leaved (‘dicotyledonous’) plants seem to be susceptible to infection by this fungus. Thankfully however, cereal crops such as wheat, barley, oat and rye are not.
The large number of crop species infected by S. sclerotiorum makes it a major threat to global agricultural production. Thus, for several decades, S. sclerotiorum has naturally been the focus of many molecular scientists around the world. This is helped by the fact that S. sclerotiorum also infects thale cress and tobacco, two important experimental plant species that are well-suited to molecular research.
In 2005, a pathogen profile summarising research on S. sclerotiorum was published in Molecular Plant Pathology. Since then, a wealth of new research has expanded our understanding of the biology of this important pathogen.
For instance, we now know much more about the way S. sclerotiorum modifies molecular pathways in the plant to trigger ‘programmed cell death’. Essentially, S. sclerotiorum sends molecules into the plant that tell its cells to kill themselves. The dead plant cells provide the perfect nutrient source for S. sclerotiorum to grow and reproduce.
We also know that some plants tend to be more resistant to S. sclerotiorum than others of the same species, and that this resistance is controlled by hundreds of DNA sequence differences impacting hundreds of genes. It is the cumulative effect of these differences that influences the absolute level of resistance to S. sclerotiorum in plants.
However, despite this knowledge of the ‘genetic architecture’ of S. sclertorioum resistance, we still know very little about the precise functions of the genes involved. Only very recently have researchers been able to scratch the surface of this complex phenomenon. Research in this area has the potential to identify key targets for managing S. sclerotiorum through plant breeding or biotechnology.
This pathogen profile describes all major insights into the biology of S. sclerotiorum and its hosts gained in the last 20 years. In doing so, it identifies several key research questions and emerging areas of research that will be important in the future.
Mark C. Derbyshire, Toby E. Newman, Yuphin Khentry and Akeem Owolabi published this pathogen profile in Molecular Plant Pathology:
TITLE IMAGE: Typical Sclerotinia sclerotiorum symptoms on Canola. All images used with permission of the author.
