Abstract
Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that infects upwards of 400 plant species, including several economically important crops. The molecular processes that underpin broad host range necrotrophy are not fully understood. This study used RNA sequencing to assess whether S. sclerotiorum genes are differentially expressed in response to infection of the two different host crops canola (Brassica napus) and lupin (Lupinus angustifolius). A total of 10,864 of the 11,130 genes in the S. sclerotiorum genome were expressed. Of these, 628 were upregulated in planta relative to in vitro on at least one host, suggesting involvement in the broader infection process. Among these genes were predicted carbohydrate-active enzymes (CAZYmes) and secondary metabolites. A considerably smaller group of 53 genes were differentially expressed between the two plant hosts. Of these host-specific genes, only six were either CAZymes, secondary metabolites or putative effectors. The remaining genes represented a diverse range of functional categories, including several associated with the metabolism and efflux of xenobiotic compounds, such as cytochrome P450s, metal-beta-lactamases, tannases and major facilitator superfamily transporters. These results suggest that S. sclerotiorum may regulate the expression of detoxification-related genes in response to phytotoxins produced by the different host species. To date, this is the first comparative whole transcriptome analysis of S. sclerotiorum during infection of different hosts.
Highlights
Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that infects upwards of 400 plant species, including several economically important crops
Do these pathogens utilise the same infection strategy on different host species, or are they able to adapt to their environments? In the latter case, what mechanisms facilitate this flexibility? Though a considerable body of research has examined the determinants of host specificity in biotrophs and specialist necrotrophs[18,19], these biological questions have not been thoroughly addressed in a broad host range pathogen such as S. sclerotiorum
We can only confidently state that two candidate genes have strong evidence for up-regulation on B. napus relative to L. angustifolius. Necrotrophic phytopathogens such as S. sclerotiorum are known to utilise a variety of pathogenicity factors to facilitate infection, including carbohydrate-active enzymes (CAZymes), proteinaceous effectors and secondary metabolites[7,20,30]
Summary
Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that infects upwards of 400 plant species, including several economically important crops. The remaining genes represented a diverse range of functional categories, including several associated with the metabolism and efflux of xenobiotic compounds, such as cytochrome P450s, metal-beta-lactamases, tannases and major facilitator superfamily transporters These results suggest that S. sclerotiorum may regulate the expression of detoxification-related genes in response to phytotoxins produced by the different host species. Despite the economic constraints to crop production caused by S. sclerotiorum and other broad host-range necrotrophs as crop pathogens, the infection strategies of these species are far from fully elucidated[16]. Their ability to infect a diverse range of plant species is an intriguing area of research[17]. In the case of host generalists, the opposite perspective of “host generality” and its mechanisms may be intriguing
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
