Image Credit: Pascal Frey, INRAE, Nancy
Image Credit: Pascal Frey, INRAE, Nancy
Sphaerulina populi (Auersw.) J. Schröt. (Fungi, Ascomycota, Dothideomycetes, Capnodiales) is a pathogen that causes leaf spots on poplars. It has been reported in Eurasia. It causes circular lesions on leaves with dark brown or yellow margins, sometimes converging into large, irregular blotches with dark margins and tan centres, with small, black fruiting bodies at the centre. If infected early in the growing season, trees can suffer premature defoliation and terminal dieback. This fungus is closely related to Mycosphaerella populorum (Septoria musiva SO2202), a North American fungal pathogen that can cause leaf spots on poplars but also stem and branch cankers that can be lethal. Attacks by pathogens represent one of the most important threats to the sustainable growth of bioenergy trees in plantations. Outbreak prevention depends largely on a better understanding of how pathogens infect trees so that resistance can be developed and on early detection, monitoring and surveillance to prevent spread. Since pathogens of poplars and pines tend to track their hosts worldwide, we must do a better job at detection and surveillance. This can be challenging since pathogens can remain dormant or have endophytic stages in the host tissues. The genome sequencing of Sphaerulina populi is part of a larger effort, the Pathobiome database for bioenergy trees project, that aims at sequencing the genomes of multiple pathogens that share the same host trees in order to identify common and unique genomic signatures. By sequencing and comparing the genomes of the most important pathogens of poplars and pines, we plan to create a database that will be used to develop tools for the detection, monitoring, surveillance and rapid response of pathogens in these economically and ecologically important trees.
