Sequencing the genome of Marssonina brunnea reveals fungus-poplar co-evolution

Abstract

BackgroundThe fungus Marssonina brunnea is a causal pathogen of Marssonina leaf spot that devastates poplar plantations by defoliating susceptible trees before normal fall leaf drop.ResultsWe sequence the genome of M. brunnea with a size of 52 Mb assembled into 89 scaffolds, representing the first sequenced Dermateaceae genome. By inoculating this fungus onto a poplar hybrid clone, we investigate how M. brunnea interacts and co-evolves with its host to colonize poplar leaves. While a handful of virulence genes in M. brunnea, mostly from the LysM family, are detected to up-regulate during infection, the poplar down-regulates its resistance genes, such as nucleotide binding site domains and leucine rich repeats, in response to infection. From 10,027 predicted proteins of M. brunnea in a comparison with those from poplar, we identify four poplar transferases that stimulate the host to resist M. brunnea. These transferas-encoding genes may have driven the co-evolution of M. brunnea and Populus during the process of infection and anti-infection.ConclusionsOur results from the draft sequence of the M. brunnea genome provide evidence for genome-genome interactions that play an important role in poplar-pathogen co-evolution. This knowledge could help to design effective strategies for controlling Marssonina leaf spot in poplar.

Genomewide identification and development of microsatellite markers for Marssonina brunnea and their applications in two populations

“…This pathogen infects poplar leaves via the conidia or ascospores in primary infection and extend throughout the season with the conidia (Ostry, ). As previously reported, the sexual state of M. brunnea was not found in China and New Zealand, and genomic analysis showed that this pathogen might lack the capacity to perform sexual reproduction in China (He & Yang, ; Han, Li, & Huang, ; Zhu et al., ). M. brunnea infects various poplar species (Han, Yin, Li, Huang, & Wu, ; Spiers, ) and has often caused outbreaks in various countries in Europe (Newcombe & Callan, ; Spiers, ).…”

“…Marssonina leaf spot disease of poplar (MLDP) is a major disease affecting poplar trees (Beare, Archer, & Bell, ; He & Yang, ). MLDP generally causes black spots on the surface of the leaves and lesions on the petioles, resulting in premature defoliation and a significant reduction in photosynthesis (Spiers, ; Zhu et al., ). Furthermore, MLDP outbreaks can lead to tree death, which causes significant losses to the poplar industry, with a 30% annual decrease in average wood production having been recorded (Erickson, Stanosz, & Kruger, ; Wu et al., ).…”

Comparative genomics to explore phylogenetic relationship, cryptic sexual potential and host specificity of Rhynchosporium species on grasses

“…The total coverage of repetitive sequences is relatively high as compared to other fungi reaching 31% in R. commune , but lower than in the close relative Marssonina brunnea f.sp. ‘multigermtubi’ (see below; 42% [33]).…”

“…The closest relative of Rhynchosporium spp., the poplar pathogen M. brunnea f.sp. ‘multigermtubi’ [33], belongs to the Dermataceae , a family of one of the most diverse ascomycete orders, the Helotiales . This confirms a previous ITS-based phylogenetic analysis, which located R. commune and R. orthosporum between the Dermataceae species Tapesia yallundae (syn.…”

“…In addition, the bacterial PKS clade contains two subclades of fungal PKS. This phylogeny was first reconstructed based on the KS domain sequences from 86 ascomycete PKS (including eight from M. brunnea [33]), ten bacterial PKS and two animal fatty acid synthetases. Subsequently, it was complemented with the KS domain sequences of the 18 Rhynchosporium PKS (Fig.…”