Comparative genomic analysis revealed rapid differentiation in the pathogenicity-related gene repertoires betweenPyricularia oryzaeandPyricularia pennisetiisolated from aPennisetumgrass

Abstract

AbstractBackgroundsPyriculariais a multispecies complex that could infect and cause severe blast disease on diverse hosts, including rice, wheat and many other grasses. Although the genome size of this fungal complex is small [~40 Mbp forPyricularia oryzae(syn.Magnaporthe oryzae), and ~45 Mbp forP. grisea], the genome plasticity allows the fungus to jump and adapt to new hosts. Therefore, deciphering the genome basis of individual species could facilitate the evolutionary and genetic study of this fungus. However, except for theP. oryzaesubgroup, many other species isolated from diverse hosts, such as thePennisetumgrasses, remain largely uncovered genetically.ResultsHere, we report the genome sequence of a pyriform-shaped fungal strainP. pennisetiP1609 isolated from aPennisetumgrass (JUJUNCAO) using PacBio SMRT sequencing technology. We performed a phylogenomic analysis of 28 Magnaporthales species and 5 non-Magnaporthales species and addressed P1609 into aPyriculariasubclade that is distant fromP. oryzae. Comparative genomic analysis revealed that the pathogenicity-related gene repertoires were fairly different between P1609 and theP. oryzaestrain 70-15, including the cloned avirulence genes, other putative secreted proteins, as well as some other predictedPathogen-Host Interaction(PHI) genes. Genomic sequence comparison also identified many genomic rearrangements.ConclusionTaken together, our results suggested that the genomic sequence of theP. pennisetiP1609 could be a useful resource for the genetic study of thePennisetum-infectingPyriculariaspecies.