Transcriptomic Analysis of Calonectria pseudoreteaudii during Various Stages of Eucalyptus Infection

Abstract

Eucalyptus leaf blight caused by Calonectria spp. is a serious disease in Eucalyptus seedling and plantations. However, the molecular mechanisms of the infection process and pathogenesis of Calonectria to Eucalyptus is not well-studied. In this study, we analyzed the transcriptomes of C. pseudoreteaudii at three stages of Eucalyptus leaf infection, and in mycelium grown in potato dextrose broth using Illumina RNA-Seq technology. We identified 161 differentially expressed genes between C. pseudoreteaudii from leaf and mycelium grown in potato dextrose broth. GO and KEGG enrichment analyses of these genes suggested that they were mainly involved in oxidoreductase activity, hydrolase activity, and transmembrane transporter activity. Most of the differentially expressed genes at the early infection stage were upregulated. These upregulated genes were mainly involved in cell wall hydrolysis and toxin synthesis, suggesting a role for toxin and cell wall hydrolases in the establishment of Calonectria leaf blight. Genes related to detoxification of phytoalexins were continually upregulated during infection. The candidate effectors and putative pathogenicity determinants identified in this study will help in the functional analysis of C. pseudoreteaudii virulence and pathogenicity.

Whole genome and transcriptome analysis reveal adaptive strategies and pathogenesis of Calonectria pseudoreteaudii to Eucalyptus

“…This could be attributed to the destruction of the cuticle in the medium. However, one cutinase gene (Ca_Cap05169) in C. pseudoreteaudii was up-regulated > 225-fold early in leaf infection [ 49 ].…”

“…6b ). Furthermore, one polygalacturonase gene (Ca_Cap14295) was up-regulated > 500-fold during the infection of Eucalyptus leaves [ 49 ]. These results imply that pectinase may play important role in the colonization of C. pseudoreteaudii on Eucalyptus leaves.…”

“…Two SSCPs (Cp_Cap02912, Cp_Cap04435) had homologs with the LysM domain-containing proteins, which may play roles in the sequestration of chitin oligosaccharides and in dampening host defense [ 53 ]. Five of these SSCPs were up-regulated during infection of Eucalyptus [ 49 ].…”

Boxwood blight: an ongoing threat to ornamental and native boxwood

“…The 55.0 Mb genome assembly of a North American isolate CBS 139707 (also known as cpsCT1) is assembled into just 27 scaffolds and is predicted to contain 16,304 genes (Crouch et al 2017 ). These genome sequences, along with assemblies for related fungi C. leucothoes , C. naviculata , and C. pseudoreteaudii , have already been employed for studies of mating-type, diagnostic marker development, and whole genome-scale sequence comparison of isolates from different hosts (Malapi-Wight et al 2014b , 2016a , b ; Ye et al 2017 ). Moving forward, these resources are likely to yield additional information about the genetic diversity of the boxwood blight pathogens.…”

Genome analysis of the ubiquitous boxwood pathogenPseudonectria foliicola

“…Although best known as soil-borne saprobes or weak plant pathogens, several species in this family are responsible for extensive economic losses due to damage incurred to crops or in natural ecosystems ( Halleen, Fourie & Crous, 2006 ; Malapi-Wight et al, 2016a ; Windels, 2000 ). The systematics and taxonomy of the Nectriaceae family has been extensively studied (e.g., Salgado-Salazar et al, 2014 ; Lombard et al, 2015 ) however, outside of the genus Fusarium , only a small number of fungal species in this family have genome resources publicly available, including Calonectria pseudonaviculata , C. pseudoteaudii , Dactylonectria macrodidyma and Ilyonectria destructans ( http://genome.jgi.doe.gov/Ilysp1/Ilysp1.home.html ; Malapi-Wight et al, 2015 ; Malapi-Wight et al, 2016b ; Ye et al, 2017 ). Whole genome resources are now commonly used to understand evolutionary characteristics of pathogenicity across fungi with different lifestyles ( Lo Presti et al, 2015 ) and could become useful for the characterization and biosecurity analysis of undescribed pathogens ( McTaggart et al, 2016 ).…”