Interspecific and host-related gene expression patterns in nematode-trapping fungi

Abstract

BackgroundNematode-trapping fungi are soil-living fungi that capture and kill nematodes using special hyphal structures called traps. They display a large diversity of trapping mechanisms and differ in their host preferences. To provide insights into the genetic basis for this variation, we compared the transcriptome expressed by three species of nematode-trapping fungi (Arthrobotrys oligospora, Monacrosporium cionopagum and Arthrobotrys dactyloides, which use adhesive nets, adhesive branches or constricting rings, respectively, to trap nematodes) during infection of two different plant-pathogenic nematode hosts (the root knot nematode Meloidogyne hapla and the sugar beet cyst nematode Heterodera schachtii).ResultsThe divergence in gene expression between the fungi was significantly larger than that related to the nematode species being infected. Transcripts predicted to encode secreted proteins and proteins with unknown function (orphans) were overrepresented among the highly expressed transcripts in all fungi. Genes that were highly expressed in all fungi encoded endopeptidases, such as subtilisins and aspartic proteases; cell-surface proteins containing the carbohydrate-binding domain WSC; stress response proteins; membrane transporters; transcription factors; and transcripts containing the Ricin-B lectin domain. Differentially expressed transcripts among the fungal species encoded various lectins, such as the fungal fruit-body lectin and the D-mannose binding lectin; transcription factors; cell-signaling components; proteins containing a WSC domain; and proteins containing a DUF3129 domain. A small set of transcripts were differentially expressed in infections of different host nematodes, including peptidases, WSC domain proteins, tyrosinases, and small secreted proteins with unknown function.ConclusionsThis is the first study on the variation of infection-related gene expression patterns in nematode-trapping fungi infecting different host species. A better understanding of these patterns will facilitate the improvements of these fungi in biological control programs, by providing molecular markers for screening programs and candidates for genetic manipulations of virulence and host preferences.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-968) contains supplementary material, which is available to authorized users.

Daily Indexes for Predation and Growth of Nematophagous Mushrooms Species of Hohenbuehelia (Pleurotaceae) on Panagrellus redividus

“…Andersson et al (2014), studied genes expression during infection process and proved chemical specificity between fungal-nematode interactions. However, nematode-trap fungi do not appear to have specificity to nematode host (Kerry, 2000).…”

Genomic Insights into the Adaptation to Parasitism in Nematode-Trapping Fungi and Transcriptomics during Infection of Caenorhabditis Briggsae and Plant-Parasitic Nematodes

“…A. oligospora has 52 genes containing the peptidase_S8 domain . However, only one transcript containing the peptidase_S8 domain was identified among the highly expressed transcripts in each library of A. oligospora infecting M. hapla and A. oligospora infecting H. schachtii (Andersson et al, 2014). The other cDNA libraries contained also only one transcript with the peptidase_S8 domain among the top 500 expressed genes.…”

“…The commonly expressed genes of A. dactyloides, A. oligospora and M. cionopagum during infection of Meloidogyn hapla and Heterodera schachtii were subtilisin (peptidase_S8), aspartyl proteases, CFEM (a fungal specific cysteine-rich domain that is found in some proteins with proposed roles in fungal pathogenesis) (Kulkarni et al, 2003), and the carbohydrate-binding WSC domain 2014;Meerupati et al, 2013), Pfam domain RicinB_lectin_2 (ribosomeinactivating proteins), proteins involved in fungal stress response, cell signaling, organization of the cytoskeleton, vesicular transport and membrane transport, as well as several families of calcium-binding proteins and transcription factors. Domains of enzymes and proteins involved in the carbon, energy and amino-acid metabolism and protein synthesis were also highly expressed by nematode trapping fungi.…”

“…DUF3129 was identified in twelve transcripts among the Top500 most expressed transcripts in the library of M. cionopagum infecting H. schachtii. During A. oligospora infections, this domain was identified in one transcript in A. oligospora infecting M. hapla and in four transcripts in A. oligospora infecting H. schachtii among the Top500 most expressed transcripts (Andersson et al, 2014). DUF3129 is an expanded gene family in nematode-trapping fungi and both M. haptotylum and A. oligospora have 33 genes encoding this domain .…”

“…Among the 97 identified PHI-base genes, 15 were highly expressed by A. oligospora, A. dactyloides and M. cionopagum during infection of plant parasitic nematodes. Virulence associated proteins expressed by nematode-trapping fungi included antioxidant, calcium binding protein, cell signaling (Pkinase), cell signalling (Ras), DEAD-box RNA helicase, membrane transport (Cation transport ATPase (P-type) family, morphogenesis (Serine/threonine-protein phosphatase), non-specific DNA-binding proteins (HMG box), stress response (FKBP-type peptidyl-prolyl cistrans isomerase), stress response (Peptidylprolyl isomerase), transcription (Repressor Tup1), Woronin body major protein (Andersson, et al, 2014). The PHI-base genes that differ in expression between the nematode-trapping fungi included aspartic proteases and the gas 1 and gas 2 proteins of M. grisea (Xue et al, 2000) that contains the DUF3129 domain (domain of unknown function).…”