Analysis of survival and hatching transcriptomes from potato cyst nematodes, Globodera rostochiensis and G. pallida

Abstract

Potato cyst nematodes (PCNs), Globodera rostochiensis and G. pallida, cause important economic losses. They are hard to manage because of their ability to remain dormant in soil for many years. Although general knowledge about these plant parasitic nematodes has considerably increased over the past decades, very little is known about molecular events involved in cyst dormancy and hatching, two key steps of their development. Here, we have studied the progression of PCN transcriptomes from dry cysts to hatched juveniles using RNA-Seq. We found that several cell detoxification-related genes were highly active in the dry cysts. Many genes linked to an increase of calcium and water uptake were up-regulated during transition from dormancy to hydration. Exposure of hydrated cysts to host plant root exudates resulted in different transcriptional response between species. After 48 h of exposure, G. pallida cysts showed no significant modulation of gene expression while G. rostochiensis had 278 differentially expressed genes. The first G. rostochiensis significantly up-regulated gene was observed after 8 h and was coding for a transmembrane metalloprotease. This enzyme is able to activate/inactivate peptide hormones and could be involved in a cascade of events leading to hatching. Several known effector genes were also up-regulated during hatching.

Aphid Colonization Affects Potato Root Exudate Composition and the Hatching of a Soil Borne Pathogen

“…A Globodera neprilysin gene has been detected as the first transcript to be upregulated in eggs treated with host root exudate ( Duceppe et al, 2017 ), therefore we tested the expression of Gpa-nep-1 in G. pallida eggs that had been incubated in non-infested control and aphid-infested PRE. There was a significant increase in the expression of Gpa-nep-1 in unhatched G. pallida eggs 8 days post incubation in root exudates from non-infested control plants relative to eggs incubated in water ( Figure 6A ).…”

“…The effect of sugars on hatching also correlated with an increase in Gpa-nep-1 transcript within the eggs. In a previous study, a role in hatching has been proposed for this gene as it is the first Globodera transcript to be upregulated post-treatment with root exudates from host plants ( Duceppe et al, 2017 ). This study reinforces that proposed link as it correlates the hatching ability of the exudate with expression levels of the gene.…”

“…The compounds required for nematode hatch and the mechanisms behind eclosion remain poorly characterized. Additionally, the majority of genes involved in the hatching response has not been uncovered, however, a G. rostochiensis neprilysin gene ( Gro-nep-1 ) was identified as the first transcript to be upregulated in eggs treated with host root exudate ( Duceppe et al, 2017 ).…”

Transcriptome-wide selection of a reliable set of reference genes for gene expression studies in potato cyst nematodes (Globodera spp.)

“…This study took advantage of a recently published transcriptome dataset from a G . rostochiensis hatching experiment conducted by our team [ 18 ]. These data (NCBI bioproject accession number PRJNA274143) include sampling at different life stages, including dry cyst, hydrated cyst, hydrated cyst soaked in PRD for 1 h, 8 h, 24 h, 48 h, and 7 d, and fully hatched infective larvae (J2).…”

Impacts of Root Metabolites on Soil Nematodes

“…This enzyme is known to activate/inactivate peptide hormones and may be involved in a cascade of events leading to hatching. After 48 h of exudate exposure, G. rostochiensis had 278 differentially expressed genes, several of which are known effector genes (Duceppe et al, 2017).…”