Transcriptome analysis of root‐knot nematode functions induced in the early stages of parasitism*

Abstract

Root-knot nematodes of the genus Meloidogyne are obligate biotrophic parasites able to infest > 2000 plant species. The nematode effectors responsible for disease development are involved in the adaptation of the parasite to its host environment and host response modulation. Here, the differences between the transcriptomes of preparasitic exophytic second-stage juveniles (J2) and parasitic endophytic third-stage juveniles (J3) of Meloidogyne incognita were investigated. Genes up-regulated at the endophytic stage were isolated by suppression subtractive hybridization and validated by dot blots and real-time quantitative polymerase chain reaction (PCR). Up-regulation was demonstrated for genes involved in detoxification and protein degradation, for a gene encoding a putative secreted protein and for genes of unknown function. Transcripts of the glutathione S-transferase gene Mi-gsts-1 were 27 times more abundant in J3 than in J2. The observed Mi-gsts-1 expression in the oesophageal secretory glands and the results of functional analyses based on RNA interference suggest that glutathione S-transferases are secreted during parasitism and are required for completion of the nematode life cycle in its host. Secreted glutathione S-transferases may protect the parasite against reactive oxygen species or modulate the plant responses triggered by pathogen attack.

How Durable is Root Knot Nematode Resistance in Tomato?

“…Authors speculated that those molecules could be acting as a facilitator of entering and intercellular movement of the RKN at the early phases of the parasitism. However, presence of different candidate molecules in the nematode secretions supports the thoughts of the NFS formation as well as hypothesis of the parasitism (Ferreira et al 2004;Dubreuil et al 2007;Bellafiore et al 2008). Moreover, a molecule associated to rhizobial Nod factor acting as an initial signal of RKN-plant parasitism (Weerasinghe et al 2005).…”

“…Moreover, a molecule associated to rhizobial Nod factor acting as an initial signal of RKN-plant parasitism (Weerasinghe et al 2005). Recently, gene expression patterns during initiation of the NFS have been examined by various approaches such as transcriptomic analysis (Dubreuil et al 2007), promoter-trapping strategies (Favery et al 2004), in situ hybridizations (Gal et al 2006), quantitative RT-PCR and in situ RT-PCR (Wieczorek et al 2014). Identification of pathogen effectors, function of the effectors in the NFS development as well as mechanism of the parasitism will be more fascinating with the technical advancement in future.…”

Arabidopsis Spermidine Synthase Is Targeted by an Effector Protein of the Cyst Nematode Heterodera schachtii

“…In support, plant-parasitic nematodes themselves are believed to possess an antioxidant machinery to protect their bodies against ROS produced by the host. Putatively secreted enzymes to scavenge ROS, such as superoxide dismutase, CAT, peroxidase, and GPX, have been identified in root-knot and cyst nematodes (Molinari and Miacola, 1997;Robertson et al, 2000;Jones et al, 2004;Dubreuil et al, 2007). It could be that the developing syncytium, required for successful cyst nematode parasitism, needs ROS protection as a safeguard for nematode survival.…”

Plant defense elicitors purification in soybean and bean from pathogenic nematode

“…According to Haegeman et al (2012), the proteins present in nematode secretions are destined to protect the proteins from the host's defense responses. As an example, it is worth highlighting the gluatathione-S-transferase (GST) expressed in M. incognitas pharynx gland (Dubreuil et al, 2007). However, the authors also verified the GST acting on the detoxification of secondary metabolisms that the plant uses to prevent pathogen invasion.…”