A nematode host-range paradox: how can one of the apparently most specialised obligate biotrophic plant-parasites also have the largest host rangeNemHostRangeParadoxA nematode h

The root-knot nematode (Meloidogyne incognita) is an obligate biotrophic pathogen with a remarkable ability to deliver “effector” molecules into its host plant, allowing it to reproducibly and exquisitely alter plant immunity, development, and physiology.

Paradoxically, this nematode also has the widest host range of any obligate biotroph: parasitizing more than 3,000 different species.

I hypothesize that the polyploid nature of its genome allows it to harbor an “effector” repertoire that not only allows for this broad host range, but its differentially deployed across its host range.

To address this hypothesis, we have carefully pre-selected plant species across the botanical orders covering the main groups across the phylum.

We will infect each species with M. incognita and, in a “trans-kingdom linked transcriptome” we will analysed nematode gene expression, and plant gene expression, at the same time in each susceptible interaction.

These data will allow us to determine: 1) Is there a core set of effectors that are invariantly deployed, independent of host, and/or are subsets “chosen” for particular hosts or groups of hosts?; 2) Are there conserved plant genes manipulated by M. incognita during the infection?; and 3) Finally, are some plant or nematode genes required for specific interactions or group of interactions?

These data will allow us to address a long-standing question in the field, and I believe understanding how M. incognita can infect such a broad host range may be a key to future control.