Cross-kingdom communication between plants and parasitic nematodes

Plant-parasitic nematodes and their hosts engage in a continuous exchange of signals cross-kingdom. On the one hand, parasites exploit host-derived metabolites, proteins, and RNAs to sense host identity, proximity, and condition - and as a basis for manipulating host processes to their benefit. On the other hand, hosts respond to nematode-derived pheromones, proteins, and metabolites to either subvert or accommodate parasitism. Our recent understanding is that microbes play a role mediating, at least in part, a communication, which ultimately shapes the developmental trajectories of both host and parasite, in concert. In this Tansley insight, we review the current understanding of communication between plants and parasitic nematodes, framed by the developmental timeline. We focus on notable, reciprocal signals between plant and parasite that gate key life cycle transitions in the parasite, while acknowledging that these processes are embedded within, and inseparable from, a plethora of other signals - and indeed communication with other organisms. The frequency, reciprocity, and gravity of the exchange leads us to argue that it is best described as a nuanced communication, in which parasitism succeeds or fails based on interpretation and response.