The PERKs of being resistant – on the exploitation of a novel source of nematode resistance in vegetable crops

The impact of plant-parasitic nematodes on food security has increased significantly over the past few years for two reasons. First, most of the pesticides currently used to control nematodes face a global ban, because of serious environmental and health concerns. Second, rising soil temperatures by global warming and genetic adaptations in nematode populations undermine the use of many major nematode resistance genes in food crops. At present, nematode resistance breeding in tomato and other vegetable crops is based on highly specific resistance genes, most of which appear to be temperature sensitive (>28° C). These circumstances demand the plant breeding industry to refocus on novel types of nematode resistance. However, very little is known of alternative sources of nematode resistance in plants.Recently, I demonstrated that nematodes are far more sensitive to basal host immunity than expected. Unlike highly specific major resistances, basal immunity is regulated in plant cells by surface-localized receptors. These receptors survey the cell exterior for tissue damage that betrays the presence of invaders. Plant parasitic nematodes modify plant cell walls during host invasion and feeding, but how this affects basal immunity is unknown. My thesis work provides first evidence that specific plant cell wall-associated receptors (i.e. PERKs) most likely mediate basal immunity to both cyst and root-knot nematodes. Therefore, the aim of this project is to elucidate the molecular mechanisms underlying the activation of damage-induced basal immunity to plant-parasitic nematodes. I will first use high-resolution transcriptomics to study Arabidopsis knockout mutants lacking these specific plant cell wall-associated receptors. This will enable me to further identify and characterize downstream mechanisms underlying basal immunity activated by nematode-induced damage in plants. Natural genetic variation in key regulators of damage-induced host defences can ultimately be exploited in breeding programs to develop novel cultivars with enhanced broad-spectrum basal resistance to nematodes.