Underground mystery: Interactions between plant roots and parasitic nematodes

Plant parasitic nematodes (PPN) are microscopic roundworms that mostly develop an obligate parasitic relationship with hosts. Once PPN reach root surfaces, they slowly insert a stylet, needle-like structure, into and feed cytosolic nutrients from roots, which cause cell and tissue mortality (Fosu-Nyarko and Jones, 2016; Mitchum et al., 2013). Recently, these PPN-associated damages have become of great agricultural and economic importance resulting in an estimated annual loss of ∼14 percent of world crop production (Nicol et al., 2011). Thus, an urgent breakthrough is needed in developing effective and sustainable pest management programs such as new resistance cultivars. It is however not necessarily forthcoming, largely due to our little knowledge of the defense physiology of plants against PPN. Hence, this review will briefly revisit current working models of plant and PPN interactions with a focus of plant defense responses, and pinpoint information gaps within, which help revamp unique and alternative prospective for the future studies. Keywords: Plant parasitic nematodes (PPN), Hypersensitive response, Host specificity of PPN, Chemotaxis, Root exudate