The cryptic microbiota of plant parasitic and entomopathogenic nematodes: diversity, effects on host biology and potential in plant protection

Many plant parasitic and entomopathogenic nematodes harbor specialized and obligate bacteria as well as viruses. Given their evolutionary persistence, such cryptic species are considered to play effective roles during their host/microbe interactions lifetime, including mutualistic, antagonistic, or yet unknown host effects. To exploit such associations in plant protection, a comprehensive view is needed linking basic evolutionary relationships to applied aspects. This requires identifying the benefit or impact that hosts, acting as pests or biocontrol agents, receive from their endosymbionts. Targeting endosymbionts that are vital for a beneficial nematode or a pest may open novel perspectives for the management of their performance and traits, such as virulence or response to plant defense reactions. Some hypotheses are proposed to develop advanced control strategies through emerging biotechnological approaches.