First Insight Into Multiple Paternity in the Potato Cyst Nematode Globodera pallida Facing Masculinizing Plant...

Polyandry is a common reproductive behaviour in nature, and it was observed in several plant parasitic cyst nematodes. For the potato cyst nematode Globodera pallida, polyandry is assumed but has never been demonstrated and quantified. Since the potato resistance used to control this nematode, i.e., the resistance conferred by GpaV from Solanum vernei, acts by masculinizing populations, and because polyandrous mating is more frequent in male-skewed populations, the level of polyandry can be expected to decrease during the nematode adaptation process to potato resistance. Aims of this study were thus to determine whether polyandry occurs in G. pallida and to explore the polyandry evolution during the adaptation process to the potato resistance. Using G. pallida lineages obtained from experimental evolution on susceptible and resistant potato cultivars, we explored and quantified the genetic evidences of multiple paternity within cysts by genotyping juveniles using microsatellite loci. Results clearly highlighted multiple paternity in G. pallida and showed that 100% of females were polyandrous, with an average of seven fathering males. Contrary to our expectations, the frequency of polyandrous females and the female mating rate with different males, estimated from the minimum number of fathers, appeared to remain stable throughout the adaptation process to a masculinizing resistance. The level of polyandry highlighted here may represent an important parameter to consider in demo-genetic models designed to compare nematode population control strategies.