Poster: Biology & Disease Mgmt: Nematology
Root knot nematode effects on metabolic profiles of susceptible and resistant grapevine rootstocks
C. Wallis (1); (1) USDA-ARS
Root knot nematodes (Meloidogyne spp.) can negatively impact newly planted and stressed vineyards. Nematode infestations also may increase grapevine susceptibility to other stresses such as water deficit or various diseases. However, little is known about direct or indirect effects of nematode feeding on grapevine physiology, or potential underlying mechanisms that impart resistance to certain rootstock cultivars. Therefore, this study assessed metabolite profiles in Cabernet Sauvignon grapevines grafted to either susceptible (O39-16) or resistant (Freedom) rootstocks established in root knot nematode-infested soil or steam-sterilized soil. Grapevines of both cultivars grown in soil infested with nematodes had reduced fructose and glucose levels compared to control grapevines grown in non-infested soil. Phenolic profiles in resistant grapevines did not differ due to exposure to nematodes, and only a few phenolic compounds increased in susceptible grapevines due to nematode feeding. Regardless of the presence of nematodes, root phenolic profiles between resistant and susceptible rootstocks were dissimilar, with different individual compounds more prevalent in one cultivar than the other. Taken together, these results demonstrated that nematode infestations altered root physiology, and that resistant grapevines expressed phenolic profiles different from susceptible grapevines.