Grapevine (Vitis spp.) rootstock stilbenoid associations with host resistance to and induction by root knot nematodes, Meloidogyne incognita

Abstract

Objective The root knot nematodes (RKN) Meloidogyne incognita can severely reduce grapevine yields over time. Grapevine rootstocks have been developed from wild Vitis species that provide resistance to nematode infections. However, the potential biochemical or mechanical mechanisms of resistance have not been thoroughly explored. Therefore, this study measured levels of stilbenoids in roots of non-infected and RKN-infected grapevines with Cabernet Sauvignon scion grafted to susceptible (O39-16) or resistant (Freedom) rootstocks. This was part of a larger effort to assess phenolic compound levels within grapevine rootstocks to determine roles of stilbenoid compounds in improving nematode resistance and overall plant health. Results None of the assessed compounds were consistently greater in RKN infected plants versus healthy controls. Stilbenoids putatively identified as pallidol, ɑ-viniferin, miyabenol C, and hopeaphenol were overall much greater in Freedom than O39-16 rootstocks. By contrast, the stilbenoids ampelopsin A, ω-viniferin, and vitisin B were greater in O39-16 than Freedom. O39-16 and Freedom had similar levels of other stilbenoids especially monomers and dimers. Potentially the greater levels of specific stilbenoids present in Freedom than O39-16 provided RKN resistance. If validated, breeding programs could utilize the increased presence of these compounds as a marker for increased resistance to nematodes.

Phenolic Compound Induction in Plant-Microbe and Plant-Insect Interactions: A Meta-Analysis

“…However, poor representation of studies likely influenced these conclusions (nine or less cases for inductions of total phenolics, flavonoids, and hydroxycinnamic acid derivatives). Clearly, future studies are warranted to examine phenolic induction by oomycetes, nematodes, parasitic plants, and viruses, albeit a handful of studies suggests induction is expected (Wallis and Sudarshana, 2016 ; Wallis, 2020 ).…”

A Phytochemical Perspective on Plant Defense Against Nematodes

“…A third conclusion is that several studies cited in this review report that the total concentration of a certain class of secondary metabolites is uncorrelated to PPN resistance, whereas the concentration of one or more specific, often low-abundance, metabolites within that class does show a strong correlation with resistance. Examples of this phenomenon in this review are found among terpenoid aldehydes in cotton (Veech, 1978(Veech, , 1979Hedin et al, 1984;Khoshkhoo et al, 1994a;Alves et al, 2016), flavonoids in soybean (Kaplan et al, 1980a,b;Huang and Barker, 1991;Kennedy et al, 1999;Carpentieri-Pipolo et al, 2005;Kang et al, 2018), stilbenoids in grapevine (Wallis, 2020), benzoxazinoids in wheat (Frew et al, 2018), and glucosinolates in canola (Potter et al, 1998(Potter et al, , 1999. This observation stresses the importance of using analytical approaches that identify individual metabolites (e.g., HPLC-or GC-MS) instead of relying on less discriminatory techniques such as colorimetric assays.…”

“…A comparison of two grapevine (Vitis vinifera) rootstocks, one of which was susceptible to M. incognita and one of which was resistant, also hinted at a possible role for stilbenoids in nematode resistance (Wallis, 2020). The two rootstocks (both with Cabernet Sauvignon as the scion) were inoculated with M. incognita and sampled 6 and 12 weeks postinoculation.…”

Microplate bioassay to examine the effects of grapevine-isolated stilbenoids on survival of root knot nematodes

“…Such compounds could be phenolics called stilbenoids [ 9 , 10 ]. Previous studies did not observe correlations between nematode counts and rootstock stilbenoids [ 11 ]. However, various factors could have impacted such results and more direct assessments were deemed warranted.…”

“…Thus, an experiment was conducted to assess stilbenoid compound effects on root knot survival. Instead of using adult nematodes, this study involved the J2 mobile stage, as it was hypothesized that stilbenoids might impact initial establishment into plant roots [ 4 , 11 ]. A variety of stilbenoids were assessed, ranging from monomers to dimers to trimers to tetramers.…”