[Description of methods used for collection/generation of data] Experiment performed in the laboratory and semifield conditions, following details described in the publication., [Methods for processing the data] R software version 4.3.2 (R Core Team, 2023). All graphs were built using ggplot2 package., Viticulture is a global activity that annually yields over eighty million tonnes of grapes, 50 % used in winemaking. Traditional viticultural practices still rely on hazardous pesticides, posing environmental and health risks. Recently, Xenorhabdus and Photorhabdus, symbiotic bacteria of entomopathogenic nematodes, have arisen as eco-friendly solutions for pest and disease management in vineyards. However, whether their application can impact the quality attributes of grapes and their microbiota remains unexplored. To unravel the possible impact, we investigated (i) the impact of direct application on grapes' volatile composition and (ii) the combination with must and Saccharomyces cerevisiae fermentation. First, we applied unfiltered ferments (UFs) of Xenorhabdus nematophila and Photorhabdus laumondii to grapes of Vitis vinifera var. "Tempranillo". The volatile composition of the grapes was evaluated using solid-phase and gas chromatography-mass spectrometry (SPE-GC/MS). Second, microfermentations using reconstituted must media were supplemented (1:10) with the treatments (i) cell-free supernatants (CFS), (ii) UFs, and (iii) free-bacterial from X. nematophila and P. laumondii. No significant alterations in the total free volatile fraction were observed, although specific free volatiles (phenylethyl alcohol, hexanal and E-2-hexenal), exhibited significant variation under specific treatments. In the glycosidically bound fraction, phenylacetic acid concentrations increased markedly with X. nematophila UFs. In the fermentations, the treatments had no significant impact on CO2 production kinetics, only slightly affecting some fermentation parameters, underscoring their compatibility with yeast-driven fermentation processes. These findings suggest that Xenorhabdus and Photorhabdus can be safely integrated into vineyard pest management strategies without adversely affecting essential winemaking parameters or grape aroma quality., Ministry of Science and Innovation, grants PID2019-104112RB-I00 and PID2022-136487OB-I00 (MCIN/AEI/10.13039/50110001103)., Support for researchers: The predoctoral contract FPI-UR 2021 (University of La Rioja) support IVD., Peer reviewed

Experiment performed in the laboratory, following details described in the publication, Ministry of Science and Innovation, grant PID2022-136487OB-I00 (MCIN/AEI/10.13039/50110001103 and and by “ERDF A way of making Europe").

Wallonia project (D65-1401/S1, Belgium)

Interreg (0100226 - Trans-Pest)

The predoctoral contract for Andrea Chacón-Hurtado FRIA/FC-2576 FC46977, Peer reviewed

Root-knot nematodes (RKNs) cause major yield losses in horticultural systems worldwide. With increasing restrictions on chemical nematicides, environmentally sustainable alternatives such as entomopathogenic nematodes (EPNs) and derivatives of their symbiotic bacteria are gaining attention. However, it remains unclear how EPNs and their bacterial products might influence RKN behavior. This study investigated the behavioral responses of the RKN Meloidogyne incognita to EPN-derived treatments, testing the hypothesis that these cues induce directional avoidance when RKNs are given a choice, and that such responses may be modulated by plant presence. Experiments were conducted using two-choice horizontal tube systems filled with moistened sand with and without tomato seedlings ( Solanum lycopersicum cv. Moneymaker). Three EPN Steinernema species were assessed: S. feltiae , S. carpocapsae , and S. riojaense . Treatments included (i) EPN infective juveniles (IJs), (ii) EPN-infected Galleria mellonella cadavers, and (iii) bacterial cell-free supernatant (CFS) derived from Xenorhabdus spp. After inoculation of 1500 M. incognita second-stage juveniles (J2s) into the central tube section, nematode movement was quantified after seven days. Although overall J2 mobility was generally low, with most individuals remaining near the inoculation point, clear patterns still emerged: J2 showed a significant avoidance of EPNs and their derivatives, with the strongest responses observed for cadaver and CFS treatments. Plant presence did not markedly change J2 behavioral patterns; repellency occurred regardless of plant cues, although the presence of plants slightly amplified the effect. These findings advance our understanding of how EPNs and by-products influence RKN behavior, revealing early behavioral barriers that may shape rhizosphere interactions., Ministry of Science and Innovation, grant PID2022-136487OB-I00 (MCIN/AEI/10.13039/50110001103 and and by “ERDF A way of making Europe").

The use of the entomopathogenic nematodes described in this study was conducted under permit reference number ESNC 273, corresponding to the Internationally Recognized Certificate of Compliance (IRCC) with unique identifier ABSCH-IRCC-ES-281207-1

RBP is funded by the Consejería de Innovación (Government of La Rioja, Spain, (Resolution 198/2025, call 2025–2028)
MMGT was awarded a FPI-CAR-2022 fellowship (University of La Rioja, Spain), Peer reviewed

Analysis from laboratory and semifield derived data described in the material and method section in the article, The grant PID2022-136487OBI00 funded by MCIN/AEI/10.13039/501100011033 and by the European Regional Development Fund (ERDF) “A way of making Europe”
The use of the entomopathogenic nematodes described in this study was conducted under permit reference number ESNC 273, corresponding to the Internationally Recognized Certificate of Compliance (IRCC) with unique identifier ABSCH-IRCC-ES-281207-1. This certificate was issued in accordance with the Nagoya Protocol and is registered in the Access and Benefit- haring Clearing-House., Peer reviewed

Analysis from laboratory and semifield derived data described in the material and method section in the article, The grant PID2019-104112RB-I00 (MCIN/AEI/10.13039/50110001103)
The grant PID2022-136487OBI00 (MCIN/AEI/10.13039/501100011033 and by the European Regional Development Fund (ERDF) “A way of making Europe”)
The use of the entomopathogenic nematodes described in this study was conducted under permit reference number ESNC 273, corresponding to the Internationally Recognized Certificate of Compliance (IRCC) with unique identifier ABSCH-IRCC-ES-281207-1. This certificate was issued in accordance with the Nagoya Protocol and is registered in the Access and Benefit- haring Clearing-House.

Support for researchers:

RBP is supported by the Consejería de Innovación (Government of La Rioja, Spain)
MP is funded by the FPI-UR (2022) from the University of La Rioja
JM is funded by PTA2023-022748-I (MCIN/AEI/10.13039/50110001103 and “European Union NextGenerationEU/PRTR"), Peer reviewed