RT info:eu-repo/semantics/article T1 Valorization of Quercus suber L. bark as a source of phytochemicals with antimicrobial activity against apple tree diseases A1 Sánchez Hernández, Eva A1 González García, Vicente A1 Casanova Gascón, José A1 Barriuso Vargas, Juan José A1 Balduque Gil, Joaquín A1 Lorenzo Vidal, Belén A1 Martín Gil, Jesús A1 Martín Ramos, Pablo K1 Antimicrobial activity K1 Antifungal K1 Ecology K1 Phytochemicals K1 Fitoquímica K1 Phytopathologie K1 Trees - Diseases and pests K1 Arboles - Enfermedades y plagas K1 Alcornoques K1 Apples K1 Manzanos - Enfermedades y plagas K1 Forests and forestry K1 Bosques y silvicultura K1 Plant science K1 Fruit-culture K1 2417.13 Ecología Vegetal K1 3108 Fitopatología K1 3102 Ingeniería Agrícola K1 3106.08 Silvicultura K1 3107.04 Fruticultura AB Cork, an anatomic adaptation of the bark of Quercus suber L. through its suberization process, finds its main application in the production of bottle stoppers. Its processing results in a large waste stream of cork fragments, granulates, and dust, which may be susceptible to valorization. The work presented here explored the use of its extracts to inhibit the growth of phytopathogenic microorganisms associated with apple tree diseases. The in vitro antimicrobial activity of cork aqueous ammonia extract was assayed against four fungi, viz. Monilinia fructigena and M. laxa (brown rot), Neofussicoccum parvum (dieback), and Phytophthora cactorum (collar and root rot), and two bacteria, viz. Erwinia amylovora and Pseudomonas syringae pv. syringae, either alone or in combination with chitosan oligomers (COS). Effective concentration values of EC90 in the 675–3450 μg·mL−1 range, depending on the fungal pathogen, were obtained in growth inhibition tests, which were substantially improved for the conjugate complexes (340–801 μg·mL−1) as a result of strong synergism with COS. Similar enhanced behavior was also observed in antibacterial activity assays, with MIC values of 375 and 750 μg·mL−1 for the conjugate complexes against P. syringae pv. syringae and E. amylovora, respectively. This in vitro inhibitory activity was substantially higher than those exhibited by azoxystrobin and fosetyl-Al, which were tested for comparison purposes, and stood out among those reported for other natural compounds in the literature. The observed antimicrobial activity may be mainly attributed to the presence of glycerin and vanillic acid, identified by gas chromatography–mass spectroscopy. In the first step towards in-field application, the COS–Q. suber bark extract conjugate complex was further tested ex situ against P. cactorum on artificially inoculated excised stems of the ‘Garnem’ almond rootstock, achieving high protection at a dose of 3750 μg·mL−1. These results suggest that cork industrial leftovers may, thus, be a promising source of bioactive compounds for integrated pest management. PB MDPI SN 2223-7747 YR 2022 FD 2022 LK https://uvadoc.uva.es/handle/10324/69621 UL https://uvadoc.uva.es/handle/10324/69621 LA eng NO Plants, 2022, Vol. 11, Nº. 24, 3415 NO Producción Científica DS UVaDOC RD 23-dic-2024