Lignin nanoparticles containing essential oils for controlling Phytophthora cactorum diseases

Abstract

Phytophthora cactorum is a plant pathogen affecting a wide range of hosts, causing economically damaging diseases, such as damping off and root rot, in fields and nurseries. Current plant protection strategies are often inadequate to control Phytophthora diseases. Hence, an attempt was made to evaluate the potential of a novel control method using lignin nanoparticles loaded with essential oil of Thymus serpyllum (EO-LNPs) for controlling P. cactorum infections on Pinus nigra in vitro and greenhouse conditions. Nanoparticles were characterized by Py-GCMS and the drug efficiency, and drug loading capacity were determined using HPLC. T. serpyllum essential oils (EOs) were characterized by gas chromatography (GC-FID and GC-MS). Under in vitro conditions, the median effective concentration (EC50) values were 20.453 and 88.711 μg/ml, for EOs and EO-LNPs, respectively. Furthermore, in vivo tests revealed that thyme EOs and EO-LNPs were very effective in reducing the mortality of inoculated pine seedlings, with an inhibition rate of 93% and 100%, respectively. Results reported in this study open the possibility of using EO-LNPs for improving plant health in greenhouse settings. The design of new protection strategies relying on lignin nanoparticles conforms to the principles of the circular economy.