Altitude-related changes in the phytochemical profile of essential oils extracted from Artemisia nilagirica and their nematicidal activity against Meloidogyne incognita

Abstract

Essential oils (EOs) are considered to be the most suitable alternatives for plant pathogen management, as they exhibit high potency and favourable ecotoxicological profile. The present study evaluated the nematicidal activity of high and low land Artemisia nilagirica (C.B.Clarke) pamp EOs (AnEOs) under laboratory and greenhouse conditions. The AnEOs were extracted from the aerial parts of high (AnEO-H) and low altitude (AnEO-L)-grown A. nilagirica by using Clevenger-type apparatus and their compositional variation in chemical constituents were determined by gas chromatography-mass spectrometry (GC–MS) analysis. It was observed that the difference in altitude had a huge impact on nature, quantity, appearance, yield, and chemical composition of AnEOs. Further, AnEO-H and AnEO-L exhibited a significant difference in nematicidal activity against Meloidogyne incognita (Kofoid et White) Chitwood with a lethal concentration (LC50/48h) of 5.75 and 10.23 μg/mL, respectively. In addition, AnEOs profoundly reduced the root infection of M. incognita in tomato plants (Solanum lycopersicum L.) and significantly promoted plant growth under greenhouse conditions. Further, the greatest strength of Caenorhabditis elegans was utilized as a model to elucidate the nematicidal mechanism of AnEOs, and the results demonstrated that AnEOs exposure could have enhanced the intracellular reactive oxygen species production and germline cell apoptosis. The mechanistic study revealed that AnEOs exposure potentially induces apoptosis by activating the signaling pathway for DNA damage checkpoint and core components of apoptotic machinery in nematodes. Together, the results achieved from this study will lead to a better understanding of the mechanism of AnEOs against M. incognita and will pave the way for the development of novel nematicides with increased efficacy for nematode control.