© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)., Plant essential oils (EOs) are gaining interest as biopesticides for crop protection. EOs have been recognized as important ingredients of plant protection products including insecticidal, acaricidal, fungicidal, and nematicidal agents. Considering the growing importance of EOs as active ingredients, the domestication and cultivation of Medicinal and Aromatic Plants (MAPs) to produce chemically stable EOs contributes to species conservation, provides the sustainability of production, and decreases the variations in the active ingredients. In addition to these direct effects on plant pests and diseases, EOs can induce plant defenses (priming effects) resulting in better protection. This aspect is of relevance considering that the EU framework aims to achieve the sustainable use of new plant protection products (PPPs), and since 2020, the use of contaminant PPPs has been prohibited. In this paper, we review the most updated information on the direct plant protection effects of EOs, focusing on their modes of action against insects, fungi, and nematodes, as well as the information available on EOs with plant defense priming effects., This work was supported by grants from ERASMUS+ European Hub on New Challenges in the Field of Essential Oils (EOHUB) and PID2019-106222RB-C31/SRA (State Research Agency, 10.13039/501100011033). S.K. and S.S. were funded by an international PhD fellowship from the UPM-Algerian Government., Peer reviewed

Every year, more than 50 million tons of Helianthus annuus L. are produced mainly for the sunflower oil industry. It is a plant consumed worldwide, due to its use in feeding and traditional medicine for the prevention of some cardiovascular diseases, as anti-inflammatory, antimicrobial, antioxidant and antihypertensive, among others. Sunflower has a great diversity of metabolites, being especially rich in terpene compounds with close to 400 different molecules reported, including volatile mono and sesquiterpenes. Among these terpenic components of sunflower, sesquiterpenes as helibisabonols, helianuols and heliangolides, diterpenes (ent-kaurenes or ent-trachylobanes and ent-atisarenes compounds) or apocarotenoids (ionone compounds and strigolactones) are worthy to be underlined. Many of these compounds have allelopathic activity. On the other hand, sesquiterpene lactones and diterpene compounds have strong insect antifeedant, antifungal and allelopathic activities. Additionally, the essential oil (rich in α-pinene) has antifungal properties. All these biological activities suggest that Helianthus annuus has great potential for natural crop protection. Since the main sunflower crop residue is the flower head, we have revised the plant-protection properties of flowerhead components to highlight the potential valorization of that residue for the production of biopesticides., This research has been funded by grants MINISTERIO DE ECONOMÍA Y COMPETITIVIDAD, PID2019-106222RB-C32/SRA (State Research Agency, 10.13039/501100011033), PID2019-106222RB-C31/SRA (State Research Agency, 10.13039/501100011033 and Unidad Asociada UGR-CSIC Bioplaguicidas: Biotecnología, síntesis y diversidad química., Peer reviewed

Fungal endophytes have emerged as a promising strategy for sustainable crop management, due to their remarkable ability to synthesize a wide array of secondary metabolites with beneficial effects on plants. These microorganisms establish asymptomatic relationships within plant tissues and can produce bioactive compounds with biocidal properties. Despite promising advances, the mechanisms of symbiosis remain unclear and there is a lack of in-depth analysis on the chemical characterization of their metabolites. This review compiles and discusses the current discoveries on 180 metabolites summarized according to their biological activities (insecticidal, antifungal, phytotoxic, nematicidal and antibacterial), highlighting their potential applications as biocontrol agents for integrated crop protection strategies. As a future perspective, the use of next-generation sequencing (NGS) technologies such as metagenomics in endophytic fungi research is emphasized for its promise in elucidating complex plant–microbe interactions and guiding bioprospecting efforts to identify fungal taxa capable of producing agriculturally relevant bioactive compounds. This review aims to summarize recent advances in the field, highlighting the potential uses of endophytic compounds in plant health, disease suppression, and resistance enhancement, while also identifying current limitations and outlining future research directions to further expand this promising area., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been supported by grant PID2019-106222RB-C31/SRA MCIN/AEI/https://doi.org/10.13039/501100011033. Jorge Rojas López-Menchero has been supported by a predoctoral contract FPI associated to the project PID2019-106222RB-C31 funded by MCIN/AEI/ 10.13039/ 501100011033 and FSE “El FSE invierte en tu futuro”. Fotyos A. Lyssaos thanks to ACIISI of the Canary Islands Government for a predoctoral contract and thesis/work is co-financed by the Canary Islands Agency for Research, Innovation and Information Society of the Regional Ministry of Economy, Knowledge and Employment and by the European Social Fund (ESF) Canary Islands Integrated Operational Program 2014–2020, Axis 3 Priority Theme 74 (85%)., Peer reviewed