Essential oils produced by plants, and their components, could be sources of new natural herbicidal compounds. Thirteen oils extracted from six wild Lamiaceae species (namely Clinopodium suaveolens (Sm.) Kuntze, Satureja montana L. subsp. montana, Thymbra capitata (L.) Cav., Salvia fruticosa Mill. subsp. thomasii (Lacaita) Brullo, Guglielmo, Pavone & Terrasi, Satureja cuneifolia Ten., and Thymus spinulosus Ten.) from South Italy were tested in vitro for the phytotoxic activity to cress and branched broomrape seeds, tomato radicles, and lambsquarters leaf disks. Moreover, the possible correlation between oil composition and biological activity was evaluated. One of the oils from T. capitata inhibited cress germination by 96.4% at the lowest tested concentration (100 ppm) and reduced both chlorophyll and carotenoid content in lambsquarters leaf disks by around 50%. Some oils, particularly those from T. spinulosus, inhibited tomato radicle elongation by 85% at 1000 ppm. Many oils inhibited broomrape seed germination up to 100% when tested in solution at 1000 ppm or released as vapors. Among the oil components, α-terpinene, p-cymene, β-cis-ocimene, cis-sabinene hydrate, carvacrol methyl ether, and thymol were mostly correlated to the inhibition of cress seeds germination and tomato radicle elongation. The presence of thymol and p-cymene was also correlated to the inhibition of broomrape seed germination. Some of the tested essential oils or their components could have potential as pre-emergence herbicides and could be useful in the development of new weed control strategies.

Drechslera gigantea Heald & Wolf is a worldwide-spread necrotrophic fungus closely related to the Bipolaris genus, well-known because many member species provoke severe diseases in cereal crops and studied because they produce sesterpenoid phytoxins named ophiobolins which possess interesting biological properties. The unfolded protein response (UPR) is a conserved mechanism protecting eukaryotic cells from the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER). In plants, consolidated evidence supports the role of UPR in the tolerance to abiotic stress, whereas much less information is available concerning the induction of ER stress by pathogen infection and consequent UPR elicitation as part of the defense response. In this study, the infection process of D. gigantea in Arabidopsis thaliana wild type and UPR-defective bzip28 bzip60 double mutant plants was comparatively investigated, with the aim to address the role of UPR in the expression of resistance to the fungal pathogen. The results of confocal microscopy, as well as of qRT-PCR transcript level analysis of UPR genes, proteomics, microRNAs expression profile and HPLC-based hormone analyses demonstrated that ophiobolin produced by the fungus during infection compromised ER integrity and that impairment of the IRE1/bZIP60 pathway of UPR hampered the full expression of resistance, thereby enhancing plant susceptibility to the pathogen.

Inuloxin A is a promising plant phytotoxic sesquiterpene that deserves further studies to evaluate its potential as a bioherbicide. However, its low solubility in water and its bioavailability could hamper its practical applications. For this reason, inuloxin A was complexed with β-cyclodextrins by using three different methods, i.e., kneading, co-precipitation and grinding. The resulted complexes were fully characterized by different techniques such as ¹H NMR, UV-vis, XRD, DSC and SEM, and they were biologically assayed in comparison with the pure compound in several biological systems. The efficacy of the kneading and grinding complexes was similar to that of inuloxin A and these complexes almost completely inhibit Phelipanche ramosa seed germination. The complete solubility in water and the preservation of the biological properties of these two complexes could allow further studies to develop a novel natural herbicide for parasitic plant management based on these formulations.

The use of wireless sensors for real-time sensing of substrate water status and electrical conductivity could be an effective tool for precision irrigation management in soilless cultivation. In this research, the effects of timer-based (TB) compared to smart sensor-based irrigation (SB) were investigated. The highest consumption of fertilizers and water were recorded in TB, with nutrient solution and total applied water savings of 38% and 26%, respectively, in SB. The highest yield was obtained in SB treatment, with a total and marketable yield decrease of 7% in TB, with no differences in terms of the total soluble solids content, dry matter, firmness, juice pH and titratable acidity of the strawberry fruits. The higher yield, combined with water and nutrient saving in SB, allowed water use efficiency (fresh weight of marketable fruits per liter of total water applied) to be increased by 46% and nutrient productivity (fresh weight of marketable product per gram of nutrient supplied via nutrient solution) by 74%. The study confirms that sensor-based, compared to empiric fertigation management, ameliorates the sustainability of open, free-drain, soilless cultivation of strawberry, leading to better resource use without compromising crop performance and fruit quality.