Biopesticide Compounds from an Endolichenic Fungus <i>Xylaria</i> sp. Isolated from the Lichen <i>Hypogymnia tubulosa</i>
Fotios A. Lyssaios, Azucena González-Coloma, María Fe Andrés
et al.
Endolichenic fungi represent an important ecological group of microorganisms that form associations with photobionts in the lichen thallus. These endofungi that live in and coevolve with lichens are known for synthesizing secondary metabolites with novel structures and diverse chemical skeletons making them an unexplored microbial community of great interest. As part of our search for new phytoprotectants, in this work, we studied the endolichenic fungus <i>Xylaria</i> sp. isolated from the lichen <i>Hypogymnia tubulosa</i>, which grows as an epiphyte on the bark of the endemic Canarian tree <i>Pinus canariensis</i>. From the extract of the liquid fermentation, we isolated two unreported piliformic derivatives, (+)-9-hydroxypiliformic acid (<b>1</b>) and (+)-8-hydroxypiliformic acid (<b>2</b>), along with four previously reported compounds, (+)-piliformic acid (<b>3</b>), hexylaconitic acid A anhydride (<b>4</b>), 2-hydroxyphenylacetic acid (<b>5</b>), and 4-hydroxyphenylacetic acid (<b>6</b>). Their structures were elucidated based on NMR and HRESIMS data. The extract and the isolated compounds were tested for their insect antifeedant (<i>Myzus persicae</i>, <i>Rhopalosiphum padi</i>, and <i>Spodoptera littoralis</i>), antifungal (<i>Alternaria alternata</i>, <i>Botrytis cinerea</i>, and <i>Fusarium oxysporum</i>), nematicidal (<i>Meloidogyne javanica</i>), and phytotoxic effects on mono- and dicotyledonous plant models (<i>Lolium perenne</i> and <i>Lactuca sativa</i>). Compounds <b>4</b>, <b>5</b>, and <b>6</b> were effective antifeedants against <i>M. persicae</i> and <b>4</b> was also active against <i>R. padi</i>. Moreover, <b>3</b> and <b>4</b> showed antifungal activity against <i>B. cinerea</i> and <b>4</b> was the only nematicidal. The extract had a strong phytotoxic effect on <i>L. sativa</i> and <i>L. perenne</i> growth, with compounds <b>3</b>, <b>4</b>, and <b>5</b> identified as the phytotoxic agents, while at low concentrations compounds <b>3</b> and <b>4</b> stimulated <i>L. sativa</i> root growth.
Dynamic Assembly of Microgels and Polymers at Non‐Aqueous Liquid/Liquid Interfaces
Xin Guan, Yang Liu, Lianwei Li
et al.
Abstract Particle assembly at liquid–liquid interfaces presents a promising bottom‐up strategy for creating supramolecular materials with advanced functionalities. However, the significantly lower interfacial tension observed in immiscible organic phases compared to traditional oil–water systems has hindered the effective adsorption and assembly of particles at oil–oil interfaces. In this work, a versatile and effective strategy is presented that utilizes the assembly and jamming of microgels and polymer ligands at non‐aqueous liquid–liquid interfaces to create non‐aqueous Pickering emulsions and reconfigurable droplet networks. The resulting microgel‐polymer complexes form an asymmetric interfacial bilayer with high surface coverage, which effectively minimizes interfacial energy and improves interfacial elasticity. Through a combination of systematic interfacial measurements and molecular dynamics simulations, the underlying mechanisms governing interfacial self‐assembly are elucidated. Notably, the stimuli‐responsive nature of the microgel‐polymer complexes allows for precise control over the interfacial assembly and disassembly by introducing competitive molecules. Furthermore, it is demonstrated that these non‐aqueous Pickering emulsions serve as excellent templates for the fabrication of heterogeneous organogels and microgel‐based colloidosomes through both covalent and non‐covalent crosslinking strategies. This work underscores the potential of non‐aqueous interfaces in advancing materials science and opens new avenues for developing multifunctional materials.