Xylariaceous endophytes are commonly encountered in plants, and it has recently been found out that insect vectors play a major role in their life cycle, as well as in the apparent host-specificity of the fungal stromata. In this study, a new insect-associated, endophytic anamorph species of Daldinia is recognised from a comparison of a) morphological and ecological data; b) molecular phylogenetic data based on rDNA, alpha-actin and beta-tubulin genes; and c) secondary metabolite profiles based on high performance liquid chromatography/diode array/mass spectrometry (HPLC-DAD/MS) and gas chromatography/mass spectrometry (GC-MS) in comparison with authentic strains of Daldinia and other Xylariaceae. The new species, Daldinia hawksworthii, is a symbiont of the willow woodwasp, Xiphydria prolongata, which is in turn preferentially associated with Salix. A comparison of HPLC-DAD/MS profiles from standardised cultures revealed the presence of a specific compound, which was not encountered in any of the ca. 250 Daldinia strains studied for comparison. This compound was isolated after fermentation of the fungus in 10 l scale by preparative chromatography. Structure elucidation by NMR spectroscopy revealed a novel pyrone, for which the name dalsymbiopyrone is proposed. The compound showed weak antimicrobial and cytotoxic effects and might be a signal molecule involved in the trilateral ecological interaction between the host plant, the insect, and its fungal symbiont.

Research Highlights: Although a number of forestry studies have found that hydrogel improves tree performance, studies that are located in semi-arid regions and that include a broad spectrum of tree species and the assessment of multiple physiological traits are lacking. Background and Objectives: The objective of the current study was to evaluate the effects of hydrogel treatments (with sawdust, organic fertilizer, compost, wheat straw, subsoil, or subsoil with a cobble cover) applied during planting on the survival, growth, and physiological traits of 20 tree species. Materials and Methods: In a field experiment (factorial design with seven treatments including a control, 20 species, and ten replicates) in a semi-arid part of Iran, we applied water alone (control) or water with hydrogel and other materials to recently planted samplings. We evaluated tree height, health, osmotic potential, and biochemical properties after 6 months and survival after 12 months. Results: Hydrogel treatment (regardless of other material) significantly improved the performance of drought-sensitive but not of drought-tolerant species. Conclusions: The benefits of hydrogel treatment are substantial for drought-sensitive species but are insignificant for drought-resistant species.