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Plant resistance includes mechanical and chemical defenses that reduce herbivory, whereas plant tolerance reduces the fitness impact of herbivory. Because defenses are costly and investing in both resistance and tolerance may be superfluous, trade‐offs among them are expected. In forest ecosystems, the mechanical strengthening of leaves is linked both to shade adaptation and antiherbivore defenses, but it also compromises resource uptake, therefore limiting regrowth following damage, suggesting a trade‐off between mechanical defenses and tolerance. We tested for the resistance–tolerance trade‐off across 11 common tree species in a temperate rainforest and explored mechanistic explanations by measuring chemical and mechanical defenses. Herbivory damage was negatively associated with leaf toughness and fiber content, whereas there was no significant relationship between herbivory and secondary metabolites (flavonols, gallic acid, tannins, and terpenoids). We detected a resistance–tolerance trade‐off, as expected. We found a negative relationship between mechanical defenses and tolerance, estimated as the survival ratio between experimentally damaged and undamaged seedlings. Tolerance and secondary metabolites showed no significant association. Results suggest that selective forces other than herbivory acting on defensive traits can favor a resistance–tolerance trade‐off. Therefore, plant adaptation to contrasting light environments may contribute to the evolution of resistance–tolerance trade‐offs. [ABSTRACT FROM AUTHOR]

Despite the ubiquitous presence of fungal endophytes in woody plants, mechanisms underlying variation in foliar fungal endophyte communities are poorly understood. Given that endophytes in woody plants are predominantly horizontally transmitted, fungal endophyte colonization of foliar tissues is likely to be influenced by plant resistance traits. Here, we evaluated the association between leaf resistance traits and colonization and community composition of horizontally transmitted endophytes (HTE) in 10 dominant trees species in a temperate rainforest in Southern Chile. Because resistance traits might restrict colonization of HTE, it was hypothesized that host trees with similar leaf resistance traits would show similar HTE communities.We measured leaf traits with reported roles in plant resistance against pathogens and/or herbivores: cell wall polysaccharides, leaf toughness, flavonoids, anthocyanins, terpenoids and chitinases. We also determined variation in fungal read counts, number of operational taxonomic units (OTUs), diversity and community structure across tree species. Foliar fungal endophyte communities were characterized using Illumina MiSeq sequencing of tagged amplicons of the ITS1 region.Fungal read counts were significantly different among host trees, while number of OTUs and diversity were similar among them. Multivariate analyses showed that community composition of endophytic fungi significantly differed among hosts, and that variation in cell wall, flavonoids, anthocyanins and terpenoids was associated with differences in HTE communities. We found that host trees sharing leaf resistance traits harbour similar HTE communities. Fungal read counts decreased with increasing content of cell wall polysaccharides, while endophyte diversity decreased with increasing anthocyanin levels. Fungal read counts, in contrast, were positively associated with terpenoids. Additionally, culture‐based data indicated that some HTE strains inhibited the growth of the common fungal pathogen Botrytis cinerea.Synthesis. Overall, we found that leaf resistance traits may influence fungal endophyte colonization and community composition in tree species, likely through deterrent effects of structural and chemical traits. We suggest that endophytic fungi that overcome resistance traits might play a role in plant protection. [ABSTRACT FROM AUTHOR]

Two labdane diterpenoids were isolated, from the resinous exudate of Haplopappus velutinus Remy (Asteraceae); the main compound was identified as 7,13-(E)-labdadien-15,18-dioic-acid-18-methyl ester (1) and the minor compound identified as 7-labden-15,18-dioic-acid-18-methyl ester (2). Their structures were obtained using FTIR, MS, HRMS and NMR data: 1D NMR (1H, 13C and DEPT-135), 2D homonuclear NMR (COSY and NOESY) and heteronuclear NMR (HSQC and HMBC). The trans stereochemistry of the decalin moiety of compounds 1 and 2 was established through NOESY experiments of the reduction product of 1; 7-labden-15,18-diol (1a). Diterpenoids 1 and 1a are described for the first time and showed antifungal activity, inhibiting approximately 40% mycelial growth of Botrytis cinerea. [ABSTRACT FROM AUTHOR]

Aims Desertification is a major concern in arid and semi-arid regions globally. Understanding interactions between vulnerable plant species and associated microbial symbionts may have important applications for conservation and restoration strategies in affected areas. Methods In this study, we evaluated the root-associated fungal endophyte community in Prosopis chilensis, a vulnerable and threatened arid-adapted tree of northern Chile. Host benefits in terms of physiological performance and plant growth were also assessed. Endophytic fungi were isolated from asymptomatic roots by the culture method for molecular identification of the 18S rRNA gene. The dominant fungal endophyte (Penicillium sp.) in the community was later used in inoculation experiments to assess its effect on maximum quantum efficiency of photosystem II (PSII), (F v/ F m) actual PSII efficiency (Φ PSII), and non-photochemical quenching (NPQ). Total sugars, starch content, malonaldehyde (MDA), nitrogen content (%) and growth traits were also measured. Important Findings Whereas Φ PSII increased significantly in endophyte-inoculated plants, NPQ was found to decrease. No effect of endophyte inoculation on sugars and MDA was detected, but starch content, leaf nitrogen content, number of leaves and shoot biomass were found to increase. Results revealed that inoculation of endophytic Penicillium fungal isolate can provide significant physiological benefits to the host plant P. chilensis. Its presence resulted in greater PSII efficiency and higher leaf nitrogen and carbohydrate content, enhancing host plant growth. These findings highlight the importance of considering the fungal endophyte community of this vulnerable species as an important tool to the design of further revegetation and conservation programs. [ABSTRACT FROM AUTHOR]

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