Recent Advances in Grayanane Diterpenes: Isolation, Structural Diversity, and Bioactivities from Ericaceae Family (2018-2024)

Diterpenes represent one of the most diverse and structurally complex families of natural products. Among the myriad of diterpenoids, grayanane diterpenes are particularly notable. These terpenes are characterized by their unique 5/7/6/5 tetracyclic system and are exclusive to the Ericaceae family of plants. Renowned for their complex structures and broad spectrum of bioactivities, grayanane diterpenes have become a primary focus in extensive phytochemical and pharmacological research. Recent studies, spanning from 2018 to January 2024, have reported a series of new grayanane diterpenes with unprecedented carbon skeletons. These compounds exhibit various biological properties, including analgesic, antifeedant, anti-inflammatory, and inhibition of protein tyrosine phosphatase 1B (PTP1B). This paper delves into the discovery of 193 newly identified grayanoids, representing 15 distinct carbon skeletons within the Ericaceae family. The study of grayanane diterpenes is not only a deep dive into the complexities of natural product chemistry but also an investigation into potential therapeutic applications. Their unique structures and diverse biological actions make them promising candidates for drug discovery and medicinal applications. The review encompasses their occurrence, distribution, structural features, and biological activities, providing invaluable insights for future pharmacological explorations and research.

Effects of Pieris japonica (Ericaceae) dominance on cool temperate forest altered-understory environments and soil microbiomes in Southern Japan

The number of plants unpalatable to deer increases with increasing deer numbers. In the Kyushu Mountain area of Southern Japan, Pieris japonica (Ericaceae), an unpalatable shrub, has become the monodominant vegetation under evergreen conifer and deciduous broad-leaved tree stands. The monodominance of unpalatable plants in the understory has potential advantages and drawbacks; however, the effects of Pieris dominance are not well understood. To assess the effects of P. japonica dominances on forest environments and ecosystems, we investigated understory environments and soil microbiomes in Pieris-dominant sites. Under the deciduous broad-leaved trees, Pieris dominance leads to considerable Pieris leaf litter and humus weights and low soil bulk density and canopy openness. In the soil fungal community and fungal functional groups, the relative abundance of symbiotrophic fungi, particularly ectomycorrhizal fungi in Pieris-dominant sites were lower than in other-vegetation understory sites and saprotrophic fungi vice versa. Because few seedlings and saplings were found under Pieris shrubs, Pieris dominance in the understory might exclude other plant species. The results of this study will contribute to the Pieris population and forest management following deer overgrazing.

Novel Fermentation Strategies of Strawberry Tree Arbutus unedo Fruits to Obtain High Nutritional Value Products

The strawberry tree (Arbustus unedo) is a medicinal plant and an important source of biocompounds, potentially useful for pharmaceutical and chemical applications to prevent or treat several human diseases. The strawberry tree fruits have usually been used to produce traditional products such as jams and jellies and to obtain fermented alcoholic drinks, representing the most valuable derivative products. Other fermented products are potentially interesting for their nutritional value; however, the fermentation process needs to be controlled and standardized to obtain high-quality products/ingredients. In this work, we investigated two different fermentative procedures, using strawberry tree whole fruit and fruit paste as matrices inoculated with a selected starter strain of Saccharomyces cerevisiae LI 180-7. The physical, chemical, microbiological and nutritional properties of fermented products were evaluated, as well as their antioxidant activity. The new obtained fermented products are enriched in organic acids (acetic acid varied from 39.58 and 57.21 mg/g DW and lactic acid from 85.33 to 114.1 mg/g DW) and have better nutritional traits showing a higher amount of total polyphenols (phenolic acids, flavonoids and anthocyanins) that ranged from 1852 mg GAE/100 g DW to 2682 mg GAE/100 g DW. Also, the amount of isoprenoid increased ranging from 155.5 μg/g DW to 164.61 μg/g DW. In this regard, the most promising strategy seemed to be the fermentation of the fruit paste preparation; while the extract of fermented whole fruits showed the most powerful antioxidant activity. Finally, a preliminary attempt to produce a food prototype enriched in fermented strawberry tree fruits suggested the whole fruit fermented sample as the most promising from a preliminary sensory analysis.

Vascular plants and mosses as bioindicators of variability of the coastal pine forest (Empetro nigri-Pinetum)

Empetro nigri-Pinetum is a unique sea coast plant community developing along the Baltic Sea from Germany to Lithuania. Our detailed field research of bryophytes and vascular plants has highlighted the regional diversity of the Empetro nigri-Pinetum typicum plant community throughout its range in Central Europe. Our study indicated that vascular plants and mosses effectively discriminate against the described phytocoenoses, thus it was possible to distinguish three variants of the coastal forest: Calluna-Deschampsia (from Germany), Vaccinium vitis-idaea (from Poland) and Melampyrum-Deschampsia (from Lithuania). Redundancy analysis indicated that the division is related to the habitat conditions of the analyzed areas, with humidity having the greatest impact on this differentiation. Kohonen's artificial neural network (i.e. self-organising map, SOM) confirmed the heterogeneous nature of the studied phytocenoses, and combined with the IndVal index enabled identification of indicator species for respective studied patches: Deschampsia flexuosa for Calluna-Deschampsia group; Aulacomnium palustre, Calluna vulgaris, Carex nigra, Dicranum polysetum, Erica tetralix, Oxycoccus palustris, Sphagnum capillifolium, Vaccinium uliginosum and Vaccinium vitis-idaea for Vaccinium vitis-idaea group; and young specimens of Betula pendula, Lycopodium annotinum, Melampyrum pratense and Orthilia secunda for Melampyrum-Deschampsia group. Thereby, our study showed that individual groups of species can be very good bioindicators for each of the studied phytocoenoses.

Flower orientation and corolla length as reproductive barriers in the pollinator-driven divergence of Erica shannonea and Erica ampullacea

A variety of reproductive barriers can enable reproductive isolation and stable coexistence of plant species. Differing floral traits might play an important role in reproductive isolation imposed by pollinators. Such shifts in pollinator use have been hypothesized to contribute to the radiation of Erica (Ericaceae) in the Cape Floristic Region, South Africa. The sister species Erica shannonea and Erica ampullacea co-occur and overlap in flowering phenology. Both have unscented long-tubed flowers consistent with adaptations for pollination by long-proboscid flies (LPFs), but differences in flower orientation and corolla tube length are indicative of a shift in pollinator species. We conducted controlled pollination experiments and pollinator observations to determine the breeding system and pollinators of the two species. Both species are self-incompatible and require pollinator visits for seed production, suggesting that pollinators could strongly influence flower evolution. The horizontally orientated flowers of E. shannonea were found to be pollinated by Philoliche rostrata (Tabanidae), which has a long, fixed forward-pointing proboscis, while the vertically upright orientated flowers of E. ampullacea were found to be pollinated by Prosoeca westermanni (Nemestrinidae), which has a shorter proboscis that can swivel downwards. The nemestrinid fly's proboscis is too short to access the nectar in the relative long-tubed flowers of E. shannonea and the tabanid fly's proboscis cannot swivel down to access the upright flowers of E. ampullacea. Consequently, these traits are likely to act as reproductive barriers between the two Erica species and thereby might have contributed to speciation and enable stable coexistence.

Characterization of the Complete Chloroplast Genome of Gaultheria nummularioides D.Don 1825 (Ericaceae)

Gaultheria nummularioides D.Don 1825 (Ericaceae) is a traditional Chinese medicinal plant used to treat rheumatoid arthritis. The complete chloroplast genome of G. nummularioides has been sequenced and assembled. The genome is 176,207 bp in total with one large single copy (LSC: 107,726 bp), one small single copy (SSC: 3,389 bp), and two inverted repeat regions (IRa and IRb; each 32,546 bp). The chloroplast genome encoded a total of 110 unique genes; the GC content of these genes is 36.6%. The results based on phylogenetic analysis of the complete chloroplast genome suggests that G. nummularioides diverged later than G. praticola, the sister relationship between G. nummularioides and the clade comprising G. fragrantissima Wall. 1820 and G. hookeri C.B. Clarke 1882 was strongly supported. This study provides additional information on the genetic diversity of G. nummularioides, its closely related taxa, and further exploration of chloroplast genomes in the Ericaceae family.

The evolution of Ericaceae flowers and their pollination syndromes at a global scale

PREMISE

Floral evolution in large clades is difficult to study not only because of the number of species involved, but also because they often are geographically widespread and include a diversity of outcrossing pollination systems. The cosmopolitan blueberry family (Ericaceae) is one such example, most notably pollinated by bees and multiple clades of nectarivorous birds.

METHODS

We combined data on floral traits, pollination ecology, and geography with a comprehensive phylogeny to examine the structuring of floral diversity across pollination systems and continents. We focused on ornithophilous systems to test the hypothesis that some Old World Ericaceae were pollinated by now-extinct hummingbirds.

RESULTS

Despite some support for floral differentiation at a continental scale, we found a large amount of variability within and among landmasses, due to both phylogenetic conservatism and parallel evolution. We found support for floral differentiation in anther and corolla traits across pollination systems, including among different ornithophilous systems. Corolla traits show inconclusive evidence that some Old World Ericaceae were pollinated by hummingbirds, while anther traits show stronger evidence. Some major shifts in floral traits are associated with changes in pollination system, but shifts within bee systems are likely also important.

CONCLUSIONS

Studying the floral evolution of large, morphologically diverse, and widespread clades is feasible. We demonstrate that continent-specific radiations have led to widespread parallel evolution of floral morphology. We show that traits outside of the perianth may hold important clues to the ecological history of lineages.

Ice holes microrefugia harbor genetically and functionally distinct populations of Vaccinium vitis-idaea (Ericaceae)

In the mountain terrain, ice holes are little depressions between rock boulders that are characterized by the exit of cold air able to cool down the rock surface even in summer. This cold air creates cold microrefugia in warmer surroundings that preserve plant species probably over thousands of years under extra-zonal climatic conditions. We hypothesized that ice hole populations of the model species Vaccinium vitis-idaea (Ericaceae) show genetic differentiation from nearby zonal subalpine populations, and high functional trait distinctiveness, in agreement with genetic patterns. We genotyped almost 30,000 single nucleotide polymorphisms using restriction site-associated DNA sequencing and measured eight functional traits indicative of individual performance and ecological strategies. Genetic results showed high differentiation among the six populations suggesting isolation. On siliceous bedrock, ice hole individuals exhibited higher levels of admixture than those from subalpine populations which could have experienced more bottlenecks during demographic fluctuations related to glacial cycles. Ice hole and subalpine calcareous populations clearly separated from siliceous populations, indicating a possible effect of bedrock in shaping genetic patterns. Trait analysis reflected the bedrock effect on populations' differentiation. The significant correlation between trait and genetic distances suggests the genetic contribution in shaping intraspecific functional differentiation. In conclusion, extra-zonal populations reveal a prominent genetic and phenotypic differentiation determined by history and ecological contingency. Therefore, microrefugia populations can contribute to the overall variability of the species and lead to intraspecific-driven responses to upcoming environmental changes.

In vitro, in vivo and in silico evaluation of analgesic, anti-inflammatory, and anti-pyretic activity of salicylate rich fraction from Gaultheria trichophylla Royle (Ericaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal properties of Gaultheria have been used in traditional medicine to treat pain and inflammation.

AIM OF THE STUDY

Hence, the purpose of this study was to evaluate the analgesic, antipyretic, and anti-inflammatory properties of Gaultheria trichophylla Royle extract and salicylate-rich fraction in vivo, in vitro, and in silico.

MATERIALS AND METHODS

In vivo analgesic, antipyretic, and anti-inflammatory of extract and a salicylate-rich fraction (at doses of 100, 200, 300, and 150 mg/kg) were assessed using healthy albino mice employing acetic acid-induced writhing, tail immersion test, carrageenan-induced inflammation, and croton oil-induced edema. For in vitro testing of extracts COX and LOX enzyme inhibition assays were used. Molecular docking studies were conducted for in silico testing of the inhibitory activity of the dominant compound Gaultherin against COX and LOX.

RESULTS

G-EXT 200 and 300 and G-SAL 150 mg/kg reduced pyrexia significantly (P < 0.05 and P < 0.01). G-EXT-200, 300, and G-SAL 150 reduce the writing to a significant level (p > 0.05, p < 0.01). G-EXT 200 and 300 and G-SAL 150 mg/kg doses the analgesic effect was significant (p > 0.05, p > 0.01) and was comparable to tramadol. G-EXT 100 200, 300 mg/kg showed 43.8%, 47.94% and 56% respectively. G-SAL 150 mg, rich in salicylates, showed maximum inhibition of 65.75% next to standard drug diclofenac with 76.7% inhibition. G-EXT 100 and 200 mg/kg dose showed significant (p < 0.05) reduction in ear edema. With 300 mg/kg dose the effect was more (61.89%, p < 0.01). The salicylate-rich fraction G-SAL and Celecoxib showed an almost similar effect (p < 0.01). Significance inhibition was shown in the COX-2 test (G-EXT 39.70 and G-SAL 77.20 IC50 μg/ml) and in the 5-LOX test (G-EXT 28.3 and G-SAL 39.70 IC50 μg/ml). The preliminary in silico results suggest that the investigated compound showed excellent inhibitory activity against COX and LOX enzymes as evident from the free binding energy. Molecular docking revealed that Gaultherin binds well in the COX and LOX enzyme catalytic region.

CONCLUSION

The extract and salicylate-rich fraction obtained from G. trichophylla showed significant analgesic, anti-inflammatory, and antipyretic effects in vivo, in vitro, and in silico assays that support its use in traditional medicine.

Monotropastrum kirishimense (Ericaceae), a new mycoheterotrophic plant from Japan based on multifaceted evidence

Due to their reduced morphology, non-photosynthetic plants have been one of the most challenging groups to delimit to species level. The mycoheterotrophic genus Monotropastrum, with the monotypic species M. humile, has been a particularly taxonomically challenging group, owing to its highly reduced vegetative and root morphology. Using integrative species delimitation, we have focused on Japanese Monotropastrum, with a special focus on an unknown taxon with rosy pink petals and sepals. We investigated its flowering phenology, morphology, molecular identity, and associated fungi. Detailed morphological investigation has indicated that it can be distinguished from M. humile by its rosy pink tepals and sepals that are generally more numerous, elliptic, and constantly appressed to the petals throughout its flowering period, and by its obscure root balls that are unified with the surrounding soil, with root tips that hardly protrude. Based on genome-wide single-nucleotide polymorphisms, molecular data has provided clear genetic differentiation between this unknown taxon and M. humile. Monotropastrum humile and this taxon are associated with different Russula lineages, even when they are sympatric. Based on this multifaceted evidence, we describe this unknown taxon as the new species M. kirishimense. Assortative mating resulting from phenological differences has likely contributed to the persistent sympatry between these two species, with distinct mycorrhizal specificity.

Betula alba Bark Extract and Empetrum nigrum Fruit Juice, a Natural Alternative to Niacinamide for Skin Barrier Benefits

The Scandinavian region is home to a unique biome with endemic plant species. The aim of this study was to explore this natural diversity and identify plant extracts providing positive skin barrier effects. Six plant extracts were identified as starting material. Following biochemical screening, two candidates outperformed the rest: Betula alba (BA) and Empetrum nigrum (EN). Quantitative PCR analysis showed that BA and EN upregulated barrier genes, when used individually and in combination. Betula alba increased AQP3 and OCLN protein expression, something niacinamide was incapable of. Additionally, the skin barrier was strengthened, evidenced by inhibition of KLK5 and hyaluronidase and showed strong antioxidant and anti-inflammatory activity through DPPH and COX2 inhibition, respectively. A first split-face clinical study was conducted using the combination of extracts versus placebo. There was a significantly better skin restructuring effect and corneocyte cohesion on the side treated with combined extracts. A second split-face clinical study assessed the combined extracts versus 3% niacinamide. Significant variations in skin hydration and TEWL were observed in favor of the extract treated side. In conclusion, we identified a natural alternative to niacinamide for improving skin barrier health, in Scandinavian plant extracts, which yield strong performance, but at a lower concentration.

Fertility Effects on Blueberry Gall Midge (Diptera: Cecidomyiidae) in Wild Blueberry (Vaccinium angustifolium; Ericales: Ericaceae)

Blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) is a pest in American cranberry, Vaccinium macrocarpon Aiton (Ericales: Ericaceae) and wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae), and has been observed in areas of high soil and foliar nutrient levels. New management strategies, including fertilization, will need to be altered to sustain wild blueberry production under climate change and, in turn, may impact the occurrence of this pest. The purpose of this study was to measure the effect of diammonium phosphate (DAP) fertilizer application on density of infested stems and the combined effects of fertilizer application with and without infestation on wild blueberry systems. This study was conducted at two field sites in Jonesboro and Washington, ME during 2020 and 2021. Despite increases in habitat availability (blueberry cover) for the gall midge and greater infestation density, wild blueberry production benefited from DAP application. This was shown in the number of buds per stem at both sites, as well as in stem height, flowers, green fruit, blue fruit per stem, and total yield at the Washington site. Foliar nitrogen and phosphorus levels had a significant positive linear relationship with infestation density. Growers applying fertilizers should monitor blueberry gall midge field infestation levels due to our findings that DAP fertilizer impacted infestation density and the interaction of DAP fertilizer with infestation impacted wild blueberry production.

Isolation and identification of Arbutus unedo L. fungi endophytes and biological control of Phytophthora cinnamomi in vitro

Strawberry tree (Arbutus unedo, Ericaceae) is an evergreen tree with a circum-Mediterranean distribution. It has a great ecological and economic importance as a source of bioactive compounds with industrial applications and for fruit production. This study aims to characterize the fungi microbiome of this forestry species in order to develop biological control strategies in the increasing orchard production area. For this purpose, fungi endophytes were isolated from wild strawberry tree plants, and a molecular identification was carried out. In vitro assays were carried out to evaluate and characterize the antagonism of some endophytes. Among the several fungi endophytes isolated from strawberry tree (a total of 53 from 20 genera), a Trichoderma atroviride strain proved to have antagonism effect against several phytopathogens, including Alternaria alternata, Botrytis cinerea, Glomerella cingulata, and Mycosphaerella aurantia. This antagonism was particularly effective against Phytophthora cinnamomi, causing a reduction in growth of about 80% on this invasive oomycete. An enzymatic assay revealed the production of several enzymes by T. atroviride, such as cellulases, chitinases, glucosidases, alkaline phosphatases, and proteases, which is one of the several mechanisms known to be involved on Trichoderma biological control ability. The enzymatic activity, in particular that of cell wall-degrading enzymes, was accentuated when in a dual culture with P. cinnamomi. The production of serine proteases, aspartyl proteases, metalloproteases, and cysteine proteases was also detected in an experiment carried out in liquid medium, suggesting the involvement of these proteases on Trichoderma mycoparasitism mechanisms. Finally, in a three-way interaction with in vitro strawberry tree plants, the T. atroviride strain identified on this study (Au50) was able to protect the plants against P. cinnamomi, thus proving its potential as a biological control agent.

Automatic Identification of Myeloperoxidase Natural Inhibitors in Plant Extracts

The aim of this study is the development of an automated method for myeloperoxidase activity evaluation and its application in testing the inhibitory action of different plant extracts on the activity of the enzyme. This enzyme has its concentration increased in inflammatory and infectious processes, so it is a possible target to limit these processes. Therefore, an automatic sequential in-jection analysis (SIA) system was optimized and demonstrated that it is possible to obtain results with satisfactory accuracy and precision. With the developed method, plant extracts were studied, as promising candidates for MPO inhibition. In the group of selected plant extracts, IC50 values from 0.029 ± 0.002 mg/mL to 35.4 ± 3.5 mg/mL were obtained. Arbutus unedo L. proved to be the most inhibitory extract for MPO based on its phenolic compound content. The coupling of an automatic SIA method to MPO inhibition assays is a good alternative to other conventional methods, due to its simplicity and speed. This work also supports the pharmacological use of these species that inhibit MPO, and exhibit activity that may be related to the treatment of infection and inflammation.

Identification of Lagopus muta japonica food plant resources in the Northern Japan Alps using DNA metabarcoding

DNA metabarcoding was employed to identify plant-derived food resources for the Japanese rock ptarmigan (Lagopus muta japonica), which is registered as a natural living monument in Japan, in the Northern Japanese Alps in Toyama Prefecture, Japan, in July to October, 2015-2018. DNA metabarcoding using high-throughput sequencing (HTS) of rbcL and ITS2 sequences from alpine plants found in ptarmigan fecal samples collected in the study area. The obtained sequences were analyzed using a combination of a constructed local database and the National Center for Biotechnology Information (NCBI) database, revealed that a total of 53 plant taxa were food plant resources for ptarmigans. Of these plant taxa, 49 could be assigned to species (92.5%), three to genus (5.7%), and one to family (1.9%). Of the 23 plant families identified from the 105 fecal samples collected, the dominant families throughout all collection periods were Ericaceae (99.0% of 105 fecal samples), followed by Rosaceae (42.9%), Apiaceae (35.2%), and Poaceae (21.0%). In all of the fecal samples examined, the most frequently encountered plant species were Vaccinium ovalifolium var. ovalifolium (69.5%), followed by Empetrum nigrum var. japonicum (68.6%), Kalmia procumbens (42.9%), Tilingia ajanensis (34.3%) and V. uliginosum var. japonicum (34.3%). A rarefaction analysis for each collection period in the study revealed that the food plant resources found in the study area ranged from a minimum of 87.0% in July to a maximum of 97.5% in September, and that 96.4% of the food plant taxa were found throughout the study period. The findings showed that DNA metabarcoding using HTS to construct a local database of rbcL and ITS2 sequences in conjunction with rbcL and ITS2 sequences deposited at the NCBI, as well as rarefaction analysis, are well suited to identifying the dominant food plants in the diet of Japanese rock ptarmigans. In the windswept alpine dwarf shrub community found in the study area, dominant taxa in the Ericaceae family were the major food plant s for Japanese rock ptarmigans from July to October. This plant community therefore needs to be conserved in order to protect the food resources of Japanese rock ptarmigans in the region.

Metals in Calluna vulgaris, Empetrum nigrum, Festuca vivipara and Thymus praecox ssp. arcticus in the geothermal areas of Iceland

This investigation was conducted to identify the content of metals in Calluna vulgaris (family Ericaceae), Empetrum nigrum (family Ericaceae), Festuca vivipara (family Poaceae) and Thymus praecox subsp. arcticus (family Lamiaceae), as well as in the soils where they were growing in eight geothermal heathlands in Iceland. Investigation into the vegetation of geothermal areas is crucial and may contribute to their proper protection in the future and bring more understanding under what conditions the plants respond to an ecologically more extreme situation. Plants from geothermally active sites were enriched with metals as compared to the same species from non-geothermal control sites (at an average from about 150 m from geothermal activity). The enriched metals consisted of Cd, Co, Cu, Fe and Ni in C. vulgaris; Cd, Mn and Ti in E. nigrum; Hg and Pb in F. vivipara; and Cd, Fe and Hg in T. praecox. Notably, C. vulgaris, E. nigrum, F. vivipara and T. praecox had remarkably high concentrations of Ti at levels typical of toxicity thresholds. Cd and Pb (except for C. vulgaris and F. vivipara) were not accumulated in the shoots of geothermal plants. C. vulgaris from geothermal and control sites was characterised by the highest bioaccumulation factor (BF) of Ti and Mn; E. nigrum and F. vivipara by the highest BF of Ti and Cr; and T. praecox by the highest BF of Ti and Zn compared to the other elements. In comparison with the other examined species, F. vivipara from geothermal sites had the highest concentration of Ti in above-ground parts at any concentration of plant-available Ti in soil.

Largely invariant communities of bacterial endophytes in the nonphotosynthetic mycoheterotrophic plant Pterospora andromedea

PREMISE

Mycoheterotrophic plants rely on fungi to obtain their carbon requirements. Recent experiments demonstrated the presence of endophytic bacteria associated with mycoheterotrophs. Although mycoheterotrophs show high specificity for their fungal partners, it is not known whether they also show high specificity for associated bacteria or whether the bacteria have a definite function in the symbiosis.

METHODS

Two 16S rRNA sequencing experiments were designed to explore endophytic microbial community composition and function in root ball fractions of the mycoheterotroph Pterospora andromedea (Ericaceae), and rhizosphere soil and control soil 5 m away from each plant. One experiment compared microbial assemblages in fractions of six plants to those in rhizosphere and control soil samples. Another experiment documented bacterial endophyte diversity in root balls of 97 plants from across North America.

RESULTS

Soil samples were similar in bacterial community structure but were significantly more diverse and less consistently structured than were bacterial communities within root balls. The proportion of endophytic bacterial species varied slightly but not their community composition despite differences in P. andromedea lineage, geography, conifer species, and fungi. Predictive metagenomic profiling of the endophytes in P. andromedea-only root ball fractions showed many of the bacterial endophytes likely function in N-metabolism and N-fixation.

CONCLUSIONS

Our results document a consistent and largely invariant community of endophytic bacteria in P. andromedea across biotic and abiotic environmental conditions at a continental scale. It is unknown what role these bacteria may play in the quad-partite symbiotic network centered on P. andromedea; however, the predictive metagenomic profiling suggests a possible function in N-metabolism or N-fixation. Discovery of a ubiquitous community of endophytic bacteria with a putative function centered on N-metabolism or N-fixation could have a previously unrecognized impact on understanding of mycoheterotroph ecophysiology.

Corolla stickiness prevents nectar robbing in Erica

Floral stickiness is a rare trait with unknown function, but it is common in the mega-diverse Cape genus Erica (Ericaceae). This study investigated the role of stickiness measured as adhesive strength in Erica as protection against nectar robbing and its correlation with floral traits. We compared the incidence of nectar robbing in flowers of the same species with or without experimentally added stickiness, and amongst communities of co-occurring species with flowers differing in stickiness. Additionally, we tested the relationship between stickiness and pollination syndrome, corolla shape, corolla length and sepal-corolla ratio across the whole genus. Stickiness was correlated with lower floral damage rates within and between species, indicating it functions as an anti-nectar robbing trait. Across the genus Erica, stickiness is most strongly correlated with bird and long-proboscid fly pollination, presumably because of their larger nectar rewards. Stickiness was also correlated with floral traits that are often associated with high risk of being damaged by nectar robbers: narrow-mouthed corollas, long corollas and shorter sepals. These results show that corolla stickiness defends Erica flowers against nectar robbing and thereby potentially improves fitness.

Relationships between topographic factors, soil and plant communities in a dry Afromontane forest patches of Northwestern Ethiopia

Plant community types are influenced by topographic factors, the physical and chemical properties of soil. Therefore, the study was carried out to investigate the relationships of soil and topographic factors on the distribution of species and plant community formation of the Dega Damot district in Northwestern Ethiopia. Vegetation and environmental data were collected from 86 plots (900 m²). Agglomerative hierarchical cluster analysis and redundancy analysis (RDA) with R software were used to identify plant communities and analyze the relationship between plant community types and environmental variables. Five plant community types were identified: Erica arborea-Osyris quadripartita, Discopodium penninervium-Echinops pappii, Olea europaea -Scolopia theifolia, Euphorbia abyssinica-Prunus africana, Dodonaea anguistifolia-Acokanthera schimperi. The RDA result showed that the variation of species distribution and plant community formation were significantly related to altitude, organic matter, moisture content, slope, sand, pH, EC, total nitrogen and phosphorus. Our results suggest that the variation of plant communities (Community 1, 2, 3, and 4) were closely related to environmental factors, including altitude, moisture content, OM, slope, sand, pH, EC, soil nitrogen, and phosphorus, among which altitude was the most important one. However, all the measured environmental variables are not correlated to Dodonaea anguistifolia-Acokanthera schimperi community type. Therefore, it can be concluded that some other environmental variables may influence the species composition, which is needed to be further investigated.

Genetic structure of a widespread alpine shrub Rhododendron aureum (Ericaceae) across East Asia

The vast territory of East Asia, including southwestern Beringia, is considered to have been almost ice free during the Pleistocene. Cold-resistant flora may have persisted in this region expanding or contracting its range during the climate cooling. Only a few plant genera have been studied with a sampling area across their entire geographic range in East Asia; therefore, the understanding of the biogeographic history of alpine flora in this region remains limited. In the present study, genetic variation and population structure in 21 populations of the alpine shrub Rhododendron aureum across its range in East Asia were assessed using 18 microsatellite loci. Phylogenetic analyses revealed three main genetic groups: Siberia, Northeast, and North Pacific. According to the geographical pattern of genetic diversity, the North Pacific group includes populations from Kamchatka, south of Russian Far East, and territories close to central Japan. This group is the most diverse and likely diverged earlier than the Siberia and Northeast groups. Ecological niche modeling predicts range expansion of this species during the period of cooling and, together with demographic history, suggests that the divergence between the three main genetic groups predated the Last Glacial Maximum. Similar to other cold-resistant species such as Larix sibirica and Juniperus communis, the pattern of genetic diversity of R. aureum supports the survival of the species at high latitudes during the Pleistocene with limited contribution of the southern populations to expansion of the species range to the Northeast region and Siberia.

Ericoid mycorrhizal symbiosis: theoretical background and methods for its comprehensive investigation

Despite decades of intensive research (especially from 1970s to 1990s), the ericoid mycorrhizal (ErM) hair root is still largely terra incognita and this simplified guide is intended to revive and promote the study of its mycobiota. Basic theoretical knowledge on the ErM symbiosis is summarized, followed by practical advices on Ericaceae root sample collection and handling, microscopic observations and photo-documentation of root fungal colonization, mycobiont isolation, maintenance and identification and resynthesis experiments with ericoid plants. The necessity of a proper selection of the root material and its surface sterilization prior to mycobiont isolation is stressed, together with the need of including suitable control treatments in inoculation experiments. The culture-dependent approach employing plating of single short (~ 2 mm) hair root segments on nutrient media is substantiated as a useful tool for characterization of Ericaceae root-associated fungal communities; it targets living mycelium and provides metabolically active cultures that can be used in physiological experiments and taxonomic studies, thus providing essential reference material for culture-independent approaches. On the other hand, it is stressed that not every mycobiont isolated from an ericoid hair root necessarily represent an ErM fungus. Likewise, not every intracellular hyphal coil formed in the Ericaceae rhizodermis necessarily represents the ErM symbiosis. Taxonomy of the most important ericoid mycobionts is updated, mutualism in the ErM symbiosis is briefly discussed from the mycobiont perspective, and some interesting lines of possible future research are highlighted.

Synthesis and ultrastructural observation of arbutoid mycorrhizae of black truffles (Tuber melanosporum and T. aestivum)

Arbutus unedo (the strawberry tree) is a Mediterranean shrub which forms arbutoid mycorrhizae with a variety of Asco- and Basidiomycetes. After the discovery of the mycorrhizal symbiosis between A. unedo and Tuber borchii, in this study, arbutoid mycorrhizae were synthetized in greenhouse with Tuber aestivum and Tuber melanosporum. Six months after inoculation, both species colonized the roots of all inoculated A. unedo seedlings, but mature mycorrhizae were only observed after 12 months. Ultrastructure analysis of Tuber arbutoid mycorrhizae was described for the first time, showing, as observed in typical endosymbiosis, a rearrangement of host cells and the creation of an interface compartment with both truffle species. Immunolabelling experiments suggested that pectins are not present in the interface matrix surrounding the intracellular hyphae. Thus, the ability to establish symbiosis with A. unedo seems to be a common feature in the genus Tuber, opening up the possibility to use this plant for mycorrhization with valuable truffles. This could represent an important economic opportunity in Mediterranean areas by combining the production of truffles, edible fruits and valued honey.

Shoot-level flammability across the Dracophyllum (Ericaceae) phylogeny: evidence for flammability being an emergent property in a land with little fire

Plant flammability varies across species, but the evolutionary basis for this variation is not well understood. Phylogenetic analysis of interspecific variation in flammability can provide insights into the evolution of plant flammability. We measured four components of flammability (ignitability, sustainability, combustibility and consumability) to assess the shoot-level flammability of 21 species of Dracophyllum (Ericaceae). Using a macroevolutionary approach, we explored phylogenetic patterns of variation in shoot-level flammability. Shoot-level flammability varied widely in Dracophyllum. Species in the subgenus Oreothamnus had higher flammability and smaller leaves than those in the subgenus Dracophyllum. Shoot flammability (ignitability, combustibility and consumability) and leaf length showed phylogenetic conservatism across genus Dracophyllum, but exhibited lability among some closely related species, such as D. menziesii and D. fiordense. Shoot flammability of Dracophyllum species was negatively correlated with leaf length and shoot moisture content, but had no relationship with the geographic distribution of Dracophyllum species. Shoot-level flammability varied widely in the genus Dracophyllum, but showed phylogenetic conservatism. The higher flammability of the subgenus Oreothamnus may be an incidental or emergent property as a result of the evolution of flammability-related traits, such as smaller leaves, which were selected for other functions and incidentally changed flammability.

Evidence for newly discovered albino mutants in a pyroloid: implication for the nutritional mode in the genus Pyrola

PREMISE

Difficulties in comparing extremely divergent features in fully mycoheterotrophic plants with those in closely related chlorophyllous plants have complicated attempts to reveal the evolutionary patterns and processes of fully mycoheterotrophic plants. Albino mutants of partially mycoheterotrophic plants, generally observed in Orchidaceae, have provided an ideal model for investigating the evolution of mycoheterotrophy within similar genetic backgrounds. In 2018, we found a putative albino population of Pyrola (Ericaceae). Here we aimed to reveal the identity of the albino pyroloid and confirm its fully mycoheterotrophic status.

METHODS

To reveal the putative albino pyroloid's identity, we examined its morphology and sequenced its chloroplast DNA. In addition, we assessed the trophic status of the putative albino pyroloid by analyzing chlorophyll fluorescence, chlorophyll concentration, and natural 13 C and 15 N abundances.

RESULTS

We identified albino individuals as P. japonica-otherwise a partially mycoheterotrophic species. We confirmed their albino status by their considerably lower chlorophyll fluorescence and concentrations than those of sympatrically occurring chlorophyllous plants. 13 C abundance in the albino individuals was significantly higher than in the green individuals of P. japonica.

CONCLUSIONS

This first report of albino mutants from partially mycoheterotrophic species in angiosperms other than orchids will play a valuable role in further studies focused on mycoheterotrophy. For instance, their δ13 C and δ15 N values represent a reference for fully mycoheterotrophic plants in Pyrola. Our findings also indicate the strong dependence of some leafy Pyrola species on fungal C during their entire life cycle.

Modularity and evolution of flower shape: the role of function, development, and spandrels in Erica

Flowers have been hypothesized to contain either modules of attraction and reproduction, functional modules (pollination-effecting parts) or developmental modules (organ-specific). Do pollination specialization and syndromes influence floral modularity? In order to test these hypotheses and answer this question, we focused on the genus Erica: we gathered 3D data from flowers of 19 species with diverse syndromes via computed tomography, and for the first time tested the above-mentioned hypotheses via 3D geometric morphometrics. To provide an evolutionary framework for our results, we tested the evolutionary mode of floral shape, size and integration under the syndromes regime, and - for the first time - reconstructed the high-dimensional floral shape of their most recent common ancestor. We demonstrate that the modularity of the 3D shape of generalist flowers depends on development and that of specialists is linked to function: modules of pollen deposition and receipt in bird syndrome, and access-restriction to the floral reward in long-proboscid fly syndrome. Only size and shape principal component 1 showed multiple-optima selection, suggesting that they were co-opted during evolution to adapt flowers to novel pollinators. Whole floral shape followed an Ornstein-Uhlenbeck (selection-driven) evolutionary model, and differentiated relatively late. Flower shape modularity thus crucially depends on pollinator specialization and syndrome.

Genotype-specific effects of ericoid mycorrhizae on floral traits and reproduction in Vaccinium corymbosum

PREMISE

Most plants interact with mycorrhizal fungi and animal pollinators simultaneously. Yet, whether mycorrhizae affect traits important to pollination remains poorly understood and may depend on the match between host and fungal genotypes. Here, we examined how ericoid mycorrhizal fungi affected flowering phenology, floral traits, and reproductive success, among eight genotypes of highbush blueberry, Vaccinium corymbosum (Ericaceae). We asked three overarching questions: (1) Do genotypes differ in response to inoculation? (2) How does inoculation affect floral and flowering traits? (3) Are inoculated plants more attractive to pollinators and less pollen limited than non-inoculated plants of the same genotype?

METHODS

To examine these questions, we experimentally inoculated plants with ericoid mycorrhizal fungi, grew the plants in the field, and measured flowering and floral traits over 2 years. In year 2, we conducted a hand-pollination experiment to test whether plants differed in pollen limitation.

RESULTS

Inoculated plants had significantly higher levels of colonization for some genotypes, and there were significant floral trait changes in inoculated plants for some genotypes as well. On average, inoculated plants produced significantly larger floral displays, more fruits per inflorescence, and heavier fruits with lower sugar content, than non-inoculated, control plants. Hand pollination enhanced the production of fruits, and fruit mass, for non-inoculated plants but not for those that were inoculated.

CONCLUSIONS

Our results demonstrate that inoculation with ericoid mycorrhizal fungi enhanced flowering and altered investment in reproduction in genotype-specific ways. These findings underscore the importance of examining belowground symbionts and genotype-specific responses in their hosts to fully understand the drivers of aboveground interactions.

Spotted-Wing Drosophila (Diptera: Drosophilidae) Adult Movement, Activity, and Oviposition Behavior in Maine Wild Blueberry (Vaccinium angustifolium; Ericales: Ericaceae)

Over a period of 5 yr (2012-2016), we conducted laboratory and field studies on activity, movement, and response to trap placement of adult Drosophila suzukii (Matsumura) in wild blueberry, Vaccinium angustifolium Aiton, fields in Maine. When measuring temporal patterns in fruit infestation, we found that D. suzukii females are most active in the morning and that they are 10 times more likely to lay eggs in blueberries at the top of the plant canopy compared with berries located in the lower part of the bush. Flies were found to be more abundant in fruit-bearing (crop) fields compared with pruned (vegetative) fields based on trap capture of adults. They are also most abundant along edges of fields compared with interiors. Trap efficiency is significantly better in traps 1.2 m above the ground and above the crop canopy of this low-growing crop plant than within the crop canopy. Three experiments involving the marking of laboratory-reared flies with fluorescent marker, their release, and capture with traps along a grid in fields suggest that: 1) fluorescent markers do not affect the distance moved of marked flies, 2) dispersal rates are not different between sexes, 3) there is little difference in the dispersal pattern through pruned fields and fruit-bearing fields, and 4) flies disperse at a low rate of 0.1-30 m per day, with an average of 5 m per day, but that long-distance dispersal over 1-2 km is feasible based on statistical model extrapolation.

An approach to determining anthocyanin synthesis enzyme gene expression in an evolutionary context: an example from Erica plukenetii

BACKGROUND AND AIMS

Floral colour in angiosperms can be controlled by variations in the expression of the genes of the anthocyanin pathway. Floral colour shifts influence pollinator specificity. Multiple shifts in floral colour occurred in the diversification of the genus Erica (Ericaceae), from plesiomorphic pink to, for example, red or white flowers. Variation in anthocyanin gene expression and its effects on floral colour in the red-, pink- and white-flowered Erica plukenetii species complex was investigated.

METHODS

Next generation sequencing, reverse transcriptase PCR and real-time reverse transcriptase quantitative PCR were used to quantify anthocyanin gene expression.

KEY RESULTS

Non-homologous mutations causing loss of expression of single genes were found, indicating that the cause was likely to be mutations in transcription factor binding sites upstream of the 5'-untranslated region of the genes, and this was confirmed by sequencing.

CONCLUSIONS

Independent evolution and subsequent loss of expression of anthocyanin genes may have influenced diversification in the E. plukenetii species complex. The approach developed here should find more general application in studies on the role of floral colour shifts in diversification.

Relationships between Tertiary relict and circumboreal woodland floras: a case study in Chimaphila (Ericaceae)

BACKGROUND AND AIMS

Tertiary relict and Arctic/circumboreal distributions are two major patterns of Northern Hemisphere intercontinental disjunctions with very different histories. Each has been well researched, but members of one biome have generally not been incorporated in the biogeographical analyses of the other, and links or transitions between these two biomes have rarely been addressed.

METHODS

Phylogenies of Chimaphila were generated based on cpDNA and nuclear ITS, using Bayesian and maximum likelihood methods. A time-calibrated phylogeny was generated using BEAST. Ancestral area reconstruction was inferred using both statistical dispersal-vicariance analysis and a dispersal-extinction-cladogenesis model.

KEY RESULTS

The Chimaphila crown group was estimated to have originated in the early Miocene. The lineages of C. umbellata diverged early, but its present circumboreal distribution was not achieved until around the middle Pliocene or later. Sister to this is a clade of four species with Tertiary relict distribution. Among these, two expansions occurred from North America to Asia, probably via the Bering Land Bridge, generating its current disjunctions.

CONCLUSIONS

Our data concur with a few other studies, indicating that the circumboreal woodland biome has an older origin than most true Arctic-alpine taxa, having gradually recruited taxa since the early Oligocene. For the origin of Asia-North America disjunctions in Chimaphila, an 'out-of-America' migration was supported. It is not clear in which direction Pyroloideae lineages moved between Tertiary relict disjunctions and Arctic/circumboreal distributions; each biome might have recruited species from the other.

(Ericales: Ericaceae)

Eastern carpenter bees, Xylocopa virginica (L.) (Hymenoptera: Apidae), are among the most abundant native bee visitors to highbush blueberry, Vaccinium corymbosum L., flowers in the northeastern United States, and they sometimes display corolla-slitting behavior to rob nectar. We studied foraging behavior of X. virginica on 14 blueberry cultivars in an experimental planting in Rhode Island, and assessed factors related to slitting frequency, and the effects of slitting on fruit set and blueberry quality. Among 14 cultivars in bloom, an average of 35% (range 16-67%) of flowers were slit in 2017, and 39% (range 20-62%) in 2018. Factors that affected the proportion of corollas slit included cultivar, anther length, flower volume, and number of days in bloom at or above 15°C. Corolla slitting did not affect fruit set. Average weight and percent soluble solids of fruit resulting from slit and non-slit corollas did not differ significantly in two early- ('Bluehaven', 'Earliblue'), two mid- ('Collins', 'Bluecrop'), and two late-season ('Herbert', 'Lateblue') ripening cultivars in 2017. In 2018, average fruit weight and percent soluble solids resulting from slit and non-slit flowers did not differ significantly in most cultivars, but slit corollas resulted in berries with greater mass in two cultivars, 'Bluehaven' and 'Collins'. 'Collins' fruit from non-slit corollas had a significantly higher percentage of soluble solids at maturity than fruit from slit corollas in 2018. Corolla slitting and nectar robbery by X. virginica did not have a significant negative effect on fruit quality under the described growing conditions and pollinator community.

Association Between Density of Foraging Bees and Fruit Set in Commercial Fields of Rabbiteye Blueberries (Ericales: Ericaceae) in Louisiana and Mississippi

Field-scale data on the relationship between pollinator activity and fruit set are scarce for rabbiteye blueberries (Vaccinium virgatum Aiton). We measured the densities of Apis mellifera L. (Hymenoptera: Apidae), Habropoda laboriosa F. (Hymenoptera: Apidae), Bombus Latreille (Hymenoptera: Apidae) spp., and Xylocopa virginica L. (Hymenoptera: Apidae) in 7-21 commercial fields during each of 3 yr in Louisiana and Mississippi. Foraging bees were counted on 10 'Tifblue' bushes per field on 2 d during bloom, and the density of bees per flower was calculated based on the number of flowers open during the counts. Fruit set was measured 30 d after bloom. The impact of foraging activity on fruit set was inconsistent when densities of either all foragers or foragers of individual taxa were considered. Strong associations were observed only in 2001, with fruit set increased by H. laboriosa and Bombus and with a weaker contribution by A. mellifera. Floral robbery by X. virginica had no measurable negative effects. Populations of H. laboriosa were more consistent than those of other bees across sites. Managed colonies of A. mellifera were added at two densities (12.5 or 2.5 colonies per hectare) in seven fields each in 2001. These supplemental bees did not result in greater forager densities or fruit set in stocked fields. The observations show the challenge of field-scale pollination tests but provide an initial framework for rabbiteye blueberry growers to assess the availability of foraging bees early in bloom to help decide whether to add supplemental A. mellifera to try to enhance pollination if populations of non-Apis bees are low.

The Blueberry Gall Midge (Diptera: Cecidomyiidae): A Recent Pest of Wild Blueberry (Vaccinium angustifolium; Ericales: Ericaceae) and Its Impact on Potential Yield

Blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is an emerging pest on wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae). The purpose of this study was to document the population increase of blueberry gall midge on this crop in Maine since its discovery in 2003 until 2018. Dasineura oxycoccana appears to have three generations during the prune cycle in Maine wild blueberry, although this may vary among years. Prune fields have higher infestation rates than crop fields, most likely due to the greater abundance of susceptible leaf tissue. Production system does affect infestation rates. Fields managed under a high input system exhibit lower gall midge infestation than low or medium input fields. Field infestation rates in organic fields were intermediate to high input and low and medium input fields. In seven trials conducted between 2010 and 2017, D. oxycoccana infestation of stems resulted in significantly fewer flower-bud clusters developed at the end of the prune year in four of seven trials and significantly fewer viable flowers during bloom in the crop year in four of seven trials. Two of the seven trials resulted in significantly more flowers on infested stems than noninfested stems, evidence that in some years D. oxycoccana infestation may stimulate flower-bud production, resulting in an increase in potential yield. We provide an optimal sampling plan for D. oxycoccana infestation sampling and economic thresholds for three levels of production (yield levels) and three expected prices that growers might receive.

The importance of fire season when managing threatened plant species: A long-term case-study of a rare Leucopogon species (Ericaceae)

Implemented burns are a primary source of fire in natural systems and occur outside of the wildfire season. However, the impacts of fire season shift on native plant species are rarely studied. Understanding fire season effects are particularly important for managing threatened species, which are often the focus of managed burns. To assess the impacts of fire seasonality and identify potential limiting traits, I studied the threatened Leucopogon exolasius and two common congeners, all of which persist via fire-driven population dynamics. All species were monitored over a 16 year period to assess seedling survival, growth and primary juvenile period after fire. For L. exolasius and the common L. esquamatus, comparisons of survival, growth and maturation were made after winter and summer fires, to assess the effects of season of burn. A key difference was found in primary juvenile period, which was exceptionally long for L. exolasius (>11 years for 80% of the population to flower) compared to the common congeners (3.2-7.57 years). Seasonal seed dormancy mechanisms meant that winter fires delayed emergence, leading to increases in primary juvenile period for both species. A long primary juvenile period may limit L. exolasius population persistence because plants are more likely to be killed by subsequent fire before maturation, while seasonal dormancy cues is a trait that would exacerbate the effects of this interval squeeze. In fire-prone systems, fire frequency is the key factor assumed to drive persistence, however, interactions with fire season can influence recruitment success. There are scant data on recruitment variation in response to fire seasonality, a factor that may have broad implications for rare and common species with seasonal germination requirements.

Arbutus unedo L.: From traditional medicine to potential uses in modern pharmacotherapy

ETHNOPHARMACOLOGICAL RELEVANCE

Arbutus unedo L., the strawberry tree (Ericaceae family) is of increasing interest because of its common traditional, industrial, chemical and pharmaceutical uses. The plant is a typical evergreen plant of the Mediterranean basin, as well as of other regions with hot summers and mild rainy winters. This review covers the studies relevant to Arbutus unedo L. utilization in the current pharmacological therapy.

MATERIALS AND METHODS

The available information on traditional uses, phytochemistry and biological activities of Arbutus unedo L. was collected from scientific databases through a search using the keywords 'Arbutus unedo L.' and/or 'strawberry tree' in 'Google Scholar', 'Pubmed', 'Sciencedirect', 'SpringerLink', 'Web of Science - Clarivate Analytics' and 'Wiley'. Unpublished Ph.D. and M.Sc. dissertations were also consulted for chemical composition, biological activities and traditional uses of Arbutus unedo L. and for manual search of additional references.

RESULTS

The fruits of the plant have been traditionally used as antiseptics, diuretics and laxatives in folk medicine, while the leaves have been used due to their diuretic, urinary antiseptic, antidiarrheal, astringent, depurative and antihypertensive properties. According to the scientific literature survey, different extracts obtained from Arbutus unedo L. have demonstrated a high pharmacological potential due to their in vitro and preclinical antibiotic, antifungal, antiparasitic, antiaggregant, antidiabetic, antihypertensive, anti-inflammatory, antitumoral, antioxidant, and spasmolytic properties.

CONCLUSION

This review suggests that A. unedo is a promising source of phytopharmaceutical products. The potential advantages of Arbutus unedo are related with the presence of polyphenolic compounds in its composition. However, further studies are needed to ascertain some profitable effects in humans. The beneficial effects associated with this shrub suggest that Arbutus unedo can be used for the development of new drugs to treat diseases such diabetes, hypertension, among others. Nonetheless, the safety of the Arbutus unedo compounds should also be examined.

Shift in community structure in an early-successional Mediterranean shrubland driven by long-term experimental warming and drought and natural extreme droughts

Global warming and recurring drought are expected to accelerate water limitation for plant communities in semiarid Mediterranean ecosystems and produce directional shifts in structure and composition that are not easily detected, and supporting evidence is scarce. We conducted a long-term (17 years) nocturnal-warming (+0.6°C) and drought (-40% rainfall) experiments in an early-successional Mediterranean shrubland to study the changes in community structure and composition, contrasting functional groups and dominant species, and the superimposed effects of natural extreme drought. Species richness decreased in both the warming and drought treatments. Responses to the moderate warming were associated with decreases in herb abundance, and responses to the drought were associated with decreases in both herb and shrub abundances. The drought also significantly decreased community diversity and evenness. Changes in abundance differed between herbs (decreases) and shrubs (increases or no changes). Both warming and drought, especially drought, increased the relative species richness and abundance of shrubs, favoring the establishment of shrubs. Both warming and drought produced significant shifts in plant community composition. Experimental warming shifted the community composition from Erica multiflora toward Rosmarinus officinalis, and drought consistently shifted the composition toward Globularia alypum. The responses in biodiversity (e.g., community biodiversity, changes of functional groups and compositional shifts) were also strongly correlated with atmospheric drought (SPEI) in winter-spring and/or summer, indicating sensitivity to water limitation in this early-successional Mediterranean ecosystem, especially to natural extreme droughts. Our results suggest that the shifts in species assembles and community diversity and composition are accelerated by the long-term nocturnal-warming and drought, combined with natural severe droughts, and that the magnitude of the impacts of climate change is also correlated with the successional status of ecosystem. The results thus highlight the necessity for assessing the impacts on ecosystemic functioning and services and developing effective measures for conserving biodiversity.

Treatment of pieris ingestion in goats with intravenous lipid emulsion

Seven goats and one ram presented with clinical signs including regurgitation, obtundation, anorexia, apparent pain, and bloat. The animals had escaped from their barn, and it was discovered that they had ingested leaves of Pieris japonica, Japanese pieris, a grayanotoxin-containing plant. Animals were treated with antibiotics, calcium borogluconate, B vitamins, and activated charcoal within the first 24-h postexposure, which was followed by the recovery of the ram and two goats and the death of two goats. Approximately 36 h after Japanese pieris ingestion, one of the three remaining anorectic goats was dosed with intravenous lipid emulsion (ILE). This goat recovered within a few hours. The remaining two goats were given ILE the next day and appeared to recover, but one died a week later of aspiration pneumonia.

137Cs, 239,240Pu and 241Am in boreal forest soil and their transfer into wild mushrooms and berries

Profiles of podzolic soil from boreal forests were sampled from eight sites in Finland and the distribution of (137)Cs in the soil layers was determined. In addition, (239,240)Pu and (241)Am were determined from two soil profiles taken at one sampling site. Inventories of (137)Cs in the soil profiles varied between 1.7 kBq/m(2) and 42 kBq/m(2), reflecting known variation in (137)Cs fallout from the Chernobyl accident. The highest proportions of the radionuclides were found in the organic layer at a depth of less than 5 cm, which on average contained 47% of (137)Cs, 76% of (239,240)Pu and 79% of (241)Am. In the litter, clearly higher proportions of (137)Cs were found compared to (239,240)Pu and (241)Am, probably indicating its more effective recycling from the organic layer back to the surface. Only very minor proportions of (137)Cs were recorded below 20 cm. The concentration of (137)Cs in the soil profiles could be approximated with a declining logarithmic trend. The activity concentrations of (137)Cs were determined for six wild mushroom species and three wild berry species at two sites, as well as the aggregated transfer factors and the distribution of (137)Cs between their various parts. In addition, (239,240)Pu and (241)Am were determined in one mushroom and three berry species at one site. Very high concentrations of (137)Cs, up to 20 kBq/kg (d.w.), were found in mushrooms, and their transfer factors were between 0.1 m(2)/kg and 1.0 m(2)/kg. In berries, the transfer factors were an order of magnitude lower. (137)Cs accumulated more in the caps of mushrooms and in the fruits of berries than in other parts. Transfer factors for (239,240)Pu and (241)Am were two to three orders of magnitude lower than those of (137)Cs.

Allocation of carbon to fine root compounds and their residence times in a boreal forest depend on root size class and season

Fine roots play a key role in the forest carbon balance, but their carbon dynamics remain largely unknown. We pulse labelled 50 m(2) patches of young boreal forest by exposure to (13)CO(2) in early and late summer. Labelled photosynthates were traced into carbon compounds of < 1 and 1-3 mm diameter roots (fine roots), and into bulk tissue of these and first-order roots (root tips). Root tips were the most strongly labelled size class. Carbon allocation to all size classes was higher in late than in early summer; mean residence times (MRTs) in starch increased from 4 to 11 months. In structural compounds, MRTs were 0.8 yr in tips and 1.8 yr in fine roots. The MRT of carbon in sugars was in the range of days. Functional differences within the fine root population were indicated by carbon allocation patterns and residence times. Pronounced allocation of recent carbon and higher turnover rates in tips are associated with their role in nutrient and water acquisition. In fine roots, longer MRTs but high allocation to sugars and starch reflect their role in structural support and storage. Accounting for heterogeneity in carbon residence times will improve and most probably reduce the estimates of fine root production.

Empetrum nigrum var. japonicum extract suppresses γ-ray radiation-induced cell damage via inhibition of oxidative stress

The ethylacetate fraction of Empetrum nigrum var. japonicum (ENE) was shown to reduce intracellular reactive oxygen species (ROS) generated by γ-radiation and activate antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and gluthathion peroxidase (GPx). ENE protected cells against radiation-induced cellular DNA damage, membrane lipid peroxidation, and protein modification, which are the main points of radiation-induced damage. In addition, ENE recovered cell viability by inhibiting apoptosis after cells were treated with radiation. ENE treatment also reduced γ-radiation induced Bax, and caspase 9 and 3 expression in irradiated cells. However, irradiated cells with ENE recovered Bcl-2 expression, which was reduced by radiation. This anti-apoptotic effect of ENE was due to the inhibition of mitogen-activated protein kinase kinase-4 (MKK4/SEK1)-c-Jun NH(2)-terminal kinase (JNK) cascades induced by γ-radiation. In summary, these results suggest that ENE protects cells against γ-radiation-induced oxidative stress via the reduction of ROS and attenuation of apoptosis.

Cytotoxicity screening of endemic plants from Guayana highlands

A chemical-ecology approach has been used to screen plants growing in Guyana Highlands as an indicator of production of biologically active secondary metabolites. Extracts of leaves from 19 species, most of them endemic in this area, and collected at the top of Roraima Tepui (2,723 m) were screened in vitro at different concentrations for their potential cytotoxic activity against three tumour cell lines: HT29 (colon), A549 (lung) and MDA-MB-231 (breast). MTT (tetrazolium blue) colorimetric assay was employed as cytotoxicity test. Extracts of nine species caused less than 30% growth in at least one cell line. From these species, high cytotoxic activity was detected in Casearia sylvestris var. lingua and Ledotamnus sessiliflorus extracts; medium activity was found in Cyathea sp. Two other species, Cyrilla racemiflora and Heliamphora minor showed lower but significant cytotoxicity. Further cytotoxicity-directed fractionation of these extracts would be advisable to isolate and identify the active principles of these plants.

Application of denaturing gradient gel electrophoresis for analysing the gut microflora of Lumbricus rubellus Hoffmeister under different feeding conditions

The earthworm, Lumbricus rubellus, plays an essential role in soil ecosystems as it affects organic matter decomposition and nutrient cycling. By ingesting a mixture of organic and mineral material, a variety of bacteria and fungi are carried to the intestinal tract of the earthworm. To get a better understanding of the interactions between L. rubellus and the microorganisms ingested, this study tried to reveal if the diet affects the composition of the gut microflora of L. rubellus or if its intestinal tract hosts an indigenous, species-specific microbiota. A feeding experiment with L. rubellus was set up; individuals were collected in the field, transferred to a climate chamber and fed with food sources of different quality (dwarf shrub litter, grass litter or horse dung) for six weeks. DNA was extracted from the guts of the earthworms, as well as from the food sources and the surrounding soil, and further analysed by a molecular fingerprinting method, PCR-DGGE (Polymerase Chain Reaction -- Denaturing Gradient Gel Electrophoresis). We were able to demonstrate that the gut microbiota was strongly influenced by the food source ingested and was considerably different to that of the surrounding soil. Sequencing of dominant bands of the bacterial DGGE fingerprints revealed a strong occurrence of y-Proteobacteria in all gut samples, independent of the food source. A specific microflora in the intestinal tract of L. rubellus, robust against diet changes, could not be found.

Antioxidant activity of Erica arborea

The antioxidant properties of the methanol extract of leaves and flowers of Erica arborea and the ethyl acetate, butanol and water soluble fractions were investigated. The ethyl acetate extract was found to be the richest for phenolic and flavonoid content which showed the highest antioxidant activity.

Anthelmintic and nutritional effects of heather supplementation on Cashmere goats grazing perennial ryegrass-white clover pastures1

To investigate anthelmintic and nutritional effects of heather supplementation in goats grazing perennial ryegrass-white clover pastures, 40 dry Cashmere goats were randomly assigned to 4 treatments in a 2 x 2 factorial arrangement: 2 grazing management treatments (supplementation with heather vs. nonsupplementation) and 2 anthelmintic treatments (treatment vs. nontreatment). Goats grazed continuously from May to September 2004. At the end of the grazing period, the number of dead goats due to gastrointestinal parasitism was 1 in the group supplemented with heather and dosed with anthelmintic, 4 in the group that received neither supplementation nor anthelmintic, and 0 in the other 2 groups. For goats that did not receive anthelmintic treatment, the percentage of heather in the diet was negatively correlated with fecal egg count in August (r = -0.59, P < 0.05) and September (r = -0.49, P < 0.1) and positively correlated (r = 0.54, P < 0.05) with BW changes during the grazing season. Therefore, the correlation coefficient between BW change and fecal egg count was negative (r = -0.62, P < 0.05). Rumen ammonia concentrations were always lower in supplemented goats (P < 0.05). However, VFA concentrations were greater in goats consuming heather (58.9 vs. 50.9 mmol/L), which suggests that ruminal fermentation was not adversely affected by consumption of tannins. Heather availability in the vegetation might represent a valuable opportunity and sustainable method to control gastrointestinal nematode infections in a goat production system based on grazing perennial ryegrass-white clover pastures.

Apparent metabolisable energy and digestibility of shea (Vitellaria paradoxa) fat, cocoa (Theobroma cacao) fat and soybean oil in broiler chicks

1. The objective of this experiment was to determine and compare the apparent lipid digestibility coefficient and apparent metabolisable energy (AME) value of shea nut (Vitellaria paradoxa, Gaertn.) fat in broiler chickens with that of soybean oil and cocoa fat. 2. One hundred and sixty 13-d-old male broiler chicks were used in a randomised complete block design. The fats were added at 30, 60 and 90 g/kg to a basal diet. A tenth dietary treatment was the basal feed with no added fats or oils. The birds were fed on the diets for 8 d and all droppings were collected for the final 4 d. 3. The mean coefficient of apparent lipid digestibility for shea fat (0.58) was similar to that of cocoa fat (0.54) but lower than that of soybean oil (0.95). There was evidence of a lipid x concentration interaction with the 90 g/kg shea fat diet having low lipid digestibility (0.43). 4. There was an interaction between the effects of dietary lipid concentration and test lipid on AME but, at dietary levels of 60 g/kg and below, the AME of shea fat (22.0 MJ/kg DM) and cocoa fat (26.4 MJ/kg DM) was significantly lower than that of soybean oil (39.8 MJ/kg DM).

Soil enzyme inhibition by condensed litter tannins may drive ecosystem structure and processes: the case of Kalmia angustifolia

Kalmia angustifolia is an ericaceous shrub that can rapidly spread on recently harvested boreal forest sites, causing a slow-down in soil nutrient cycling and reduced growth of spruce seedlings. It has been hypothesized that tannins released from Kalmia litter suppress soil enzyme activity, and are thus important in controlling ecosystem structure and processes. Here the effects of different concentrations of tannins extracted from both Kalmia and black spruce (Picea mariana) foliage were tested on enzyme activities of soil extracts. Then the effects of various Kalmia-black spruce litter mixtures on soil enzyme activity were investigated. Lastly, the correlation between Kalmia cover in the field and soil enzyme activity was measured. Both tannin types suppressed beta-glucosidase and acid phosphatase activities, and the magnitude of these effects was concentration-dependent. beta-glucosidase and amidase activity decreased linearly with an increasing Kalmia : spruce litter ratio added to soil. A field survey of 24 sites revealed a negative relationship between percentage Kalmia cover and beta-glucosidase activity. Collectively, results of the three experiments converge to support the claim that enzyme inhibition by litter tannins has evolved as an important mechanism controlling ecosystem processes and structure following Kalmia invasion on recently disturbed forest sites.

Intoxication par bois de gale (Agauria salicifolia)

INTRODUCTION

Several plants of the Ericaceae family produce grayanotoxins, which can poison humans. The best-known of these intoxications involves the eating of "mad honey" contaminated by rhododendron nectar grayanotoxins. The authors report a case of poisoning due to ingestion of Agauria salicifolia, an Ericaceae species endemic in the Mascarene Islands.

CASE

A 28-year-old woman mistakenly ingested a herbal tea made with leaves of this plant. Symptoms were characteristic of grayanotoxin intoxication, with vomiting, arterial hypotension and bradycardia. The patient was managed in an intensive care unit and recovered within a few hours after symptomatic treatment of the low blood pressure and the severe digestive disorders.

CONCLUSION

This case underlines that ingestion of some plants can be toxic.

Polycyclic aromatic hydrocarbons in smoke used to smoke cheese produced by the combustion of rock rose (Cistus monspeliensis) and tree heather (Erica arborea) wood

In this work, the polycyclic aromatic hydrocarbons (PAHs) and their methyl derivatives concentrations have been determined in smoke from the rock rose and tree heather wood combustion. The combustion is done in two types of smokers, kiln and drum, commonly used in the Canary Islands (Spain) to smoke cheese. The low control of the operational conditions justify the great variability of the PAHs concentration in the emissions, with values between 251.8 and 2547 microg/m3N. In general, the lowest concentrations correspond to the tree heather wood combustion in the drum, while the highest concentrations are usually reached in the rock rose wood combustion in the kiln. However, the relative contributions of each PAH to the total concentration are independently similar to the type of smoker and wood used. In the combustion conditions, the equilibrium is not reached during the PAHs distribution process between the gas and aerosol phases. Therefore, while naphthalene and their 1- and 2-methyl derivatives remain in the gas phase, phenanthrene and PAHs with higher molecular weight remain mainly in the aerosol phase. In this phase, the PAHs concentration represents 39.9% of the total PAHs produced by burning rock rose wood and 29.1% of the total PAHs when tree heather wood is used. To establish the carcinogenic potential in both phases, the percentages of some PAHs were calculated. These values are significantly higher in the aerosol phase and, at the same time, higher when rock rose wood is used.

Phosphodiesterase and thymidine phosphorylase-inhibiting salirepin derivatives from Symplocos racemosa

A re-investigation of the chemical constituents of the stem bark of Symplocos racemosa Roxb. led to the isolation of four new glycosides, symplocomoside (1), symponoside (2), symplososide (3) and symploveroside (4). Benzoylsalireposide (5) and salireposide (6) were re-isolated from this plant. The structures of the new compounds were determined by 1D and 2D-homonuclear and heteronuclear NMR spectroscopy, chemical evidence, and by comparison with the published data of the closely related compounds. The glycosides 1-4 displayed in vitro inhibitory activity against phosphodiesterase I with IC50 values of 122 +/- 0.017, 698 +/- 0.06, 722 +/- 0.03, 909 +/- 0.09 microM, respectively. The compounds 1-6 also showed in vitro inhibitory activity against thymidine phosphorylase with IC50 values of 189.96 +/- 1.02, 195.56 +/- 2.36, 207.61 +/- 1.06, 488.89 +/- 4.10, 427.20 +/- 5.36, 354.2 +/- 5.69 microM, respectively while 1 was also found to be a urease inhibitor with an IC50 value of 54.13 +/- 0.71 microM.

Effect of Symplocos racemosa Roxb. on gonadotropin release in immature female rats and ovarian histology

In the present study we are reporting in vivo effect of aqueous extracts of Symplocos racemosa Roxb. (Fam. Symplocaceae) on serum FSH and LH levels in immature female Sprague-Dawley rats under basal conditions. Symplocos racemosa is used in Indian System of Medicine (ISM) for various female disorders. Aqueous extract on oral administration significantly stimulated serum FSH level (P < 0.016) along with the rise in serum LH level (P < 0.001). Moreover, histopathological studies revealed enhanced folliculogenesis, presence of mature follicles and detached oocytes, which are result of increased FSH and LH levels. Further, an increase in the ovary weight of treated animals was found due to observed FSH surge. These results are in concordance with the traditional use of the drug for female disorders.