Can arbuscular mycorrhizal fungi from non-invaded montane ecosystems facilitate the growth of alien trees?

It is generally assumed that recruitment and expansion of alien species along elevation gradients are constrained by climate. But, if plants are not fully constrained by climate, their expansion could be facilitated or hindered by other factors such as biotic interactions. Here, we assessed the composition of arbuscular mycorrhizal fungi (AMF) in soils along an elevation gradient (i.e. 900 m, 1600 m, 2200 m and 2700 m a.s.l.) through a fungal DNA meta-barcoding approach. In addition, we studied in the greenhouse the effects of AMF on growth and phosphorous (P) nutrition of seedlings of the alien trees Gleditsia triacanthos, Ligustrum lucidum and Pyracantha angustifolia cultivated in soils from those elevations, spanning the elevation at which they already form monospecific stands (below 1450 m a.s.l.) and higher elevations, above their current range of distribution in montane ecosystems of Central Argentina. For comparison, we also included in the experiment the dominant native tree Lithraea molleoides that historically occurs below 1300 m a.s.l. Arbuscular mycorrhizal fungal community composition showed strong community turnover with increasing elevation. The effects of these AMF communities on plant growth and nutrition differed among native and alien trees. While P nutrition in alien species' seedlings was generally enhanced by AMF along the whole gradient, the native species benefited only from AMF that occur in soils from the elevation corresponding to its current altitudinal range of distribution. These results suggest that AMF might foster upper range expansion of these invasive trees over non-invaded higher elevations.

Optimization of Fermentation Condition for Echinacoside Yield Improvement with Penicillium sp. H1, an Endophytic Fungus Isolated from Ligustrum lucidum Ait Using Response Surface Methodology.

(1) Background: Application of echinacoside has become increasingly important for its significant biological activities. However, there are many disadvantages in existing synthesis methods such as contaminating the environment, harsh reaction conditions and so on. Therefore, it is urgent to invent a novel alternative method that can increase the yield of echinacoside. (2) Methods: In this study, we isolated and purified an endophyte from the leaves of Ligustrum lucidum Ait. Then, we improved the yield of echinacoside by optimizing the fermentation condition with an endophytic fungus. Penicillium sp. H1 was isolated from Ligustrum lucidum Ait. In addition, response surface methodology was used to optimize the fermentation condition. (3) Results: The results indicate that the maximal yield of echinacoside (37.16 mg/L) was obtained when inoculation rate, temperature and days were 13.98%, 27.85 °C and 26.06 days, respectively. The yield of echinacoside was 150.47 times higher under the optimal conditions than under the control conditions. The results indicate that the yield of echinacoside could be improved with endophytic fermentation by optimizing the fermentation condition. We provide an alternative method for echinacoside production by endophytic fermentation in this paper. It may have a profound effect on the application of echinacoside.

Fungal decomposers of leaf litter from an invaded and native mountain forest of NW Argentina.

The impact of plant species invasions on the abundance, composition and activity of fungal decomposers of leaf litter is poorly understood. In this study, we isolated and compared the relative abundance of ligninocellulolytic fungi of leaf litter mixtures from a native forest and a forest invaded by Ligustrum lucidum in a lower mountain forest of Tucuman, Argentina. In addition, we evaluated the relationship between the relative abundance of ligninocellulolytic fungi and properties of the soil of both forest types. Finally, we identified lignin degrading fungi and characterized their polyphenol oxidase activities. The relative abundance of ligninocellulolytic fungi was higher in leaf litter mixtures from the native forest. The abundance of cellulolytic fungi was negatively related with soil pH while the abundance of ligninolytic fungi was positively related with soil humidity. We identified fifteen genera of ligninolytic fungi; four strains were isolated from both forest types, six strains only from the invaded forest and five strains were isolated only from the native forest. The results found in this study suggest that L. Lucidum invasion could alter the abundance and composition of fungal decomposers. Long-term studies that include an analysis of the nutritional quality of litter are needed, for a more complete overview of the influence of L. Lucidum invasion on fungal decomposers and on leaf litter decomposition.

Phomosines H-J, novel highly substituted biaryl ethers, isolated from the endophytic fungus Phomopsis sp. from Ligustrum vulgare.

From the endophytic fungus Phomosis sp., four known phomosines A-D (1-4) and three new phomosines H-J (5-7) have been isolated. The structures of the new compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as mass spectrometry). The structures of phomosine H (5) and J (7) were also confirmed by semisynthesis from phomosine A (1). The remaining four known compounds [phomosines A-D (1-4)] were identified by comparing their spectroscopic data with those reported in the literature. The four known metabolites were biologically active. Of the novel metabolites, only 6 was antifungal and antibacterial.