The cypsela (achene) of Echinacea purpurea as a diffusion unit of a community of microorganisms

Echinacea purpurea is a plant cultivated worldwide for its pharmaceutical properties, mainly related to the stimulation of the immune system in the treatment of respiratory infections. The cypselas (fruits) of E. purpurea were examined in order to investigate the presence, localization and potential function(s) of endophytic microorganisms. Electron and confocal microscopy observations showed that three different components of microorganisms were associated to cypselas of E. purpurea: (i) one endocellular bacterial component in the cotyledons, enclosed within the host membrane; (ii) another more generic bacterial component adhering to the external side of the perianth; and (iii) a fungal component inside the porous layer of the perianth, the woody and porous modified residual of the flower, in the form of numerous hyphae able to cross the wall between adjacent cells. Isolated bacteria were affiliated to the genera Paenibacillus, Pantoea, and Sanguibacter. Plate tests showed a general resistance to six different antibiotics and also to an antimicrobial-producing Rheinheimera sp. test strain. Finally, microbiome-deprived E. purpurea seeds showed a reduced ability to germinate, suggesting an active role of the microbiome in the plant vitality. Our results suggest that the endophytic bacterial community of E. purpurea, previously found in roots and stem/leaves, might be already carried at the seed stage, hosted by the cotyledons. A further microbial fungal component is transported together with the seed in the perianth of the cypsela, whose remarkable structure may be considered as an adaptation for fungal transportation, and could influence the capability of the seed to germinate in the soil

Preliminary results of EOLIFE99, a project concerning the conservation of four endangered plant species of Aeolian Archipelago (South Tyrrhenian Sea, Italy)

The LIFE-Nature project “EOLIFE99” (LIFE99 NAT/IT/006217) aims to encourage the preservation of four endangered plant species (“of priority interest” following E.U. Directive 92/43) which grow in the Aeolian Archipelago: these are Bassia saxicola (Guss.) A. J. Scott (Chenopodiaceae), Silene hicesiae Brullo & Signorello (Caryophyllaceae), Cytisus aeolicus Guss. (Leguminosae), Ophrys lunulata Parl. (Orchidaceae). The preliminary results concerning the botanical and entomological field surveys, and the in vitro propagation of Silene hicesiae, the isolation and the characterisation of Cytisus aeolicus rhizobia are here illustrated