The native distribution of a common legume shrub is limited by the range of its nitrogen-fixing mutualist.

Plant-microbe mutualisms, such as the legume-rhizobium symbiosis, are influenced by the geographical distributions of both partners. However, limitations on the native range of legumes, resulting from the absence of a compatible mutualist, have rarely been explored. We used a combination of a large-scale field survey and controlled experiments to determine the realized niche of Calicotome villosa, an abundant and widespread legume shrub. Soil type was a major factor affecting the distribution and abundance of C. villosa. In addition, we found a large region within its range in which neither C. villosa nor Bradyrhizobium, the bacterial genus that associates with it, were present. Seedlings grown in soil from this region failed to nodulate and were deficient in nitrogen. Inoculation of this soil with Bradyrhizobium isolated from root nodules of C. villosa resulted in the formation of nodules and higher growth rate, leaf N and shoot biomass compared with un-inoculated plants. We present evidence for the exclusion of a legume from parts of its native range by the absence of a compatible mutualist. This result highlights the importance of the co-distribution of both the host plant and its mutualist when attempting to understand present and future geographical distributions of legumes.

New Compounds from the Roots of Corsican Calicotome Villosa (Poir.) Link.: Two Pterocarpans and a Dihydrobenzofuran.

Three new compounds, a dihydrobenzofuran (coumaran) derivative (compound 1) and two pterocarpans (compounds 2 and 3) were isolated from a root extract of Calicotome villosa growing wild in Corsica. Their structures were elucidated using 1D and 2D NMR spectroscopy and MS/MS as 2-(1-methylethenyl)-5-hydroxy-6-carbomethoxy-2,3-dihydro-benzofuran, 4,9-dihydroxy-3-methoxy-2-dimethylallylpterocarpan, and 4,9-dihydroxy-3',3'-dimethyl-2,3-pyranopterocarpan.

Symbiotic dinitrogen fixation is seasonal and strongly regulated in water-limited environments.

Plants, especially perennials, growing in drylands and seasonally dry ecosystems are uniquely adapted to dry conditions. Legume shrubs and trees, capable of symbiotic dinitrogen (N2 ) fixation, often dominate in drylands. However, the strategies that allow symbiotic fixation in these ecosystems, and their influence on the nitrogen cycle, are largely unresolved. We evaluated the climatic, biogeochemical and ontogenetic factors influencing nitrogen fixation in an abundant Mediterranean legume shrub, Calicotome villosa. We measured nodulation, fixation rate, nitrogen allocation and soil biogeochemistry in three field sites over a full year. A controlled experiment evaluated differences in plant regulation of fixation as a function of soil nutrient availability and seedling and adult developmental stages. We found a strong seasonal pattern, shifting between high fixation rates during the rainy season at flowering and seed-set times to almost none in the rainless season. Under controlled conditions, plants downregulated fixation in response to soil nitrogen availability, but this response was stronger in seedlings than in adult shrubs. Finally, we did not find elevated soil nitrogen under N2 -fixing shrubs. We conclude that seasonal nitrogen fixation, regulation of fixation, and nitrogen conservation are key adaptations influencing the dominance of dryland legumes in the community, with broader consequences on the ecosystem nitrogen cycle.

Isolation of Bioactive Compounds from Calicotome villosa Stems.

A phenylethanoid, two steroids, a flavone glucoside and a chalcone have been isolated for the first time from the stems of Calicotome villosa together with a previously isolated flavone glucoside. Their structures were determined by spectroscopic analyses (NMR, HRMS) as basalethanoïd B (1), ß-sitosterol and stigmasterol (2), chrysine-7-O-ß-d-glucopyranoside (3), chrysine 7-((6''-O-acetyl)-O-ß-d-glucopyranoside) (4) and calythropsin (5). The crude extracts and the isolated compounds (except 4), were evaluated for their antioxidant, antimicrobial (against two Gram-positive bacterial strains: Staphylococcus aureus, Bacillus cereus, four Gram-negative bacterial strains: Staphylococcus epidermidis, Klebsiella pneumonia, Acinetobacter baumanii, and three yeasts: Candida albicans, Candida tropicalis, and Candida glabrata), hemolytic, antidiabetic, anti-inflammatory and cytotoxic activity. The crude extracts showed good ability to scavenge the free radical DPPH. Methanol stem extract followed by the dichloromethane stem extract showed moderate antimicrobial potency; furthermore, at 1 mg/mL the methanol extract showed an inhibition of C. albicans growth comparable to nystatin. Dichloromethane, methanol, and aqueous extracts inhibited 98%, 90%, and 80% of HeLa cell proliferation at 2 mg/mL respectively. Weak hypoglycemic and hemolytic effects were exhibited by the crude extracts. Among all the tested compounds, compound 3 showed remarkable hypoglycemic potential (93% at 0.1 mg/mL) followed by compound 5 (90% at 0.3 mg/mL). Compound 5 was the most effective in the DPPH. scavenging assay (100% at 0.1 mg/mL) and cytotoxic assay on HeLa cells (99% and 90% after 24 and 48 h of treatment at 0.1 mg/mL, respectively). No anti-inflammatory effects were displayed by any of the crude extracts or the isolated compounds at any of the tested concentrations.

Preparations based on minerals extracts of Calicotome villosa roots and bovine butyrate matter: Evaluation in vitro of their antibacterial and antifungal activities.

OBJECTIVE: The use of preparations based on minerals extracts of Calicotome villosa and butter is born from the misuse of drugs without specific microbiological analyzes. Seventeen different preparations were performed. The antibacterial and antifungal activities were determined on five bacteria and two fungi strains respectively. MATERIAL AND METHODS: C.villosa ashes are obtained by incineration of roots plant at 498°C for 4hours. They are analyzed to determine the shape of the particles and the mineral constituents by scanning electronic microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) techniques respectively. The effectiveness of preparations or tablets is measured in solid medium. It allows to calculating the diameter of the inhibition zone for the antibacterial activity as well as the diameter of mycelia growth and the critical values (MIC, MFC, IC50 and IC90) for the antifungal activity. Finally, the results are compared to the activity of a commercial positive control aiming to give value of the observed activity. RESULTS: SEM observations reveal the presence of nanoparticles agglomerated with size of about 50nm. The EDX analyzes indicate the presence of Fe, Na, Al, Mg, Si, K, Ca, O2 and C. Among all the results, the preparation (Bs+A) or (Bsd+A) can completely inhibit the growth of two fungal pathogens. The activity of the preparation is faced with the activity of the synthetic fungicide nystatin. CONCLUSION: The efficacy of the preparation (Bs+A) or (Bsd+A) is larger than that of nystatin against Aspergillus sp. and Fusarium sp. The preparation could serve as natural antifungal for the pharmaceutical industry.

Preparations based on minerals extracts of Calicotome villosa roots and bovine butyrate matter: Evaluation in vitro of their antifungal activity.

OBJECTIVE: The use of preparations based on minerals extracts of Calicotome villosa and butter is born from the misuse of drugs without specific microbiological analyzes. Seventeen different preparations were performed. The antibacterial and antifungal activities were determined on five bacteria and two fungi strains respectively. MATERIAL AND METHODS: C. villosa ashes are obtained by incineration of roots plant at 498°C for 4hours. They are analyzed to determine the shape of the particles and the mineral constituents by scanning electronic microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques respectively. The effectiveness of preparations or tablets is measured in solid medium. It allows to measure the diameter of the inhibition zone for the antibacterial activity as well as the diameter of mycelia growth and the critical values (MIC, MFC, IC50 and IC90) for the antifungal activity. Finally, the results are compared to the activity of a commercial positive control aiming to give value of the observed activity. RESULTS: SEM observations reveal the presence of nanoparticles agglomerated with size of about 50nm. The EDX analyzes indicate the presence of Fe, Na, Al, Mg, Si, K, Ca, O2 and C. Among all the results, the preparation (Bs+A) or (Bsd+A) can completely inhibit the growth of two fungal pathogens. The activity of the preparation is faced with the activity of the synthetic fungicide nystatin. CONCLUSION: The efficacy of the preparation (Bs+A) or (Bsd+A) is higher than that of nystatin against Aspergillus sp. and Fusarium sp. The preparation could serve as natural antifungal for the pharmaceutical industry.