Cristina Giménez’s research while affiliated with University of La Laguna and other places

Background Biofungicides arise as a promising alternative to the indiscriminate use of harmful synthetic fungicides in crop management. Results The present study reports the bio‐guided fractionation of an endemic plant from the Canary Islands, Salvia canariensis against the phytopathogens, Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum. This procedure allowed identifying a series of diterpenoids with an abietane skeleton (1–5), which exhibited remarkable activity against the phytopathogenic fungi assayed. Their structures were established by means of spectroscopic and spectrometric methods, as well as comparison with reported data. Compounds 2 (carnosic acid), 4 (11‐acetoxy carnosic acid) and 5 (11,12‐diacetoxy carnosic acid) showed significant mycelium growth inhibition (%GI > 50 at 0.1 mg/mL concentration) on all the assayed fungi, and with a potency also higher than the positive control, Fosbel‐Plus, a fungicide commonly used in agriculture. A preliminary structure–activity relationship is also discussed. Conclusions These findings underline the aromatic abietane diterpenoids as promising eco‐friendly alternatives to conventional fungicides to use in integrated pest management. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Botanical biopesticides have emerged as sustainable and eco-friendly alternatives to synthetic pesticides, whose indiscriminate use leads to several drawbacks to human and environmental health. To the best of our knowledge, there have been no reports on M. pubescens’ bioactivity on phytopathogens affecting crops as a potential fungicide or antifeedant. This has encouraged us to investigate the potential of the roots of this plant as a source of biopesticides. The present study reports on the evaluation of the roots extract from Magonia pubescens A. St.-Hill., a species from the Cerrado (Brazilian savannah), on the phytopathogenic fungi Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata. In addition, its insect antifeedant effect was assayed against Chrysodeixis chalcites. Thus, an in vitro test-assay was used to determine the fungicide potential (percentage growth inhibition, % GI) of the ethanolic extract of this plant species, whereas a leaf-disk bioassay on the 5th instar larvae of C. chalcites was performed to evaluate its insecticidal potential. The ethanolic extract was further fractionated by liquid–liquid partition using solvents of increasing polarity. The hexane/dichloromethane fraction exhibited a moderated potency and was similar to the ethanolic extract on the three assayed fungi (around % GI 30 at 1 mg/mL), whereas the n-butanol fraction showed a slight improvement of the fungicide effect against B. cinerea (% GI 39.18 at 1 mg/mL). Moreover, the ethanolic extract exhibited a strong antifeedant activity, with a refusal rate (FR) higher than 90% in both choice and non-choice assays against C. chalcites, while the ethyl acetate and n-butanol fractions behaved as appetite suppressors. These results highlight M. pubescens as a promising source of biopesticides and deserve further investigations to optimize extraction procedures.

Botanical biopesticides have emerged as sustainable and eco-friendly alternatives to synthetic pesticides, whose indiscriminate use leads to several drawbacks to human and environment health. The present study reports on the evaluation of the roots extract from Magonia pubescens, species from the Cerrado (Brazilian savannah), on the phytopathogenic fungi, Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum. In addition, its insect antifeedant effect was assayed against Chrysodeixis chalcites. Thus, an in vitro test-assay was used to determine the fungicide potential (percentage growth inhibition, % GI) of the ethanolic extract of this plant species, whereas a leaf-disk bioassay on the 5th instar larvae of C. chalcites was performed to evaluate the insecticide potential. The ethanolic extract was further fractionated by liquid-liquid extraction, using organic solvents of increasing polarity. The hexane/dichloromethane fraction exhibited a moderated potency, and similar to the ethanolic extract on the three assayed fungi (around % GI 30 at 1 mg/mL), whereas the n-butanol fraction showed a slight improvement of the fungicide effect against B. cinerea (% GI 39.18 at 1 mg/mL). Moreover, the etanolic extract exhibited a strong antifeedant activity, with a refusal rate (FR) higher than 90% in both choice and non-choice assays against C. chalcites, while the ethyl acetate and n-butanol fractions behaved as appetite suppressors. These results highlight M. pubescens as a promising source of biopesticides and deserve further investigations to optimize extraction procedures.

Phytopathogens are responsible for great losses in agriculture. In particular, Fusarium, Alternaria and Botrytis are fungal diseases that affect crops worldwide. In the search for eco-friendly solutions to pest control, plants and their chemo-biodiversity are promising sources of biopesticides for integrated pest management. The aim of the present study is to report the evaluation of sixteen plant species from the Canary Islands Archipelago against the phytopathogenic fungi Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata. The plants were selected on the basis of their traditional uses in medicine and/or pest control, as well as on scientific studies reporting their uses in crop protection. Their growth inhibition (% I), in an in vitro test-assay on mycelium, was used to identify six ethanolic plant extracts displaying activity (% I > 30% at 1 mg/mL) against at least one of the assayed fungi. The most effective plant extracts were further fractionated by liquid–liquid partition, using solvents of increasing polarity. This procedure led to an improvement of the bioactivity against the phytopathogens, even affecting the hexane fraction from S. canariensis and achieving an 83.93% of growth inhibition at 0.5 mg/mL on B. cinerea. These findings identified five plant-derived extracts as potential candidates for the future development of new biofungicides, which could be applied in integrated pest management.

Nicotiana glauca it is naturally distributed throughout South America. It was introduced in North America, Europe, Africa, Asia and Oceania and arrived to the Canary Islands as an ornamental plant, where has been invading altered soils. Endophytic fungi are known to produce active compounds that provide protection to their host against diseases and attack of herbivores, these microorganisms being an interesting source of novel molecules. So far, the endophytic fungal communities of Nicotiana have not been studied in the Canary Islands. The goal of this study is to evaluate the diversity of the fungal endophytes community associated with Nicotiana glauca. A total of 36 fungal species were isolated from roots, stems and leaves of plants collected in three locations from Tenerife Island - San Miguel de Abona, Fasnia and Puerto de la Cruz. The highest species richness values were found in leaves and stems (Margalef index = 3.33 and 3.36, respectively) versus roots (Margalef index = 2.52). Simpson's index complements the results of the Margalef index, indicating a fungal community with a high dominance value in roots (D = 0.65) due to the presence of multiple Fusarium species. Fungal community in Fasnia had the highest value of species richness (Margalef index = 3.69 versus 2.17 and 2.27 for San Miguel de Abona and Puerto de la Cruz, respectively). Results indicate fungal specificity to organ and location with 13 genera isolated from a single location and organ, among which rare species like Collariella and Gelasinospora. In this study was detected and isolated for the first time in Canary Islands the fungal species Collariella hilkhuijsenii which is of importance for the ecology of this genus scarcely known. Special attention should be offered to the presence of Fusarium, which possibly relates to the alkaloid production ability of both, the plant and the fungal strains.

Nicotiana glauca it is naturally distributed throughout South America. It was introduced in North America, Europe, Africa, Asia and Oceania and arrived to the Canary Islands as an ornamental plant, where has been invading altered soils. Endophytic fungi are known to produce active compounds that provide protection to their host against diseases and attack of herbivores, these microorganisms being an interesting source of novel molecules. So far, the endophytic fungal communities of Nicotiana have not been studied in the Canary Islands. The goal of this study is to evaluate the diversity of the fungal endophytes community associated with Nicotiana glauca. A total of 36 fungal species were isolated from roots, stems and leaves of plants collected in three locations from Tenerife Island - San Miguel de Abona, Fasnia and Puerto de la Cruz. The highest species richness values were found in leaves and stems (Margalef index = 3.33 and 3.36, respectively) versus roots (Margalef index = 2.52). Simpson's index complements the results of the Margalef index, indicating a fungal community with a high dominance value in roots (D = 0.65) due to the presence of multiple Fusarium species. Fungal community in Fasnia had the highest value of species richness (Margalef index = 3.69 versus 2.17 and 2.27 for San Miguel de Abona and Puerto de la Cruz, respectively). Results indicate fungal specificity to organ and location with 13 genera isolated from a single location and organ, among which rare species like Collariella and Gelasinospora. In this study was detected and isolated for the first time in Canary Islands the fungal species Collariella hilkhuijsenii which is of importance for the ecology of this genus scarcely known. Special attention should be offered to the presence of Fusarium, which possibly relates to the alkaloid production ability of both, the plant and the fungal strains.