Genomic Sequences of Five Helicoverpa armigera Nucleopolyhedrovirus Genotypes from Spain That Differ in Their Insecticidal Properties.

Helicoverpa armigera nucleopolyhedrovirus (HearNPV) has proved effective as the basis for various biological insecticides. Complete genome sequences of five Spanish HearNPV genotypes differed principally in the homologous regions (hrs) and the baculovirus repeat open reading frame (bro) genes, suggesting that they may be involved in the phenotypic differences observed among genotypes.The Departamento de Innovación, Empresa y Empleo, Gobierno de Navarra (project IIQ14065.RI1), funded the study. M.A. received a fellowship from CSIC.Peer Reviewe

Nuevos genotipos del nucleopoliedrovirus simple de Chrysodeixis chalcites (ChchSNPV), procedimiento para su producción y uso como agente de control biológico

Se describen tres nuevos genotipos del nucleopoliedrovirus de Chrysodeixis chalcites, ChchSNPV, purificados de un mismo aislado de las Islas Canarias. Cada uno de los genotipos tiene una actividad insecticida específica frente a larvas de ChchSNPV comparable a la de los insecticidas biológicos habituales. Además, la mezcla de los tres genotipos, particularmente en proporción 36:26:14, ya sea en forma de poliedros de un único genotipo o con viriones co-ocluidos de genotipos mezclados, es capaz de controlar las plagas de ChchSNPV en platanera de forma más eficiente que los insecticidas habituales, químicos o biológicos, siendo de los nucleopoliedrovirus más activos de los desarrollos como bioinsecticidas. Su uso como insecticida representa una tecnología segura para los vertebrados por ser específicos de invertebrados. Además, pueden producirse con facilidad y buen rendimiento por inoculación oral de larvas de C. chalcites con poliedros de ChchSNPV.Peer reviewedUniversidad Pública de Navarra, Consejo Superior de Investigaciones Científicas, Instituto canario de Investigaciones Agrarias, Instituto de EcologíaA1 Solicitud de patente con informe sobre el estado de la técnic

Perturbation-Theory and Machine Learning (PTML). Model for High-Throughput Screening of Parham Reactions: Experimental and Theoretical Studies

Machine Learning (ML) algorithms are gaining importance in the processing of chemical information and modelling of chemical reactivity problems. In this work, we have developed a PTML model combining Perturbation-Theory (PT) and ML algorithms for predicting the yield of a given reaction. For this purpose, we have selected Parham cyclization, which is a general and powerful tool for the synthesis of heterocyclic and carbocyclic compounds. This reaction has both structural (substitution pattern on the substrate, internal electrophile, ring size, etc.) and operational variables (organolithium reagent, solvent, temperature, time, etc.), so predicting the effect of changes on substrate design (internal elelctrophile, halide, etc.) or reaction conditions on the yield is an important task that could help to optimize the reaction design. The PTML model developed uses PT operators to account for perturbations in experimental conditions and/or structural variables of all the molecules involved in a query reaction compared to a reaction of reference. Thus, a dataset of >100 reactions has been collected for different substrates and internal electrophiles, under different reaction conditions, with a wide range of yields (0 – 98%). The best PTML model found using General Linear Regression (GLR) has R = 0.88 in training and R = 0.83 in external validation series for 10000 pairs of query and reference reactions. The PTML model has a final R = 0.95 for all reactions using multiple reactions of reference. We also report a comparative study of linear vs. non-linear PTML models based on Artificial Neural Networks (ANN) algorithms. PTML-ANN models (LNN, MLP, RBF) with R ≈ 0.1 - 0.8 do not outperform the first PMTL model. This result confirms the validity of the linearity of the model. Next, we carried out an experimental and theoretical study of non-reported Parham reactions to illustrate the practical use of the PTML model. A 500000-point simulation and a Hammett analysis of the reactivity space of Parham reactions are also reportedMinisterio de Economía y Competitividad (CTQ2016-74881-P) / Ministerio de Economía y Competitividad (CTQ2013-41229-P) / Gobierno Vasco (IT1045-16

First study on the root endophytic fungus Trichoderma hamatum as an entomopathogen: development of a fungal bioinsecticide against cotton leafworm (Spodoptera littoralis)

Producción CientíficaCotton leaf worm (Spodoptera littoralis) is a pest that produces important losses in horticultural and ornamental crops in greenhouse, being classified as quarantine pest A2 by EPPO. One of the strategies proposed to control agricultural pests in a health and environmentally friendly way is biological control with entomopathogenic fungi. The genus of filamentous fungi Trichoderma includes different species with direct (infection, antibiosis, anti-feeding, etc.) and indirect (systemic activation of plant defenses) insecticidal capacity, however, the species T. hamatum has never been described previously as entomopathogenic. In this work, the entomopathogenic capacity of T. hamatum on S. littoralis L3 larvae was analyzed by applying spores and fungal filtrates (topically and orally). Infection by spores was compared with the commercial entomopathogenic fungus Beauveria bassiana, obtaining similar results with respect to the production of larval mortality. Oral application of spores reported high mortality and fungal colonization of larvae, however, T. hamatum did not show chitinase activity when grown in the presence of S. littoralis tissues. Therefore, infection of S. littoralis larvae by T. hamatum is through natural openings such as mouth, anus or spiracles. With respect to the application of filtrates, only those obtained from the liquid culture of T. hamatum in contact with S. littoralis tissues reported a significant reduction in larval growth. Metabolomic analysis of the filtrates determined that the filtrate with insecticidal capacity presented the siderophore rhizoferrin in large quantities, which could be responsible for this activity. However, the production of this siderophore had never been previously described in Trichoderma and its insecticidal capacity was unknown. In conclusion, T. hamatum presents entomopathogenic capacity against S. littoralis larvae through the application of spores and filtrates, and both ways could be the basis for the development of efficient bioinsecticides against the pest.Gobierno de Navarra (PC093-094 FORINSEC)Xunta de Galicia (IN607A 2021/03