IMAB - Institute for Multidisciplinary Research in Applied Biology

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Open Access
101 Dothideomycetes genomes: a test case for predicting lifestyles and emergence of pathogens
(Westerdijk Fungal Biodiversity Institute, 2020) Haridas, Sajeet; Castanera Andrés, Raúl; Culley, D. E.; Daum, C.; Ramírez Nasto, Lucía; Alfaro Sánchez, Manuel; Institute for Multidisciplinary Research in Applied Biology - IMAB
Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species.
Open Access
8ª Edición de la Escuela de verano de Ecología de Navarra: ecólogas/os por un día
(Asociación Española de Ecología Terrestre, AEET, 2022) Imbert Rodríguez, Bosco; Blanco Vaca, Juan Antonio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Durante los pasados 23 y 24 de junio tuvo lugar la 8ª edición de la Escuela de Verano de Ecología de Navarra de la Universidad Pública de Navarra (UPNA) con el título ‘Ecólogas/os por un día’. En la jornada se impartieron cuatro ponencias por parte de los miembros del grupo de investigación de Ecología y Medio Ambiente de la Universidad Pública de Navarra, pero la mayor parte del tiempo se dedicó al trabajo de campo en el parque. En dicho trabajo de campo los asistentes pudieron trabajar tres temas diferentes: el estudio de las comunidades vegetales en pastos, el estudio de la estructura de una comunidad arbórea y la observación y estimación de censos de aves. Los trabajos incluyeron la demostración y familiarización de los estudiantes con las distintas técnicas y aparatos para medir variables ambientales como luz ambiental, temperatura del suelo, humedad del suelo, diámetro y altura de árboles, así como las técnicas para realizar inventarios florísticos o de fauna.
Open Access
Abundance and trait-matching both shape interaction frequencies between plants and birds in seed-dispersal networks
(Elsevier, 2023) Peña, Rocío; Schleuning, Matthias; Dalerum, Fredrik; Donoso, Isabel; Rodríguez Pérez, Javier; García, Daniel; Institute for Multidisciplinary Research in Applied Biology - IMAB
Abundance and trait-driven processes have both been identified as potential mechanisms in determining the occurrence of species interactions. However, little is known about how these two mechanisms interact to determine the relative frequencies of interactions between species, and thereby species-specific contributions to ecological functions. Here, we evaluate the effect of both species¿ abundance and trait-matching on the occurrence of plant-bird seed dispersal interactions in the Cantabrian Range (northern Spain). For two years at fourteen plots, we independently sampled the abundance and diversity of fleshy-fruited plants and frugivores, as well as the consumption of fruits by birds. We quantified trait-matching by applying a food-web approach based on the log-ratios of species traits relevant to seed dispersal and traits related to fruit-handling and foraging-stratum. We fitted multi-level models incorporating phylogenetic relatedness to identify phylogenetically independent effects of species abundance and trait-matching on interaction frequencies. Fitted models showed that species abundances of both plants and birds always had strong positive effects on interaction frequencies. Trait-matching effects associated with fruit-handling were weak, but consistent across years, whereas those derived from foraging stratum varied across years, according to strong interannual changes in species abundance. Our findings reveal that both species abundance and functional traits are required for a mechanistic understanding of species interactions, as well as for predicting species roles in ecosystems under global change.
Open Access
Activation of sweet pepper defense responses by novel and known biocontrol agents of the genus Bacillus against Botrytis cinerea and Verticillium dahliae
(Springer, 2022) Poveda Arias, Jorge; Calvo, Javier; Barquero, Marcia; González Andrés, Fernando; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The Fresno-Benavente Pepper (F-BP) Protected Geographical Indication (PGI) is a horticultural crop characterized by its great agronomic, economic and cultural importance in the region of Castilla y León (Spain). Field production is threatened by verticillium wilt caused by Verticillium dahliae and postharvest losses due to grey mould caused by Botrytis cinerea. Eight Bacillus spp. strains endophytically isolated from F-BP roots were used in the study. By conducting an in vitro antagonism study, we found that all Bacillus strains were effective against B. cinerea and five of them showed high antagonism against V. dahliae, with B. siamensis and B. proteolyticus strains being the most effective against both pathogens. Eight Bacillus strains were used for an infection test in F-BP fruits and plants to test their activity against both fungal pathogens. We report that Bacillus thuringiensis, B. siamensis and B. pumilus (SCFC 1–2) could control B. cinerea in pepper fruits through direct action and local activation of plant defences. In the case of V. dahliae root infection, plant roots inoculated with B. siamensis and B. proteolyticus were able to significantly decrease the occurrence of disease through direct action and local activation of jasmonic acid as a defence response. Therefore, we propose that B. siamensis could be used to control B. cinerea and V. dahliae in F-BP fruits and plants, respectively, through direct antagonism as well as the induction of local plant defence responses.
Open Access
Activity of ammonia-oxidizing bacteria in enriched cultures exposed to 3,4-dimethyl-1H-pyrazole dihydrogen phosphate nitrification inhibitor
(Elsevier, 2023) Rodrigues dos Santos, Janaina Maria; Cruz, Cristina; Tenreiro, Rogerio; Gouveia, Catarina; Lasa Larrea, Berta; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The use of nitrification inhibitors is an interesting tool to achieve a higher N efficiency in plants while decreasing the environmental impact of N fertilization. However, an integrated evaluation of the efficiency of nitrification inhibitors over time, understood as the period in which the nitrifying activity is inhibited or slows down, is necessary to assess whether their use is ecofriendly and sustainable. To test the direct efficiency of 3,4-dimethyl-1H-pyrazole dihydrogen phosphate (DMPP) on nitrification, a study has been carried out in two cultures enriched with ammonia-oxidizing bacteria (AOB) obtained from a soil with continuous N fertilization (80 kg N ha−1 year−1 as NH4NO3) and from soil without N fertilization. In addition, Cu has been evaluated as a cofactor of ammonia monoxygenase, a key enzyme in the nitrifying activity of AOBs. On the other hand, the stability of DMP has been studied both in the cultivation system enriched in AOBs and in soil to assess the efficiency of the inhibitor due to its persistence over time. Our work reveals that nitrification rates observed in cultures enriched in AOBs from genus Nitrosospira isolated from soils with continuous N fertilization were not higher than those of cultures without N fertilization. In AOB cultures, DMPP was a very efficient inhibitor of nitrification (> 50 % inhibition of integrated AMO activity), mainly due to the stability of DMP (3,4-dimethyl-1 H-pyrazole) in the cultures. However, DMP stability was significantly lower under soil conditions (> 90 % of DMP was degraded in the first 30 days of incubation). Other metals are suggested as cofactors of the enzyme ammonia monooxygenase alternatively to Cu.
Open Access
Additive effects of heatwave and water stresses on soybean seed yield is caused by impaired carbon assimilation at pod formation but not at flowering
(Elsevier, 2022) Soba Hidalgo, David; Arrese-Igor Sánchez, César; Aranjuelo Michelena, Iker; Institute for Multidisciplinary Research in Applied Biology - IMAB; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Heatwave (HW) combined with water stress (WS) are critical environmental factors negatively affecting crop development. This study aimed to quantify the individual and combined effects of HW and WS during early reproductive stages on leaf and nodule functioning and their relation with final soybean seed yield (SY). For this purpose, during flowering (R2) and pod formation (R4) soybean (Glycine max L. Merr.) plants were exposed to different temperature (ambient[25ºC] versus HW[40ºC]) and water availability (full capacity versus WS[20% field capacity]). HW, WS and their combined impact on yield depended on the phenological stage at which stress was applied being more affected at R4. For gas exchange, WS severely impaired photosynthetic machinery, especially when combined with HS. Impaired photoassimilate supply at flowering caused flower abortion and a significant reduction in final SY due to interacting stresses and WS. On the other hand, at pod formation (R4), decreased leaf performance caused additive effect on SY by decreasing pod setting and seed size with combined stresses. At the nodule level, WS (alone or in combination with HW) caused nodule impairment, which was reflected by lower leaf N. Such response was linked with a poor malate supply to bacteroids and feed-back inhibition caused by nitrogenous compounds accumulation. In summary, our study noted that soybean sensitivity to interacting heat and water stresses was highly conditioned by the phenological stage at which it occurs with, R4 stage being the critical moment. To our knowledge this is the first soybean work integrating combined stresses at early reproductive stages.
Open Access
Agronomic evaluation of eight 41 B × 110 richter grapevine genotypes as rootstock candidates for mediterranean viticulture
(KeAi Communications, 2023) Marín Ederra, Diana; Miranda Jiménez, Carlos; Abad Zamora, Francisco Javier; Urrestarazu Vidart, Jorge; Mayor Azcona, Blanca; Villa Llop, Ana; Santesteban García, Gonzaga; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Choosing the most appropriate rootstock(s) is a key decision for the profitability of vineyards; therefore, there must be a sufficient range of rootstocks in the market adapted to different environmental conditions and production objectives. However, rootstock-breeding programs have been scarce in recent decades, and most of the rootstocks used today were bred a century ago, when the needs of the sector were very different from today. In this work, we aimed to evaluate new rootstock candidates before their introduction in the market. An agronomic evaluation was conducted on eight novel rootstock genotypes obtained from the first generation of the cross-pollination of 41 B Millardet et de Grasset (41 B) and 110 Richter (110 R) grafted with ‘Syrah’ and ‘Tempranillo’ and planted in a typical vineyard of the Ebro Valley in Spain. During the four consecutive growing seasons (2016e2019), growth, yield and berry composition parameters at harvest were collected. A linear mixedeffects model was constructed, considering year and block as random effects. Multiple factor analysis and hierarchical clustering on principal components were performed to establish clusters of genotypes with similar behaviour. The rootstock candidates showed a very wide performance range compared to their parents. The trial allowed us to identify two very promising candidates (RG8 and RG10), whose registration as commercial rootstocks is already in progress.
Open Access
Alfalfa yield estimation using the combination of Sentinel-2 and meteorological data
(Elsevier, 2025-03-19) Gámez Guzmán, Angie Lorena; Segarra, Joel; Vatter, Thomas; Santesteban García, Gonzaga; Araus, José Luis; Aranjuelo Michelena, Iker; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Gobierno de Navarra / Nafarroako Gobernua
Context: Alfalfa (Medicago sativa L.) is one of the world's most important forages for livestock feeding. Timely yield estimates could provide information to guide management decisions to improve production. Since alfalfa crops typically undergo multiple harvests in a year and demonstrate rapid regrowth, satellite remote sensing techniques present a promising solution for alfalfa monitoring. Objective: To generate alfalfa yield estimation models at three phenological stages (early vegetative, late vegetative, and budding stages) using vegetation indices (VIs) derived from satellite Sentinel-2 images and their combination with meteorological data. Methods: We analyzed fields located in Navarre (northern Spain) over two consecutive seasons (2020 and 2021). To generate the yield estimation models, we applied a conventional multilinear regression and two machine learning algorithms (Least Absolute Shrinkage and Selection Operator - LASSO and Random Forest - RF). Results: Regardless of the statistical approach, the three phenological stages were not optimal when either VIs or meteorological data were used singularly as the predictor. However, the combination of VIs and meteorological data significantly improved the yield estimations, and in the case of LASSO model reached percentages of variance explained (R2) and normalized root mean square error (nRMSE) of R2= 0.61, nRMSE= 0.16 at the budding stage, but RF reached a R2= 0.44, nRMSE= 0.22 at the late vegetative stage, and R2= 0.36, nRMSE= 0.24 at the early vegetative stage. The most suitable variables identified were the minimum temperature, accumulated precipitation, the renormalized difference vegetation index (RDVI) and the normalized difference water index (NDWI). The RF model achieved more accurate yield estimations in early and late vegetative stages, but LASSO at bud stage. Conclusion: These models could be used for alfalfa yield estimations at the three phenological stages prior to harvest. The results provide an approach to remotely monitor alfalfa fields and can guide effective management strategies from the early development stages.
Open Access
Antifungal activity of chitosan/poly (ethylene oxide) blend electrospun polymeric fiber mat doped with metallic silver nanoparticles
(MDPI, 2023) Murillo Larrey, Leire; Rivero Fuente, Pedro J.; Sandúa Fernández, Xabier; Rodríguez Trías, Rafael; Pérez Garrido, María Gumersinda; Ingeniería; Ingeniaritza; Institute for Multidisciplinary Research in Applied Biology - IMAB; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, the implementation of advanced functional coatings based on the combination of two compatible nanofabrication techniques such as electrospinning and dip-coating technology have been successfully obtained for the design of antifungal surfaces. In a first step, uniform and beadless electrospun nanofibers of both polyethylene oxide (PEO) and polyethylene (PEO)/chitosan (CS) blend samples have been obtained. In a second step, the dip-coating process has been gradually performed in order to ensure an adequate distribution of silver nanoparticles (AgNPs) within the electrospun polymeric matrix (PEO/CS/AgNPs) by using a chemical reduction synthetic process, denoted as in situ synthesis (ISS). Scanning electron microscopy (SEM) has been used to evaluate the surface morphology of the samples, showing an evolution in average fiber diameter from 157 ± 43 nm (PEO), 124 ± 36 nm (PEO/CS) and 330 ± 106 nm (PEO/CS/AgNPs). Atomic force microscopy (AFM) has been used to evaluate the roughness profile of the samples, indicating that the ISS process induced a smooth roughness surface because a change in the average roughness Ra from 84.5 nm (PEO/CS) up to 38.9 nm (PEO/CS/AgNPs) was observed. The presence of AgNPs within the electrospun fiber mat has been corroborated by UV-Vis spectroscopy thanks to their characteristic optical properties (orange film coloration) associated to the Localized Surface Plasmon Resonance (LSPR) phenomenon by showing an intense absorption band in the visible region at 436 nm. Energy dispersive X-ray (EDX) profile also indicates the existence of a peak located at 3 keV associated to silver. In addition, after doping the electrospun nanofibers with AgNPs, an important change in the wettability with an intrinsic hydrophobic behavior was observed by showing an evolution in the water contact angle value from 23.4° ± 1.3 (PEO/CS) up to 97.7° ± 5.3 (PEO/CS/AgNPs). The evaluation of the antifungal activity of the nanofibrous mats against Pleurotus ostreatus clearly indicates that the presence of AgNPs in the outer surface of the nanofibers produced an important enhancement in the inhibition zone during mycelium growth as well as a better antifungal efficacy after a longer exposure time. Finally, these fabricated electrospun nanofibrous membranes can offer a wide range of potential uses in fields as diverse as biomedicine (antimicrobial against human or plant pathogen fungi) or even in the design of innovative packaging materials for food preservation.
Open Access
Assessing the efficiency of dimethylpyrazole-based nitrification inhibitors under elevated CO2 conditions
(Elsevier, 2021) Bozal-Leorri, Adrián; González Murua, Carmen; Marino Bilbao, Daniel; Aparicio Tejo, Pedro María; Corrochano Monsalve, Mario; Institute for Multidisciplinary Research in Applied Biology - IMAB
Nitrification inhibitors (NIs) are useful tools to reduce nitrogen (N) losses derived from fertilization in agriculture. However, it remains unclear whether a future climate scenario with elevated CO2 could affect NIs efficiency. Thus, the objective of this work was to study whether the increase of atmospheric CO2 concentration would affect the efficiency of two dimethylpyrazole-based NIs: 3,4-dimethylpyrazol phosphate (DMPP) and 3,4-dimethylpyrazol succinic acid (DMPSA) in a plant-soil microcosm. To do so, Hordeum vulgare var. Henley plants were grown in soil fertilized with ammonium sulphate (AS) with or without NIs under controlled environmental conditions at ambient CO2 (aCO(2)) or elevated CO2 (eCO(2); 700 ppm). In the soil, mineral nitrogen and N2O emission evolution were monitored together with nitrifying and denitrifying population that were quantified by qPCR. In the plant, biomass, total amino acid content and isotopic discrimination of N and C were measured. Both NIs showed greater efficiency to maintain soil NH4+ content under eCO(2) compared to aCO(2), as a consequence of 80% reduction of AOB abundance in eCO(2). Indeed, both inhibitors were able to lessen 53% the N2O emissions in eCO(2) compared to aCO(2). Regarding the plant, DMPP and DMPSA negatively affected plant biomass at aCO(2) but this effect was restored at eCO(2) due to a better ammonium tolerance associated with an increase in total amino acid content. Overall, DMPP and DMPSA NIs were highly efficient under eCO(2), reducing N2O emissions and keeping N in the soil stable for longer while maintaining plant biomass production.
Open Access
Assessing the evolution of wheat grain traits during the last 166 years using archived samples
(Nature Research, 2020) Mariem, S.B.; Gámez Guzmán, Angie Lorena; Larraya Reta, Luis María; Fuertes Mendizabal, Teresa; Cañameras, Nuria; Araus, José Luis; Aranjuelo Michelena, Iker; McGrath, Steve P.; Hawkesford, Malcolm J.; González Murua, Carmen; Gaudeul, Myriam; Medina, Leopoldo; Paton, Alan; Cattivelli, Luigi; Fangmeier, Andreas; Bunce, James; Tausz-Posch, Sabine; Macdonald, Andy J.; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Agronomía, Biotecnología y Alimentación
The current study focuses on yield and nutritional quality changes of wheat grain over the last 166 years. It is based on wheat grain quality analyses carried out on samples collected between 1850 and 2016. Samples were obtained from the Broadbalk Continuous Wheat Experiment (UK) and from herbaria from 16 different countries around the world. Our study showed that, together with an increase in carbohydrate content, an impoverishment of mineral composition and protein content occurred. The imbalance in carbohydrate/protein content was specially marked after the 1960’s, coinciding with strong increases in ambient [CO2] and temperature and the introduction of progressively shorter straw varieties. The implications of altered crop physiology are discussed.
Open Access
Assessing tree drought resistance and climate-growth relationships under different tree age classes in a pinus nigra arn. Ssp. salzmannii forest
(MDPI, 2021) Lucas Borja, Manuel Esteban; Bose, Arun K.; Andivia, Enrique; Candel Pérez, David; Plaza-Álvarez, Pedro A.; Linares, Juan C.; Institute for Multidisciplinary Research in Applied Biology - IMAB
The magnitude of drought impact in forest ecosystems depends on which group of trees are more severely affected; greater mortality of smaller trees can modulate the trajectories of succession, while the mortality of larger trees can disproportionately offset the ecosystem’s carbon balance. Several studies have documented a greater vulnerability of large trees to extreme droughts while some other studies reported a greater growth reduction in smaller trees during droughts. We tested these hypotheses by comparing tree basal area increment (BAI), drought resistance (i.e., magnitude of growth decline during drought), and resilience (i.e., magnitude of growth recovery after drought) across five different age-classes in black pine (Pinus nigra Arn. Ssp salzmannii) forests in Spain. Our results showed that the BAI patterns, drought resistance, and resilience were strongly influenced by tree age-classes. In addition, the effect of climatic water balance (precipitation minus potential evapotranspiration) on BAI significantly varied among age-classes. The effect of water balance on BAI was lower for younger age-classes (1–39 years of age) compared to older age-classes. We observed a greater growth reduction (i.e., lower resistance) in older trees (>40 years of age) during droughts compared to younger trees (<40 years of age). However, all trees, irrespective of their ages, were able to recover the growth rates after the drought. In general, younger trees showed a greater capacity in recovering the growth rate (i.e., more resilient) than older trees. We detected no significant effects of stand basal area and stand density on BAI, drought resistance, and resilience. Overall, our results indicated that growth of older trees was more negatively affected during drought. Therefore, these older/larger trees can be selected for commercial thinning, or can be released from competition, which can minimize the potential impacts of future droughts in black pine forests in Spain.
Open Access
Assessment of flesh browning diversity in apple germplasm collections phenotyped by image analysis
(ISHS, 2023) Miranda Jiménez, Carlos; Irisarri, Patricia; Arellano Zapatero, Julia; Bielsa, F. J.; Valencia Leoz, Ana; Urrestarazu Vidart, Jorge; Pina, Ana; Santesteban García, Gonzaga; Castel, L.; Errea, Pilar; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
Enzymatic flesh browning (EB) is one of the major problems affecting the quality and limiting the shelf life of minimally processed fruit. Traditionally, EB has been measured objectively using colourimeters. However, colourimeters are not suitable for phenotyping large quantities of fruit samples as they measure just one small area of a sample at a time, which hampers the acquisition of representative measurements and renders them time-consuming and costly. Previous research has shown that image analysis of digital photographs could be a viable alternative to obtain colour information of the entire surface of samples for large scale phenotyping, but to date there are no references for its practical application. The aim of this work was to assess the diversity in EB in a large set of cultivars phenotyped using digital photographs and a high-throughput analytical system based on image analysis developed by our team. A set of 143 cultivars from 104 genotypes, including modern references (16 cultivars) and traditional Spanish cultivars from UPNA (67 cultivars) and CITA (60 cultivars) germplasm collections was analysed in 2020 and 2021. The traditional cultivars were part of the core collection, which optimizes the representativeness of the genetic variation of apples preserved in Spanish collections. EB was evaluated in 10 fruits per cultivar and photographed at regular intervals from just after cutting to one hour later. A wide range of EB intensities was observed, with up to 20-fold differences between cultivars, which could be classified into five levels using two indices. The time at which EB was evaluated (30 or 60 min after slicing) had little influence on the classification. Traditional cultivars with low or very low EB were found to be comparable to those of references with less EB. The results show the potential of traditional germplasm to diversify the varietal offer and introduce new traits in apple breeding.
Open Access
AtCube: performing pathogen-root infection tests on Arabidopsis thaliana in a completely controlled way
(Elsevier, 2022) Poveda Arias, Jorge; Institute for Multidisciplinary Research in Applied Biology - IMAB
Arabidopsis thaliana represents the main model plant for the experimental analysis of plant genetics and developmental biology of photoautotrophic organisms, due to characteristics such as size, life cycle, fecundity, genetics and its easy experimental manipulation. In turn, A. thaliana is used as a model plant in plant-microorganism interaction studies, being of great importance in the knowledge of the form of infection of numerous plant pathogens. The present work is based on the development of an A. thaliana plant growth system in Phytatray II boxes and culture substrate, trying to establish a system that is free of contamination, completely controlled, self-sufficient, reproducible and standardized, called AtCube. Through the use of different necrotrophic and biotrophic/hemibiotrophic root-pathogens, bacteria, fungi and oomycetes, and the comparison with a conventional system of growth in plots, various results are analyzed on the effects of pathogens on plants and the advantages and differences of the AtCube system. This work makes it possible to highlight that the AtCube system represents a methodology that allows obtaining results similar to other systems but with important advantages regarding its standardization, rigor and reproducibility with respect to studies with A. thaliana and root pathogens. Furthermore, it could represent an equally efficient system in studies with other plant species and the application of foliar pathogens and/or beneficial microorganisms.
Open Access
Avances en el conocimiento sobre los organismos fitopatógenos y su repercusión en la Fitopatología en los últimos 35 años
(Phytoma España, 2023) Landa, Blanca B.; Cambra Álvarez, Mariano; Castillo, Pablo; Escobar Lucas, Carolina; García Arenal, Fernando; Jiménez Díaz, Rafael M.; López, María Milagros; Montesinos, Emilio; Murillo Martínez, Jesús; Pallás, Vicente; Palomares Rius, Juan Emilio; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
Los pasados 35 años han sido testigos de importantes avances en el conocimiento sobre los organismos fitopatógenos, demasiado numerosos y diversos en naturaleza para poder resumirlos en unas páginas. Muchos de dichos avances han estado mediados por el desarrollo de nuevas metodologías, instrumentos y protocolos de estudio, en particular los concernientes a las tecnologías de análisis y secuenciación del ADN que comenzaron con su amplificación mediada por una ADN polimerasa termoestable (PCR) ¿y sus posteriores derivados: PCR cuantitativa, en tiempo real, digital, etc. Estos avances continuaron con el uso de las plataformas de secuenciación masiva para el análisis de los genomas de estos organismos, incluso a partir de la matriz vegetal que infectaban sin necesidad de su aislamiento, así como el uso de diversas tecnologías -ómicas para el análisis masivo de la expresión diferencial de genes (genómica), proteínas (proteómica) y metabolitos (metabolómica). Todo ello ha tenido profundas repercusiones, por ejemplo, sobre la taxonomía y relaciones filogenéticas de estos organismos fitopatógenos, la comprensión de la regulación genética de la patogenicidad y de los factores (efectores) de virulencia, la resistencia a la infección en la planta. Asimismo, las tecnologías de observación microscópica y el uso de genes que codifican proteínas fluorescentes de diferentes propiedades espectrales han propiciado una mejor compresión de los procesos de infección (Deal, 2011). En las siguientes secciones del artículo se presentan algunos avances ilustrativos seleccionados por expertos para cada uno de los grandes grupos de organismos fitopatógenos: hongos, oomicetos, bacterias, virus y nematodos. Cabe decir que muchos de los avances presentados para cada organismo fitopatógeno son aplicables a todos los demás. Si bien, con objeto de no incurrir en reiteraciones, y extendernos en exceso, se ha intentado, en la medida de lo posible, seleccionar avances con aspectos diferenciadores.
Open Access
Bacillus thuringiensis Cyt proteins as enablers of activity of Cry and Tpp toxins against Aedes albopictus
(2023) Lai, Liliana; Villanueva, Maite; Muruzabal Galarza, Ane; Fernández González, Ana Beatriz; Unzue Pozas, Argiñe; Toledo Arana, Alejandro; Caballero Murillo, Primitivo; Caballero Sánchez, Carlos; Institute for Multidisciplinary Research in Applied Biology - IMAB
Aedes albopictus is a species of mosquito, originally from Southeast Asia, that belongs to the Culicidae family and the Dipteran insect order. The distribution of this vector has rapidly changed over the past decade, making most of the temperate territories in the world vulnerable to important human vector-borne diseases such as dengue, yellow fever, zika or chikungunya. Bacillus thuringiensis var. israeliensis (Bti)-based insecticides represent a realistic alternative to the most common synthetic insecticides for the control of mosquito larvae. However, several studies have revealed emerging resistances to the major Bti Crystal proteins such as Cry4Aa, Cry4Ba and Cry11Aa, making the finding of new toxins necessary to diminish the exposure to the same toxicity factors overtime. Here, we characterized the individual activity of Cyt1Aa, Cry4Aa, Cry4Ba and Cry11Aa against A. albopictus and found a new protein, Cyt1A-like, that increases the activity of Cry11Aa more than 20-fold. Additionally, we demonstrated that Cyt1A-like facilitates the activity three new Bti toxins: Cry53-like, Cry56A-like and Tpp36-like. All in all, these results provide alternatives to the currently available Bti products for the control of mosquito populations and position Cyt proteins as enablers of activity for otherwise non-active crystal proteins.
Open Access
Bacmid expression of granulovirus enhancin En3 accumulates in cell soluble fraction to potentiate nucleopolyhedrovirus infection
(MDPI, 2021) Ricarte Bermejo, Adriana; Simón de Goñi, Oihane; Fernández González, Ana Beatriz; Williams, Trevor; Caballero Murillo, Primitivo; Institute for Multidisciplinary Research in Applied Biology - IMAB
Enhancins are metalloproteinases that facilitate baculovirus infection in the insect midgut. They are more prevalent in granuloviruses (GVs), constituting up to 5% of the proteins of viral occlusion bodies (OBs). In nucleopolyhedroviruses (NPVs), in contrast, they are present in the envelope of the occlusion-derived virions (ODV). In the present study, we constructed a recombinant Autographa californica NPV (AcMNPV) that expressed the Trichoplusia ni GV (TnGV) enhancin 3 (En3), with the aim of increasing the presence of enhancin in the OBs or ODVs. En3 was successfully produced but did not localize to the OBs or the ODVs and accumulated in the soluble fraction of infected cells. As a result, increased OB pathogenicity was observed when OBs were administered in mixtures with the soluble fraction of infected cells. The mixture of OBs and the soluble fraction of Sf9 cells infected with BacPhEn3 recombinant virus was ~3- and ~4.7-fold more pathogenic than BacPh control OBs in the second and fourth instars of Spodoptera exigua, respectively. In contrast, when purified, recombinant BacPhEn3 OBs were as pathogenic as control BacPh OBs. The expression of En3 in the soluble fraction of insect cells may find applications in the development of virus-based insecticides with increased efficacy.
Open Access
Baculovirus expression and functional analysis of Vpa2 proteins from Bacillus thuringiensis
(MDPI, 2020) Simón de Goñi, Oihane; Palma Dovis, Leopoldo; Fernández González, Ana Beatriz; Williams, Trevor; Caballero Murillo, Primitivo; Institute for Multidisciplinary Research in Applied Biology - IMAB
The mode of action underlying the insecticidal activity of the Bacillus thuringiensis (Bt) binary pesticidal protein Vpa1/Vpa2 is uncertain. In this study, three recombinant baculoviruses were constructed using Bac-to-Bac technology to express Vpa2Ac1 and two novel Vpa2-like genes, Vpa2-like1 and Vpa2-like2, under the baculovirus p10 promoter in transfected Sf9 cells. Pairwise amino acid analyses revealed a higher percentage of identity and a lower number of gaps between Vpa2Ac1 and Vpa2-like2 than to Vpa2-like1. Moreover, Vpa2-like1 lacked the conserved Ser-Thr-Ser motif, involved in NAD binding, and the (F/Y)xx(Q/E)xE consensus sequence, characteristic of the ARTT toxin family involved in actin polymerization. Vpa2Ac1, Vpa2-like1 and Vpa2-like2 transcripts and proteins were detected in Sf9 culture cells, but the signals of Vpa2Ac1 and Vpa2-like2 were weak and decreased over time. Sf9 cells infected by a recombinant bacmid expressing Vpa2-like1 showed typical circular morphology and produced viral occlusion bodies (OBs) at the same level as the control virus. However, expression of Vpa2Ac1 and Vpa2-like2 induced cell polarization, similar to that produced by the microfilament-destabilizing agent cytochalasin D and OBs were not produced. The presence of filament disrupting agents, such as nicotinamide and nocodazole, during transfection prevented cell polarization and OB production was observed. We conclude that Vpa2Ac1 and Vpa2-like2 proteins likely possess ADP-ribosyltransferase activity that modulated actin polarization, whereas Vpa2-like1 is not a typical Vpa2 protein. Vpa2-like2 has now been designated Vpa2Ca1 (accession number AAO86513) by the Bacillus thuringiensis delta-endotoxin nomenclature committee.
Open Access
Beneficial effects of microbial volatile organic compounds (MVOCs) in plants
(Elsevier, 2021) Poveda Arias, Jorge; Institute for Multidisciplinary Research in Applied Biology - IMAB
Volatile organic compounds (VOCs) are chemical compounds whose saturation vapor pressures are greater than 102 kPa at 25 °C. Both plants and microorganisms produce VOCs that allow them to communicate intra- and inter-specifically. By emitting VOCs, plants defend themselves against herbivores and pathogens, warn their neighbors of the attack, compete with other plants, and/or feed microbial populations. Microorganisms emit VOCs to communicate or attack each other. Microbial VOCs (MVOCs) can be of great benefit to plants and their use in agriculture thanks to their ability to inhibit the growth and development of plant pathogens, induce the activation of plant defenses, or promote plant growth and development. In recent years, advances in understanding the importance of microbial volatilome have placed MVOCs as important biotechnological resources in plant production systems.
Open Access
Can ammonium stress be positive for plant performance?
(Frontiers Media, 2019) Marino Bilbao, Daniel; Morán Juez, José Fernando; Institute for Multidisciplinary Research in Applied Biology - IMAB
In this article, we propose a change of paradigm where ammonium nutrition may be considered not exclusively as an undesirable situation for plant performance, but as a way to provoke changes in plant metabolism that can be beneficial for crop quality and plant physiology. While some of the positive effects of ammonium referred here still require further evaluation, the cross-tolerance induction of NH+4 to certain subsequent stresses, notably salinity, is clear. However, the molecular actors governing these interactions are almost completely unknown, and future works will be essential in order to fully exploit the benefits of ammonium-based fertilizers.