Open Access
Microorganisms as biocontrol agents against bacterial citrus diseases
(Elsevier, 2021) Poveda Arias, Jorge; Roeschlin, Roxana Andrea; Marano, María Rosa; Favaro, María Alejandra; Institute for Multidisciplinary Research in Applied Biology - IMAB
Citrus represents one of the most widely grown crops on the planet, extensively cultivated for both the fresh fruit and juice markets. The productivity of citrus orchards can be seriously affected by highly aggressive pathogenic bacteria, such as Xanthomonas citri subsp. citri, Xylella fastidiosa subsp. pauca and currently Candidatus Liberibacter asiaticus. Different microbiological biocontrol agents have been described against these pathogens, such as antagonistic bacteria (mainly species from Pseudomonas and Bacillus genus) and bacteriophages. This review summarizes all the microbiological control strategies reported so far against bacterial diseases that affect citrus, highlighting those fields of study where there is great potential yet to be discovered.
Open Access
Overview of the use of biochar from main cereals to stimulate plant growth
(Carnegie Institution por Science, 2022) Martínez Gómez, Ángela; Poveda Arias, Jorge; Escobar, Carolina; Institute for Multidisciplinary Research in Applied Biology - IMAB
The total global food demand is expected to increase up to 50% between 2010 and 2050; hence, there is a clear need to increase plant productivity with little or no damage to the environment. In this respect, biochar is a carbon-rich material derived from the pyrolysis of organic matter at high temperatures with a limited oxygen supply, with different physicochemical characteristics that depend on the feedstock and pyrolysis conditions. When used as a soil amendment, it has shown many positive environmental effects such as carbon sequestration, reduction of greenhouse gas emissions, and soil improvement. Biochar application has also shown huge benefits when applied to agri-systems, among them, the improvement of plant growth either in optimal conditions or under abiotic or biotic stress. Several mechanisms, such as enhancing the soil microbial diversity and thus increasing soil nutrient-cycling functions, improving soil physicochemical properties, stimulating the microbial colonization, or increasing soil P, K, or N content, have been described to exert these positive effects on plant growth, either alone or in combination with other resources. In addition, it can also improve the plant antioxidant defenses, an evident advantage for plant growth under stress conditions. Although agricultural residues are generated from a wide variety of crops, cereals account for more than half of the world¿s harvested area. Yet, in this review, we will focus on biochar obtained from residues of the most common and relevant cereal crops in terms of global production (rice, wheat, maize, and barley) and in their use as recycled residues to stimulate plant growth. The harvesting and processing of these crops generate a vast number and variety of residues that could be locally recycled into valuable products such as biochar, reducing the waste management problem and accomplishing the circular economy premise. However, very scarce literature focused on the use of biochar from a crop to improve its own growth is available. Herein, we present an overview of the literature focused on this topic, compiling most of the studies and discussing the urgent need to deepen into the molecular mechanisms and pathways involved in the beneficial effects of biochar on plant productivity.
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
Control of postharvest diseases in berries through edible coatings and bacterial probiotics
(Elsevier, 2022) Romero, Janira; Albertos, Irene; Díez Méndez, Alexandra; Poveda Arias, Jorge; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The world's population is growing, which requires more resources, including food. Some necessary foods, such as berries, are very perishable fresh products that suffer contamination by pathogens, generating great economic losses. Various physical and chemical strategies have been used to mitigate these losses over the years, including the use of pesticides. However, the negative impact on the environment and human health of these chemical products has aroused interest in the development of other control methods. Biocontrol is one of these innovative strategies, in which various biological control agents can be used, including bacteria probiotics. Probiotics act as antagonists of fungal pathogens by competition for space and nutrients, production of secondary metabolites, such as volatile organic compounds (VOCs), lytic enzymes, and activation of plant defenses. On the other hand, there are materials in which protection against pathogens has been seen, such as edible coatings, since they have components, such as chitosan, with antimicrobial properties. In addition, probiotics can be used in conjunction with other elements such as edible coatings, resulting from a new control strategy against post-harvest diseases. This review compiles studies that use probiotics and/or edible coatings as a method of reducing post-harvest diseases, specifically, in berries.
Open Access
Endophytic fungi as direct plant growth promoters for sustainable agricultural production
(Springer, 2021) Poveda Arias, Jorge; Eugui Arrizabalaga, Daniel; Abril Urías, Patricia; Velasco, Pablo; Institute for Multidisciplinary Research in Applied Biology - IMAB
Current rates of population growth require the development of new agricultural strategies to feed the world human and livestock. The massive use of agricultural chemicals causes serious damage to the environment, and to human and animal health. For this reason, the use of endophytic fungi represents a biological alternative in increasing agricultural productivity in a sustainable way. This group of microorganisms, which inhabit plant tissues and organs without causing symptoms of damage, includes a great diversity of filamentous fungi and yeasts that are capable of increasing agricultural productivity. Some of the mechanisms involved in promoting plant growth by means of endophytic fungi include the increasing access to nutrients (nitrogen, phosphorus, potassium, zinc, iron, etc.), production of plant hormones, the ethylene amount reduction, or increase in water acquisition rate. This review tries to compile all the works carried out in the last decades on endophytic fungi use as plant growth promoters with great potential in agriculture.
Open Access
The Pbo cluster from Pseudomonas syringae pv. phaseolicola NPS3121 is thermoregulated and required for phaseolotoxin biosynthesis
(MDPI, 2021) Guardado-Valdivia, Lizeth; Chacón-López, Alejandra; Murillo Martínez, Jesús; Poveda Arias, Jorge; Hernández Flores, José Luis; Xoca-Orozco, Luis; Aguilera, Selene; Institute for Multidisciplinary Research in Applied Biology - IMAB
The bean (Phaseolus vulgaris) pathogen Pseudomonas syringae pv. phaseolicola NPS3121 synthe-sizes phaseolotoxin in a thermoregulated way, with optimum production at 18 °C. Gene PSPPH_4550 was previously shown to be thermoregulated and required for phaseolotoxin bio-synthesis. Here, we established that PSPPH_4550 is part of a cluster of 16 genes, the Pbo cluster, included in a genomic island with a limited distribution in P. syringae and unrelated to the posses-sion of the phaseolotoxin biosynthesis cluster. We identified typical non-ribosomal peptide syn-thetase, and polyketide synthetase domains in several of the pbo deduced products. RT-PCR and the analysis of polar mutants showed that the Pbo cluster is organized in four transcriptional units, including one monocistronic and three polycistronic. Operons pboA and pboO are both es-sential for phaseolotoxin biosynthesis, while pboK and pboJ only influence the amount of toxin produced. The three polycistronic units were transcribed at high levels at 18 °C but not at 28 °C, whereas gene pboJ was constitutively expressed. Together, our data suggest that the Pbo cluster synthesizes secondary metabolite(s), which could participate in the regulation of phaseolotoxin biosynthesis.
Open Access
Filamentous fungi as biocontrol agents in olive (Olea europaea L.) diseases: mycorrhizal and endophytic fungi
(Elsevier, 2021) Poveda Arias, Jorge; Baptista, Paula; Institute for Multidisciplinary Research in Applied Biology - IMAB
Olive (Olea europaea) is a crop of great agronomic, economic and cultural interest for the Mediterranean Basin, although the increase in world demand for olive oil is expanding its cultivation by other countries in the southern hemisphere. The main olive pathogens include bacteria (Pseudomonas savastanoi pv. savastanoi, Xylella fastidiosa), fungi (Colletotrichum spp., Verticillium dahliae, Fusarium spp. Rhizoctonia solani), oomycetes (Phytophthora spp.) and nematodes (Meloidogyne spp.). To combat these pathogens, different biocontrol strategies have been developed with bacteria and yeasts, although its capacity for establishment in the field entails several difficulties. In this sense, filamentous fungi represent an efficient and effective alternative in the control of the different pathogens of the olive tree. The present review compiles all the studies existing so far in the biocontrol of these pathogens through the use of mycorrhizal and endophytic filamentous fungi, making a separate section for the genus Trichoderma due to the special interest that their use has generated. The mechanisms used by these fungi include competition for space and nutrients, parasitism, antibiosis or activation of the plant's defensive responses, among others.
Open Access
Editorial: Beneficial effects of fungal endophytes in major agricultural crops
(Frontiers Media, 2022) Poveda Arias, Jorge; Baptista, Paula; Sacristán, Soledad; Velasco, Pablo; Institute for Multidisciplinary Research in Applied Biology - IMAB
Endophytic microorganisms are those that can dwell within plant tissues without any external sign of infection or other harmful effects on the host plants (Burragoni and Jeon, 2021). In recent decades, the important role that both bacterial and fungal endophytes play in plant growth and development, as well as in their ability to survive in their environment, has been identified (Burragoni and Jeon, 2021). Endophytic fungi can be found colonizing any plant organ, presenting a very different distribution and diversity among plants of different species, among plants of the same species, and even among organs of the same plant (Aamir et al., 2020). In crops, endophytic fungi act through different beneficial pathways, as biofertilizers promoting plant growth, as biological control agents of pathogens and pests or as inducers of tolerance under abiotic stresses, having great importance in the development of new strategies for sustainable agriculture (Aamir et al., 2020). These benefits for crops have been studied in the papers published in this Research Topic: promotion of plant growth in tomato (Paradza et al.), cotton (Silva et al.) and wheat (Asim et al.), increased tolerance under salt stress in tritordeum and perennial ryegrass (Toghueo et al.), as biological control agents against pathogenic fungi through antibiosis and mycoparasitism (Silva et al.), or as insecticidal agents through activation of systemic plant defenses (Paradza et al.; Agbessenou et al.), among others.
Open Access
Broccoli (Brassica oleracea var. italica) biomass as a resource for obtaining glucosinolate extracts to control postharvest fungal diseases
(Springer, 2025-05-27) Eugui Arrizabalaga, Daniel; Fernández San Millán, Alicia; Velasco, Pablo; Veramendi Charola, Jon; Rodríguez, Víctor Manuel; Poveda Arias, Jorge; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
Broccoli (Brassica oleracea var. italica) is a crop of great agronomic and economic importance worldwide. Because its edible parts are the inflorescences, large quantities of non-commercial biomass are produced each year in the field and in the food industry. In order to develop a circular economy around the broccoli crop, the present work develops glucosinolates (GSL) extracts with antimicrobial capacity for postharvest use in tomato, apple and table white grape against fungal diseases produced by the pathogens Botrytis cinerea, Alternaria alternata and Penicillium expansum. GSL extracts from organic crop management reported a higher content of GSLs than conventional management. These extracts are not effective in the control of A. alternata and P. expansum, possibly due to the absence of sinigrin. Furthermore, the extracts were ineffective in the control of B. cinerea on table white grapes, possibly due to the non-climacteric fruit condition and an absence in the induction of ethylene-mediated plant defenses. However, intact GSL extracts were effective in controlling B. cinerea on apple, while the addition of myrosinase enzyme caused effectiveness also on tomato and apple. Therefore, obtaining GSL extracts with biopesticidal capacity against B. cinerea in postharvest could be a circular economy strategy for broccoli agriculture and industry.
Open Access
Agronomic and metabolomic side-effects of a divergent selection for indol-3-ylmethylglucosinolate content in kale (Brassica oleracea var. acephala)
(MDPI, 2021) Poveda Arias, Jorge; Velasco, Pablo; Haro, Antonio de; Johansen, Tor J.; McAlvay, Alex C.; Möllers, Christian; Mølmann, Jorgen A.B.; Ordiales, Elena; Rodríguez, Víctor Manuel; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
Brassica oleracea var. acephala (kale) is a cruciferous vegetable widely cultivated for its leaves and flower buds in Europe and a food of global interest as a 'superfood'. Brassica crops accumulate phytochemicals called glucosinolates (GSLs) which play an important role in plant defense against biotic stresses. Studies carried out to date suggest that GSLs may have a role in the adaptation of plants to different environments, but direct evidence is lacking. We grew two kale populations divergently selected for high and low indol-3-ylmethylGSL (IM) content (H-IM and L-IM, respectively) in different environments and analyzed agronomic parameters, GSL profiles and metabolomic profile. We found a significant increase in fresh and dry foliar weight in H-IM kale populations compared to L-IM in addition to a greater accumulation of total GSLs, indole GSLs and, specifically, IM and 1-methoxyindol-3-ylmethylGSL (1MeOIM). Metabolomic analysis revealed a significant different concentration of 44 metabolites in H-IM kale populations compared to L-IM. According to tentative peak identification from MS interpretation, 80% were phenolics, including flavonoids (kaempferol, quercetin and anthocyanin derivates, including acyl flavonoids), chlorogenic acids (esters of hydroxycinnamic acids and quinic acid), hydroxycinnamic acids (ferulic acid and p-coumaric acid) and coumarins. H-IM kale populations could be more tolerant to diverse environmental conditions, possibly due to GSLs and the associated metabolites with predicted antioxidant potential.