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
Glucosinolate-extracts from residues of conventional and organic cultivated broccoli leaves (brassica oleracea var. italica) as potential industrially-scalable efficient biopesticides against fungi, oomycetes and plant parasitic nematodes
(Elsevier, 2023) Eugui Arrizabalaga, Daniel; Velasco, Pablo; Abril Urías, Patricia; Escobar, Carolina; Gómez-Torres, Óscar; Caballero, Sara; Poveda Arias, Jorge; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
This study aimed to standarize a protocol for obtaining a bioactive extract from broccoli (Brassica oleracea var. italica) crop residues, that is suitable for application on an industrial scale and effective in reducing plant disease incidence. For this purpose, the influence of several extraction factors in the glucosinolate (GSL) content was studied with leaves collected from two conventional broccoli fields and two organic broccoli fields. The analysis showed that lyophilization had no influence on the GSL content. Storage of plant material under two different temperatures (− 20ºC and − 80ºC) had no influence on the GSLs content of the extracts. Phytotoxicity of the extracts was studied with six different plant seeds, and also cytotoxicity was determined with human liver cells in vitro. The extracts were phytotoxic at dilutions above 10%, while cell toxicity was low. Extracts concentrations of 0.1%, 1% and 2% were tested in vitro against eight plant pathogenic fungi and two oomycetes in solid and in liquid media. The extracts reduced the growth of several plant pathogenic fungi at 2% dilution by up to 38.37% against Alternaria alternata and up to 46.55% against Sclerotinia sclerotiorum. When combined with myrosinase enzyme the effect of the extracts was enhanced, reaching inhibition values of 67.06% against A. alternata in solid medium and 68.52% against Rhizoctonia solani in liquid medium. In contrast, the same extracts increased the growth of the plant pathogenic oomycetes Pythium ultimum and Phytophthora cactorum. The effect of the same extracts in the free leaving larvae, J2s, of the plant-parasitic nematode (PPN) Meloidogyne javanica was not obvious. Minor significant differences were obtained but with no clear dose-response in nematode mortality, and no inhibition of eggs hatching was observed. These results show the industrial potential of using broccoli residues to obtain extracts with biopesticide activity against plant pathogenic fungi.
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
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
Deciphering plant health status: the link between secondary metabolites, fungal community and disease incidence in olive tree
(Frontiers Media, 2023) Gomes, Teresa; Pereira, José Alberto; Moya-Laraño, Jordi; Poveda Arias, Jorge; Lino-Neto, Teresa; Baptista, Paula; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Plant-associated microorganisms are increasingly recognized to play key roles in host health. Among several strategies, associated microorganisms can promote the production of specific metabolites by their hosts. However, there is still a huge gap in the understanding of such mechanisms in plant-microorganism interaction. Here, we want to determine whether different levels of olive leaf spot (OLS) disease incidence were related to differences in the composition of fungal and secondary metabolites (i.e. phenolic and volatile compounds) in leaves from olive tree cultivars with contrasting OLS susceptibilities (ranging from tolerant to highly susceptible). Accordingly, leaves with three levels of OLS incidence from both cultivars were used to assess epiphytic and endophytic fungal communities, by barcoding of cultivable isolates, as well as to evaluate leaf phenolic and volatile composition. Fungal and metabolite compositions variations were detected according to the level of disease incidence. Changes were particularly noticed for OLS-tolerant cultivars, opposing to OLS-susceptible cultivars, suggesting that disease development is linked, not only to leaf fungal and metabolite composition, but also to host genotype. A set of metabolites/fungi that can act as predictive biomarkers of plant tolerance/susceptibility to OLS disease were identified. The metabolites ¿-farnesene and p-cymene, and the fungi Fusarium sp. and Alternaria sp. were more related to disease incidence, while Pyronema domesticum was related to the absence of disease symptoms. Cultivar susceptibility to OLS disease is then suggested to be driven by fungi, volatile and phenolic host leaves composition, and above all to plant-fungus interaction. A deeper understanding of these complex interactions may unravel plant defensive responses.
Open Access
Mechanisms involved in drought stress tolerance triggered by rhizobia strains in wheat
(Frontiers Media, 2022) Barquero, Marcia; Poveda Arias, Jorge; Laureano Marín, Ana M.; Ortiz Liébana, Noemí; Brañas, Javier; González Andrés, Fernando; Institute for Multidisciplinary Research in Applied Biology - IMAB
Rhizobium spp. is a well-known microbial plant biostimulant in non-legume crops, but little is known about the mechanisms by which rhizobia enhance crop productivity under drought stress. This work analyzed the mechanisms involved in drought stress alleviation exerted by Rhizobium leguminosarum strains in wheat plants under water shortage conditions. Two (LBM1210 and LET4910) of the four R. leguminosarum strains significantly improved the growth parameters (fresh and dry aerial weight, FW and DW, respectively), chlorophyll content, and relative water content (RWC) compared to a non-inoculated control under water stress, providing values similar to or even higher for FW (+4%) and RWC (+2.3%) than the non-inoculated and non-stressed control. Some other biochemical parameters and gene expression explain the observed drought stress alleviation, namely the reduction of MDA, H2O2 (stronger when inoculating with LET4910), and ABA content (stronger when inoculating with LBM1210). In agreement with these results, inoculation with LET4910 downregulated DREB2 and CAT1 genes in plants under water deficiency and upregulated the CYP707A1 gene, while inoculation with LBM1210 strongly upregulated the CYP707A1 gene, which encodes an ABA catabolic enzyme. Conversely, from our results, ethylene metabolism did not seem to be involved in the alleviation of drought stress exerted by the two strains, as the expression of the CTR1 gene was very similar in all treatments and controls. The obtained results regarding the effect of the analyzed strains in alleviating drought stress are very relevant in the present situation of climate change, which negatively influences agricultural production.
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
Combined use of Trichoderma and beneficial bacteria (mainly Bacillus and Pseudomonas): development of microbial synergistic bio-inoculants in sustainable agriculture
(Elsevier, 2022) Poveda Arias, Jorge; Eugui Arrizabalaga, Daniel; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
Agriculture nowadays is facing many challenges, with among the most important to be able to feed the increasing human population through more sustainable and environmentally friendly production. In this context, the use of microorganisms has been extensively studied, both with fungi such as Trichoderma spp. and with bacteria, such as Bacillus spp. or Pseudomonas spp. While inoculation with these microorganisms has a positive effect on crops, their combination offers even greater potential as plant growth promoters and as biocontrol agents, with diverse mechanisms that are thoroughly considered in this review. Synergies between Trichoderma and bacteria cause more benefits than the sum of their parts, and this makes them a promising alternative for managing crops and controlling diseases or pests in modern agriculture. However, more studies are needed to determine the specific mechanisms of this synergistic effect in certain lines of research, since there is extensive data about their use as plant growth promoters or biocontrol agents against diseases and certain pests, but little or no information is available about their use against diseases caused by viruses or the effect on plant tolerance to abiotic stresses.
Open Access
Effect of volatile and non-volatile metabolites from Leptosphaeria maculans on tomato calli under abiotic stresses
(Global Science Books, 2022) Poveda Arias, Jorge; Institute for Multidisciplinary Research in Applied Biology - IMAB
Drought and salinity can be serious problems for agricultural productivity in certain planet areas. Leptosphaeria maculans is the causative agent of the blackleg in crucifer plants. In this work, a novel methodology for studying the effects of fungal metabolites (volatile and non-volatile) on plant calli in the presence of abiotic stresses is presented, by using L. maculans, tomato calli, and drought and salinity stresses. In this way, this study has reported how, under salinity and drought stresses, the growth and vitality of tomato calli is inhibited, increasing its tissues-oxidation and accumulation of ROS. By applying metabolites from L. maculans, the growth of calli treated with non-volatile metabolites showed and increment under salinity and drought conditions. On the other hand, calli treated with volatile metabolites showed an increment in tissues-vitality under salinity and drought conditions. A series of gene expression analysis was also conducted in order to determine the performance of related genes. Results of this study showed that growth related gene expression was induced, together with abiotic stress tolerance gene in response to abscisic acid, AREB1. In addition, the application of volatile metabolites from L. maculans on tomato calli without abiotic stresses increases its growth and vitality, and reduces its oxidation and accumulation of ROS, in accordance with the results of gene expression obtained. The ability of L. maculans metabolites to increase plant tolerance to abiotic stresses could be related to their ability to produce volatile and non-volatile-metabolites, which induce the antioxidant enzyme activity or accumulation of antioxidant compounds, or their ability to increase the expression of ABA-dependent response genes to abiotic stresses.
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.