Publicaciones
2024
1. Javier Ortiz, Nathalia Dias, Roxana Alvarado, Javiera Soto, Tedy Sanhueza, Claudia Rabert, Milko Jorquera, Cesar Arriagada, C. 2024. N- acyl homoserine lactones (AHLs) type signal molecules produced by rhizobacteria associated with plants that growing in a metal(oids) contaminated soil: A catalyst for plant growth. Microbiological Research, 127606 (WOS. Impact Factor 6.7 Q1). https://doi.org/10.1016/j.micres.2024.127606
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2. Alejandra Fuentes-Quiroz, Hector Herrera, Roxana Alvarado, Claudia Rabert, Cesar Arriagada, Rafael Borges da Silva Valadares. 2024. Functional differences of cultivable leaf-associated microorganisms in the native Andean tree Gevuina avellana Mol. (Proteaceae) exposed to atmospheric contamination. Journal of Applied Microbiology, 2024, 135, lxae041 (WOS. Impact Factor 4.0 Q1). https://doi.org/10.1093/jambio/lxae041.
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3. Javiera Soto, Tedy Sanhueza, Javier Ortiz, María de la Luz Mora, Inmaculada Garcia-Romera, César Arriagada. 2024. Plant growth-promotion and abiotic stress tolerance of dark septate endophyte fungi isolated from roots of native Andean Ericaceae plants colonizing volcanic deposits in southern Chile. Journal of Soil Science and Plant Nutrition. 24:5144–5153 (WOS. Impact Factor 3.9 Q2). https://doi.org/10.1007/s42729-024-01898-4
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4. Roxana Alvarado, Cesar Arriagada-Escamilla, Javier Ortiz, Reinaldo Campos-Vargas, Pablo Cornejo. 2024. Alginate–Bentonite Encapsulation of Extremophillic Bacterial Consortia Enhances Chenopodium quinoa Tolerance to Metal Stress. Microorganisms. 2024, 12, 2066. https://doi.org/10.3390/microorganisms12102066 (WOS. Impact Factor
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Laboratorio de Biorremediación
Departamento de Cs. Forestales
Universidad de La Frontera
Avenida Francisco Salazar 01145
Temuco, Chile
Casilla 54-D
Author Full Names:
Javier Ortiz, Nathalia Dias, Roxana Alvarado, Javiera Soto, Tedy Sanhueza, Claudia Rabert, Milko Jorquera, César Arriagada
Source Title: Microbiological Research
The present study explores the potential of rhizobacteria isolated from Baccharis linearis and Solidago chilensis in metal(loid)-contaminated soil for producing N-acyl-homoserine lactones (AHLs)-type signal molecules and promoting plant growth. A total of 42 strains were isolated, four demonstrating the production of AHL-type signal molecules. Based on 16S rRNA gene sequencing analyses and MALDI-TOF analyses, these four isolates were identified as belonging to the Pseudomonas genus, specifically P. brassicacearum, P. frederickberguensis, P. koreensis, and P. orientalis. The four AHL-producing strains were evaluated for metal(loid)s tolerance, their plant growth promotion traits, AHL quantification, and their impact on in vitro Lactuca sativa plant growth. The study found that four strains exhibited high tolerance to metal(loid)s, particularly As, Cu, and Zn. Additionally, plant growth-promoting traits were detected in AHL-producing bacteria, such as siderophore production, ammonia production, ACC deaminase activity, and P solubilization. Notably, AHL production varied among strains isolated from B. linearis, where C7-HSL and C9-HSL signal molecules were detected, and S. chilensis, where only C7-HSL signal molecules were observed. In the presence of copper, the production of C7- HSL and C9-HSL significantly decreased in B. linearis isolates, while in S. chilensis isolates, C7-HSL production was inhibited. Further, when these strains were inoculated on lettuce seeds and in vitro plants, a significant increase in germination and plant growth was observed. Mainly, the inoculation of P. brassicacearum and P. frederickberguensis led to extensive root hair development, significantly increasing length and root dry weight. Our results demonstrate that rhizospheric strains produce AHL molecules and stimulate plant growth, primarily through root development. However, the presence of copper reduces the production of these molecules, potentially affecting the root development of non-metalloid tolerant plants such as S. chilensis, which would explain its low population in this hostile environment.
https://doi.org/10.1016/j.micres.2024.127606
Author Full Names:
Alejandra Fuentes-Quiroz, Hector Herrera, Roxana Alvarado, Claudia Rabert, Cesar Arriagada, Rafael Borges da Silva Valadares
Source Title: Journal of Applied Microbiology
This study aimed to evaluate and describe the functional differences of cultivable bacteria and fungi inhabiting the leaves of Gevuina avellana Mol. (Proteaceae) in an urban area with high levels of air pollution and in a native forest in the southern Andes.
Phyllosphere microorganisms were isolated from the leaves of G. avellana, their plant growth-promoting capabilities were estimated along with their biocontrol potential and tolerance to metal(loid)s. Notably, plants from the urban area showed contrasting culturable leaf-associated microorganisms compared to those from the native area. The tolerance to metal(loid)s in bacteria range from 15 to 450 mg l−1 of metal(loid)s, while fungal strains showed tolerance from 15 to 625 mg l−1, being especially higher in the isolates from the urban area. Notably, the bacterial strain Curtobacterium flaccumfaciensand the fungal strain Cladosporium sp. exhibited several plant-growth-promoting properties along with the ability to inhibit the growth of phytopathogenic fungi.
Overall, our study provides evidence that culturable taxa in G. avellana leaves is directly influenced by the sampling area. This change is likely due to the presence of atmospheric pollutants and diverse microbial symbionts that can be horizontally acquired from the environment.
https://doi.org/10.1093/jambio/lxae041
Author Full Names: Lagos, Claudio; Larsen, John; Fuentes, Alejandra; Herrera, Hector; Garcia-Romera, Inmaculada; Campos-Vargas, Reinaldo; Arriagada, Cesar
Source Title: AGRONOMY-BASEL
Polycyclic aromatic hydrocarbons (PAHs) are strong toxic compounds mainly released to the environment during combustion of fossil fuels, and have strong toxic effects on living organisms, with soil being one of their main reservoirs. High PAH levels in soils can interfere with plant growth and biomass production, causing several losses of diversity. In this study, we evaluated the effects of the co-inoculation of Trichoderma viride and Funneliformis mosseae on PAH dissipation and alleviation of oxidative stress in Triticum aestivum L. (wheat) plants growing in a phenanthrene-spiked soil. We determined the effect of single and dual fungal inoculation on phenanthrene dissipation rates, soil enzyme activities, dry biomass, antioxidant enzymes, lipid peroxidation, and organic acid exudation of plants growing in a soil spiked with phenanthrene at 500 and 1000 mg kg(-1) soil. The coinoculation with T. viride and F. mosseae resulted in a high phenanthrene dissipation from the soil. Also, dry biomass, soil enzymes, antioxidant response, organic acid exudation and phenanthrene content in roots were increased by the dual inoculation treatments, whereas lipid peroxidation and phenanthrene content in shoots were reduced. Our results show that the co-inoculation with these two soil fungi significantly promotes phenanthrene dissipation from soil and contributes to alleviating oxidative damage in wheat plants exposed to high levels of phenanthrene.
DOI: 10.3390/agronomy11030411
UT (Unique WOS ID): WOS:000633185500001
Author Full Names: Lagos, Claudio A.; Diaz, Tsiri; Saucedo, Estefania; Arriagada, Cesar; Larsen, John; Jaramillo-Lopez, Pablo F.
Source Title: RHIZOSPHERE
Soil pollution with polycyclic aromatic hydrocarbons (PAH) such as phenanthrene is extremely detrimental to the environment and to all living organisms, which is why appropriate remediation techniques are required. Here we tested single and combination effects of the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis BEG 87 and a soil amendment that results from the fermentation of organic matter through the activity of efficient microorganisms (Bokashi) on maize (Zea mays L.) growth performance, when exposed to phenanthrene. Main results showed that phenanthrene reduced total maize dry biomass, though only in mycorrhizal plants. The AMF root colonization respectively increased and decreased with Bokashi and phenanthrene. Growth suppressions in maize with AMF are common, but to our knowledge this has not been shown in combination with PAH. Possible mechanisms involved in this growth suppression could be related with increased phenanthrene uptake and hence increased plant toxicity or that phenanthrene impaired possible benefits from AMF in terms of nutrient acquisition, which could have resulted in the imbalance of the cost-benefit of the mycorrhizal association leading to growth suppression. However, the underlying mechanisms for this observed negative mycorrhiza growth response in maize when exposed to phenanthrene remains to be identified.
UT (Unique WOS ID): WOS:000663433200005
DOI: 10.1016/j.rhisph.2021.100340
Author Full Names: Javiera Soto, Tedy Sanhueza, Javier Ortiz, María de la Luz Mora, Inmaculada Garcia-Romera, César Arriagada
Source Title: Journal of Soil Science and Plant Nutrition
Purpose. This study aimed to isolate and assign at genus level the dark septate endophytes (DSE) that colonize native Ericaceae plants in the Andes Mountains of southern Chile and evaluate their plant growth-promotion traits and their in vitro tolerance to abiotic stress.
Methods. We isolated, identified, and evaluated the characteristics of five DSE, Pezizomycotina sp, Alternaria sp.1, Phialocephala sp., Alternariasp.2, Cladosporium sp. The DSE’s plant growth-promoting capabilities were assessed, encompassing their capacity to produce indoleacetic acid (IAA), phosphate solubilization, ammonia and siderophores. Additionally, their potential to enhance stress tolerance was evaluated through the production of exopolysaccharides (EPS) and ACC deaminase. Moreover, the DSE’s ability to tolerate aluminum and water stress was evaluated.
Results. Alternaria sp.1, Alternaria sp.2 and Cladosporium sp. produce higher concentrations of IAA and ammonium (4.59 mg L-1 and 17.66 µmol mL-1; 9.87 mg L-1 and 24.37 µmol mL-1; 4.11 mg L-1 and 36.28 µmol mL-1, respectively), while Cladosporium sp. was able to solubilize phosphate from iron, aluminum and phytic acid sources. Cladosporium sp. produces the highest concentration of EPS (245 mg L-1). Phialocephala sp. tolerated the highest aluminum concentration (500 mg L-1) and water stress induced by PEG-6000, along with Cladosporiumsp.
Conclusion. We found that the dark septate endophytic fungi isolated from native Andean Ericaceae plants colonizing volcanic deposits in southern Chile possess unique characteristics that enable them to tolerate aluminum and water stress, making them ideal plant growth promoters in stressful environments. They could potentially play a crucial role in adapting plants to challenging environments and contribute to sustainable agriculture practices in this regionhttps://doi.org/10.1007/s42729-024-01898-4
Author Full Names:
Roxana Alvarado, Cesar Arriagada-Escamilla, Javier Ortiz, Reinaldo Campos-Vargas, Pablo Cornejo
Source Title: Microorganisms
This study explores the encapsulation in alginate/bentonite beads of two metal(loid)- resistant bacterial consortia (consortium A: Pseudomonas sp. and Bacillus sp.; consortium B: Pseu- domonas sp. and Bacillus sp.) from the Atacama Desert (northern Chile) and Antarctica, and their influence on physiological traits of Chenopodium quinoa growing in metal(loid)-contaminated soils. The metal(loid) sorption capacity of the consortia was determined. Bacteria were encapsulated using ionic gelation and were inoculated in soil of C. quinoa. The morphological variables, photosynthetic pigments, and lipid peroxidation in plants were evaluated. Consortium A showed a significantly higher biosorption capacity than consortium B, especially for As and Cu. The highest viability of consortia was achieved with matrices A1 (3% alginate and 2% bentonite) and A3 (3% alginate, 2% bentonite and 2.5% LB medium) at a drying temperature of 25 ◦C and storage at 4 ◦C. After 12 months, the highest viability was detected using matrix A1 with a concentration of 106 CFU g−1. Further, a greenhouse experiment using these consortia in C. quinoa plants showed that, 90 days after inoculation, the morphological traits of both consortia improved. Chemical analysis of metal(loid) contents in the leaves indicated that consortium B reduced the absorption of Cu to 32.1 mg kg−1 and that of Mn to 171.9 mg kg−1. Encapsulation resulted in a significant increase in bacterial survival. This highlights the benefits of using encapsulated microbial consortia from extreme environments, stimulating the growth of C. quinoa, especially in soils with metal(loid) levels that can be a serious constraint for plant growth.
https://doi.org/10.3390/microorganisms12102066