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 (WOS. Impact Factor 6.7 Q1).






Genome Sequence of Brevundimonas sp., an Arsenic Resistant Soil Bacterium

Author Full Names: Soto, Javiera; Charles, Trevor C.; Lynch, Michael D. J.; Larama, Giovanni; Herrera, Hector; Arriagada, Cesar


Brevundimonas sp. is a bacteria able to grow in metal(loid) contaminated soil from Puchuncavi Valley, central Chile. This study has isolated a bacterial strain capable of growth under high doses of arsenic (As) (6000 mg L-1), and a draft genome sequence was generated. Additionally, real-time PCR was performed to examine the effect of As on some genes related to As resistance. Results demonstrated a total of 3275 predicted annotated genes with several genes related to the ars operon, metal(loid) resistance-related genes, metal efflux pumps, and detoxifying enzymes. Real-time PCR showed that the arsB involved in the efflux of As was down-regulated, whereas arsR, arsH, and ACR3 did not show differences with the addition of As. Our study provides novel evidence of diverse As regulating systems in tolerant bacteria that will lead to a better understanding of how microorganisms overcome toxic elements and colonize As contaminated soils and to the possible use of their specific properties in bioremediation.

DOI: 10.3390/d13080344

UT (Unique WOS ID): WOS:000688989600001

Cell Wall Calcium and Hemicellulose Have a Role in the Fruit Firmness during Storage of Blueberry (Vaccinium spp.)

Author Full Names: Olmedo, Patricio; Zepeda, Baltasar; Rojas, Barbara; Silva-Sanzana, Christian; Delgado-Rioseco, Joaquin; Fernandez, Kamila; Balic, Ivan; Arriagada, Cesar; Moreno, Adrian A.; Defilippi, Bruno G.; Campos-Vargas, Reinaldo

Source Title: PLANTS-BASEL

The firmness of blueberry is one of its most significant quality attributes. Modifications in the composition of the cell wall have been associated with changes in the fruit firmness. In this work, cell wall components and calcium concentration in two blueberry cultivars with contrasting firmness phenotypes were evaluated at harvest and 30 days cold storage (0 degrees C). High performance anion-exchange chromatography with pulse amperometric detector (HPAEC-PAD) analysis was performed using the Emerald (firmer) and Jewel (softer) blueberry cultivars, showing increased glucose in the firmer cultivar after cold storage. Moreover, the LM15 antibody, which recognizes xyloglucan domains, displayed an increased signal in the Emerald cultivar after 30 d cold storage. Additionally, the antibody 2F4, recognizing a homogalacturonan calcium-binding domain, showed a greater signal in the firmer Emerald blueberries, which correlates with a higher calcium concentration in the cell wall. These findings suggest that xyloglucan metabolism and a higher concentration of cell wall calcium influenced the firmness of the blueberry fruit. These results open new perspectives regarding the role of cell wall components as xyloglucans and calcium in blueberry firmness.


UT (Unique WOS ID): WOS:000634059500001

Soil contamination with phenanthrene induces maize mycorrhiza growth suppression

Author Full Names: Lagos, Claudio A.; Diaz, Tsiri; Saucedo, Estefania; Arriagada, Cesar; Larsen, John; Jaramillo-Lopez, Pablo F.


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

Inoculation of Triticum Aestivum L. (Poaceae) with Plant-Growth-Promoting Fungi Alleviates Plant Oxidative Stress and Enhances Phenanthrene Dissipation in Soil

Author Full Names: Lagos, Claudio; Larsen, John; Fuentes, Alejandra; Herrera, Hector; Garcia-Romera, Inmaculada; Campos-Vargas, Reinaldo; Arriagada, Cesar


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

Effect of arbuscular mycorrhizal fungi and mycoremediated dry olive residue in lead uptake in wheat plants

Author Full Names: Garcia-Sanchez, Mercedes; Andrea Silva-Castro, Gloria; Sanchez, Alvaro; Arriagada, Cesar; Garcia-Romera, Inmaculada


This study aims to evaluate the role of the extraradical mycelium of arbuscular mycorrhizal fungi in Pb transport. We also investigate how these fungi, alone or combined with the mycoremediated dry olive residue (MDOR), provide protection against Pb. We established a container system consisting of a central compartment and two lateral compartments separated by a hydrophobic membrane. The central compartment was filled with sterilized soil in which wheat plants, inoculated and non-inoculated with Funneliformis mosseae, were grown. The lateral compartments were filled with sterile, Pb-contaminated or MDOR-amended soil or combinations of both. In contrast to shoots and grains, wheat roots accumulated larger amounts of Pb with or without applications of MDOR. The extraradical mycelium (ERM) and the glomalin related protein content were significantly boosted by adding MDOR to Pb-contaminated soil samples. Wheat mot biomass was decreased as the result of Pb contamination with no increases in plant phosphorous (P) uptake. However, MDOR, when added to Pbcontaminated soil samples, only boosted the accumulation of P in roots, with P content and biomass remaining unchanged in wheat shoots and grains. Our study highlights the role of the ERM in Pb transport its accumulation in wheat mots and how the protection effect exerted by AMF seemed to rely on MDOR application by increasing the P uptake rather than Pb.

DOI: 10.1016/j.apsoil.2020.103838

UT (Unique WOS ID): WOS:000609456600020

Controlled mycorrhization of the endemic Chilean orchidChloraea gavilu(Orchidaceae)

Author Full Names: Pereira, Guillermo; Herrera, Hector; Arriagada, Cesar; Cid, Hertes; Garcia, Jose Leonardo; Atala, Cristian


Orchids require mycorrhizal fungi (OMF) for their germination and growth. Propagation and re-introduction initiatives would likely require inoculation with such fungi. All Chilean Orchidaceae species are terrestrial and likely associate with OMF. We collected adult individuals of the endemic Chilean orchidChloraea gaviluand transported them to a glasshouse where we obtained mature capsules through manual auto-pollination. We asymbiotically germinated seeds in vitro using Malmgren Modified Terrestrial Orchid-Medium (MM). Embryos were put in glass flasks with MM where roots and leaves developed for 16 weeks. Plants were then transplanted to 165 mL pots and randomly separated into three groups; plants inoculated separately withCeratobasidiumOMFs isolated from two Chilean orchid species (Chloraea virescensandCodonorchis lessonii), and uninoculated (control) plants. Plants were then put in a growth chamber. Three months later, inoculated individuals showed pelotons inside parenchyma cells in the roots. Four months after inoculation, mycorrhizal plants had higher root and shoot biomass compared to control plants. At the end of the experiment, the highest mycorrhization was achieved with theCeratobasidiumstrain isolated fromC. lessonii. The artificial mycorrhization of endemic orchids could be a key strategy for future conservation and propagation initiatives, especially for endangered or commercially interesting species.

DOI: 10.1080/11263504.2020.1801875

UT (Unique WOS ID): WOS:000562194000001