Gustavo Zuñiga

University of Santiago, Chile | USACH · Departamento de Biología

This study investigates the antifungal efficacy of flavonoids derived from Colobanthus quitensis against key virulence‐related enzymes implicated in the pathogenic mechanisms of Botrytis cinerea. The flavonoids swertiajaponin, schaftoside, vitexin, and saponarin significantly inhibited pectinase, cellulase, and laccase activity. Specifically, swert...

KEYWORDS plant, extreme environment, astrobiology, deep space exploration, limits of life Editorial on the Research Topic Revisiting the limits of plant life-plant adaptations to extreme terrestrial environments relating to astrobiology and space biology Plants were essential to the early evolution of terrestrial life and colonization of the young...

Laccases are industrially relevant enzymes that are known for the wide variety of substrates they can use. In recent years, fungal laccases have been progressively replaced by bacterial laccases in applied contexts due to their capacity to work on harsh conditions including high temperatures, pHs, and chloride concentrations. The focus of researche...

Aristotelia chilensis is a plant whose fruit is considered a powerful natural antioxidant. During the last years, some investigations of the fruit have been carried out, finding antioxidant properties in the juice or the phenolic fraction. The antioxidant properties of the plant are useful in the inhibition of enzymes related to diabetes such as pa...

This study sought to evaluate the pharmacological activity of metabolites isolated from the dried and lyophilized ethanol extracts as well as other solvent fractions of the currently endangered Puya chilensis Molina (Chagual) by analyzing their effects on a human hepatocellular carcinoma (HCC) cell line. We identified several active metabolites fro...

Botrytis cinerea, a responsible for grey rot that mainly affects fruit and represent a problem in fruit-exporting countries. synthetic antifungals are used for its control. however, it has developed a specific resistance towards them. therefore, a search for new natural alternatives that are friendly to the environment has increased in the last dec...

In this work, we have investigated the accumulation of ryanoids in different plant parts (leaves, stems and roots) of aeroponically grown Persea indica cloned trees (one-year-old cloned individuals) and a selected mature, wild tree. We tested the insect antifeedant (against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and nematicid...

Symbiotic associations with microbes can contribute to mitigating abiotic environmental stress in plants. In this study, we investigated individual and interactive effects of two root endophytic fungal species on physiological and biochemical mechanisms of the crop Chenopodium quinoa in response to salinity. Fungal endophytes (FE) Talaromyces minio...

In this work we have investigated the accumulation of ryanoids in different plant parts (leaves, stems roots) of aeroponically grown Persea indica cloned trees (one year old cloned individuals) and a selected mature wild tree. We have tested the insect antifeedant (against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi) and nematicida...

Deschampsia antarctica Desv, is the most successful colonizing species of a cold continent. In recent years due to climate change, the frequency of heat waves has increased in Antarctica, registering anomalous high temperatures during the summer of 2020. However, the populations of D. antarctica are responding positively to these events, increasing...

The terrestrial flora of Antarctica’s frozen continent is restricted to sparse ice-free areas and dominated by lichens and bryophytes. These plants frequently battle sub-zero temperatures, extreme winds and reduced water availability; all influencing their ability to survive and grow. Antarctic mosses, however, can have canopy temperatures well abo...

There is a growing interest in the use of adsorbent nanoparticles to mitigate the toxic effects of pollutants in natural matrices. However, due to their small size, nanoparticles have the potential to transport and disseminate contaminants adsorbed on their surfaces into environmental compartments with greater risk to human, animal, or plant health...

Xanthophyllomyces dendrorhous synthesizes astaxanthin, a carotenoid used in aquaculture. Astaxanthin is synthesized from metabolites of the mevalonate pathway, which are also precursors for sterols biosynthesis. The interruption of the CYP61 gene, which is involved in the synthesis of ergosterol (mutant CBS.cyp61–), resulted in a phenotype that ove...

This summer, a heatwave across Antarctica saw temperatures soar above average. Temperatures above zero are especially significant because they accelerate ice melt. Casey Station had its highest temperature ever, reaching a maximum of 9.2°C and minimum of 2.5°C. The highest temperature in Antarctica was 20.75°C on 9 February. Here we discuss the bio...

Background: One of the most extreme environments on our planet is the Maritime Antarctic territory, due to its low-water availability, which restricts the development of plants. Sanionia uncinata Hedw. (Amblystegiaceae), the main colonizer of the Maritime Antarctic, has effective mechanisms to tolerate this environment. It has been described that...

Background It has been previously shown that oligo-carrageenan (OC) kappa increases growth, photosynthesis and activities of enzymes involved in basal and secondary metabolisms in Eucalyptus globulus. However, it is not known whether OC kappa may induce the activation of TOR pathway and the increase in expression of genes encoding proteins involved...

Background: With 29 Km2, the Fildes Peninsula is the largest ice free area in King George Island and probably in Antarctica. The region is house of six permanent bases including the only airport in the South Shetlands, which led to impacts on its original landscape and vegetation. In recognition for the need to protect natural values, an Antarctic...

Background In field, C. quitensis is subjected to many abiotic extreme environmental conditions, such as low temperatures, high UV-B, salinity and reduced water potentials, but not metal or metalloid high concentrations in soil, however, other members of Caryophyllaceae family have tolerance to high concentrations of metals, this is the case of Sil...

Colobanthus quitensis, the only dicot that inhabits Antarctica, is subjected to different abiotic factors such as high UV-B levels in spring-summer. Several authors described the flavonoid biosynthesis as crucial to tolerating UV-B enriched environments. The goal of this work is the study of the relationship between biosynthesis of flavonoids, resi...

The role of flavonoids in plant-environmental stress has many biotechnological applications, in this way Antarctic plants have an important potential for molecular farming. However, the concentration and exploitation of resource are highly restricted, for this reason the use of enzymatic machinery of the Antarctic plants have importance for in vitr...

Highlight GMMT (a possible CSLA9 ) from Aloe vera is upregulated during water stress. Aloe vera GMMT expression is also induced by exogenous application of the plant stress hormone abscisic acid (ABA) in non-water-stressed plants. Summary In Aloe barbadensis Miller (Aloe vera), a xerophytic crassulacean acid metabolism (CAM) plant, the main polysa...

Oligo-carrageenan (OC) kappa increases net photosynthesis, and basal and secondary metabolism enzyme activities in Eucalyptus globulus trees. Here, trees were sprayed on leaves with water (control) or with OC kappa 1 mg ml ⁻¹ , once a week, four times in total, and cultivated for 17 additional weeks (21 weeks in total). Height, level of glucose, tr...

To evaluate the potential role of phenolic compounds in Al and Cd stress tolerance mechanisms, Vaccinium corymbosum cv. Legacy plantlets were exposed to different metal concentrations. The present study used an in vitro plant model to test the effects of the following treatments: 100μM Al; 100μMAl + 50μMCd; and 100μMAl + 100μMCd during periods of 7...

Central chemoreception is essential for adjusting breathing to physiological demands, and for maintaining CO 2 and pH homeostasis in the brain. CO 2-induced ATP release from brainstem astrocytes stimulates breathing. NMDA receptor (NMDAR) antagonism reduces the CO 2-induced hyperventilation by unknown mechanisms. Here we show that astrocytes in the...

Aristotelia chilensis (Mol.) Stuntz, commonly called Maqui, is known for its pharmacological uses in traditional medicine of native Mapuche communities in Chile. It is reported to have excellent medicinal properties that help to cure chronic diarrhea, dysentery, throat diseases, intestinal tumors, fever, wounds healing, and scars. Pharmacologically...

Deschampsia antarctica Desv. is one of two vascular plants that live in the Maritime Antarctic Territory and is exposed to high levels of ultraviolet-B (UVB) radiation. In this work, antioxidant physiology of D. antarctica was studied in response to UVB induced oxidative changes. Samples were collected from Antarctica and maintained in vitro cultur...

Fungal pathogens are the cause of the most common diseases in grapevine and among them powdery mildew represents a major focus for disease management. Different strategies for introgression of resistance in grapevine are currently undertaken in breeding programs. For example, introgression of several resistance genes (R) from different sources for...

Background: Cryptogamic vegetation dominates the ice-free areas along the Antarctic Peninsula. The two mosses Sanionia uncinata and Polytrichastrum alpinum inhabit soils with contrasting water availability. Sanionia uncinata grows in soil with continuous water supply, while P. alpinum grows in sandy, non-flooded soils. Desiccation and rehydration...

The aim of this study was to improve the antifungal activity against Botrytis cinerea of syringic acid by using the enzyme laccase to synthesize a heterodimeric compound by a coupling reaction with aniline. The synthesized heterodimer is a quinone-imine like compound (2,6-dimethoxy-4-(phenylimino)benzenone), which was characterized by using ¹H and...

Nine eremophilane sesquiterpenes 1-9, two flavonoids 11 and 12, and two known pirrolizidine alkaloids 13 and 14, were isolated from Senecio adenotrichius DC. Their structures were elucidated on the basis of spectroscopic data and by comparison with previously reported spectroscopic data of similar compounds. Compounds 5, 7 and 9 have not been previ...

Many ecological questions require information on species' optimal conditions or critical limits along environmental gradients. These attributes can be compared to answer questions on niche partitioning, species coexistence and niche conservatism. However, these comparisons are unconvincing when existing methods do not quantify the uncertainty in th...

White Chilean strawberries (Fragaria chiloensis) are non-climacteric fruits, with an exotic color and aroma. In order to discover genes involved in the development of these fruits, we identified a fragment of a gene encoding a late embryogenesis abundant domain protein, FcLDP1, that was expressed in early stages of fruit development, particularly i...

The present invention refers to a photo-thermal bioreactor and method for culture and in vitro micropropagation of Deschampsia antarctica that consists of a discontinuous immersion reactor for biomass micropropagation comprising means to incorporate chemical inducing agents (salt, metals, organic compounds, etc.) and lighting or luminescence means...

The present invention refers to a photo-thermal bioreactor and method for culture and in vitro micropropagation of Deschampsia antarctica that consists of a discontinuous immersion reactor for biomass micropropagation comprising means to incorporate chemical inducing agents (salt, metals, organic compounds, etc.) and lighting or luminescence means...

Berry fruit consumption has become important in the promotion of human health, mainly due to their phenolic compounds, which have been associated with protection against different pathologies, as well as antimicrobial and other biological activities. Consequently, there has been a growing interest in identifying natural antioxidants and antimicrobi...

Cryptogamic vegetation dominates the ice-free areas of the maritime Antarctic. This particular flora grows slowly due to extreme environmental conditions, typically low temperature that may limit growth during a short summer. Over the last 50 years, the Antarctic Peninsula has undergone the highest registered temperature increases in Antarctica. As...

Broccoli sprouts are a good source of secondary metabolites exhibiting biological activity, such as polyphenols, whose concentration is affected by the exposure to exogenous elicitors. The aim of this work was to investigate the effect of sodium selenate, chitosan and methyl-jasmonate, applied directly to the seeds or through irrigation, on the con...

Eucalyptus globulus trees treated with oligo-carrageenan (OC) kappa showed an increase in NADPH, ascorbate and glutathione levels and activation of the thioredoxin reductase (TRR)/thioredoxin (TRX) system which enhance photosynthesis, basal metabolism and growth. In order to analyze whether the reducing redox status and the activation of thioredoxi...

Blueberry is a popular natural food product consumed worldwide. Acid soils are found throughout the world. A significant problem of acid soils is the active aluminum content, which may result toxic to plant. The present study was undertaken to assess the toxicities of Al for Blueberry (Vaccinium corymbosum L.) cultivated in vitro and treated with 1...

Deschampsia antarctica (Poaceae) is one of the two vascular plants known to have colonized the Antarctic region. Studies examining the biosynthesis of flavonoids, compounds which plants use, for example, for protection against overexposure to UV light or as antioxidants that scavenge free radicals and other oxidative species, in D. antarctica may p...

The Pre-Andean area of Chile exhibits saline soils of volcanic origin naturally contaminated with arsenic (As), and we hypothesise that revegetation with resistant species may be a valid alternative for soil management in this area. Thus, the xerophytic and halophytic shrubs Atriplex halimus and Atriplex atacamensis were cultivated in containers fo...

Pathogenic fungi constitute one of the main infectious agents in plants, causing alterations during developmental stages including post-harvest. Phytopathogenic fungi are controlled by synthetic fungicides; however, the use of these is progressively restricted due to both, the harmful effects of pesticides on the environment and human health and th...

The effect of γ‐irradiation on the quality of chives was evaluated. The samples were irradiated at 1.0 and 2.0 kGy, stored at 4 °C for 10 days and used for microbiological (aerobic mesophilic, moulds and yeasts, E. coli and Salmonella sp), biochemical (vitamin C and lipoperoxide (MDA) contents and superoxide dismutase (SOD) and guaiacol peroxidase...

Background Ecotypes of Colobanthus quitensis Kunt Bartl (Cariophyllaceae) from Andes Mountains and Maritime Antarctic grow under contrasting photoinhibitory conditions, reaching differential cold tolerance upon cold acclimation. Photoinhibition depends on the extent of photodamage and recovery capability. We propose that cold acclimation increases...

Deschampsia antarctica (DA), the only species in the Gramineae family endemic to the Antarctic territory, is characterized by a combination of high levels of free endogenous phenylpropanoid compounds under normal in situ and in vitro growth conditions. In this article, we describe the design and use of a specific temporary immersion photobioreactor...

Table grape (Vitis vinifera L.) quality includes the condition of both the berries and the rachis. In the present report, physiological parameters of Red Globe rachises from fully elongated inflorescences (RFEI) and from mature clusters were studied after storage at 0 or 20 °C for different durations. To understand changes in rachis physiology as a...

Las algas marinas son una fuente importante de compuestos antioxidantes (fenoles y polifenoles), generados como mecanismos de defensa frente a factores de estrés (radiación UV, temperatura, herbívora). El objetivo de este trabajo es evaluar la estrategia de adaptación al efecto de la radiación ultravioleta B (RUV-B, 280-315 nm) en la microalga mari...

Marine algae are an important source of antioxidant compounds (phenols and polyphenols), generated as defense mechanisms against stress factors (UV radiation, temperature, herbivory). The aim of this study was to evaluate the strategy of adaptation to the effect of ultraviolet B radiation (UV-B, 280-315 nm) in the marine microalga Chlorella sp. thr...

Deschampsia antarctica (DA) is a prominent vascular plant present in the Antarctic territory which has been able to tolerate extreme conditions for many years. In vitro experiments showed that DA efficiently responds to high salinity conditions (i.e. 300 mM NaCl), modulating gene expression and metabolites content involved in the phenylpropanoid pa...

R. Campos-Vargas, P. Zamora, R. Contreras, H. Kohler, G.E. Zuniga, A. Perez-Donoso, and B.G. Defilippi. 2012. Cold storage effects on oxidative stress of Red Globe table grape rachises. Cien. Inv. Agr. 39(1): 91-104. Table grape (Vitis vinifera L.) quality includes the condition of both the berries and the rachis. In the present report, physiologic...

In order to study the antiviral effect of the oligo-sulphated galactan Poly-Ga, the leaves of tobacco plants Xhanti(NN) were sprayed with water (control), with increasing concentrations of Poly-Ga, for increasing numbers of treatments or cultivated for increasing times after treatment. Control and treated plants were infected with tobacco mosaic vi...

Gramine (N,N-Dimethyl-3-aminomethylindole) content in various barley cultivars varied from 0 to 2.6 mmoles/kg fresh weight. Those cultivars which were lacking gramine were the most susceptible to the aphid Rhopalosiphum padi (L.). The population growth rate of R. padi negatively correlated with gramine content in leaves of barley seedlings. In addi...

A study was conducted in the greenhouse to determine the effects of conventional and organic nitrogen (N) fertilizer on Fusarium wilt, caused by Fusarium solani, in northern highbush blueberry (Vaccinium corymbosum L. ‘Legacy’). Root colonization by mycorrhizal fungi, soil microbial activity, and leaf antioxidants content was also measured the trea...

To understand the adaptability to environmental stresses by Deschampsia antarctica, one of the two vascular plants growing in Antarctica, we analysed the activity of several antioxidant enzymes, including peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6)) and glutathion reductase (GR, EC 1.6.4.2),...

Primary photochemistry of photosystem II (F v/F m) of the Antarctic hair grass Deschampsia antarctica growing in the field (Robert Island, Maritime Antarctic) and in the laboratory was studied. Laboratory plants were grown at a photosynthetic photon flux density (PPFD) of 180 μmol m−2 s−1 and an optimal temperature (13 ± 1.5°C) for net photosynthes...

We evaluated the genotype and maturity effects on antioxidant activity and phenolic compounds of whole, skin and pulp fruits from three highbush blueberry cultivare (cv. Brigitta, cv. Bluegold and cv. Legacy) grown in southern Chile. Total antioxidant activity (TAA) in ripe fruits varied among the cultivare in the order Legacy > Brigitta > Bluegold...

The Antarctic Pearlwort, Colobanthus quitensis (Kunth.) Bartl. (Caryophyllaceae) is one of the two native vascular plant species that have successfully colonized the maritime Antarctic during the Holocene (Smith 1984). Within the Antarctic biome, it is only found on the Antarctic Peninsula and on islands in the maritime Antarctic (Smith 1984). Its...