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Antarctica has one of the most sensitive ecosystems to the negative effects of Persistent Organic Pollutants (POPs) on its biodiversity. This is because of the lower temperatures and the persistence of POPs that promote their accumulation or even biomagnification. However, the impact of POPs on vascular plants is unknown. Moreover, fungal symbionts could modulate the effects on host plants to cope with this stress factor. This study investigates the molecular and ecophysiological responses of the Sub-Antarctic and Antarctic plant Colobanthus quitensis to POPs in different populations along a latitudinal gradient (53°- 67° S), emphasizing the role of endophytic fungi. The results show that exposure of POPs in C. quitensis generates oxidative stress and alters its ecophysiological performance. Nevertheless, C. quitensis in association with fungal endophytes and POPs exposure, shows lower lipid peroxidation, higher proline content and higher photosynthetic capacity, as well as higher biomass and survival percentage, compared to plants in the absence of fungal endophytes. On the other hand, the antarctic plant population (67°S) with endophytic fungi presents better stress modulating upon POPs exposure. Endophytic fungi would be more necessary for plant performance towards higher latitudes with extreme conditions, contributing significantly to their general functional adaptation. We develop a transcriptomics analyses n the C. quitensis-fungal endophytes association from the Peninsula population. We observed that fungal endophytes promote tolerance to POPs stress through upregulated genes for the redox regulation based on ascorbate and scavenging mechanisms (peroxidases, MDAR, VTC4, CCS), transformation (monooxygenases) and conjugation of compounds or metabolites (glutathione transferases, glycosyltransferases, S-transferases), and the storage or elimination of conjugates (ABC transporters, C and G family) that contribute to detoxification cell. This work highlights the contribution of endophytic fungi to plant resistance in situations of environmental stress, especially in extreme conditions such as in antarctica exposed to anthropogenic impact. The implications of these findings are relevant for the biosecurity of one of the last pristine bastions worldwide., (© 2025 Scandinavian Plant Physiology Society.)

Despite their genetic adaptation to local conditions, plants often achieve ecological success through symbiotic associations with fungal endophytes. However, the habitat-specific functionality of these interactions and their potential to drive plant adaptation to new environments remain uncertain. In this study, we tested this using the vascular flora of the Antarctic tundra (Colobanthus quitensis and Deschampsia antarctica), an extreme environment where fungal endophytes are known for playing important ecological roles. After characterizing the root-associated fungal endophyte communities of both species in two distinct Antarctic terrestrial habitats-hill and coast-we experimentally assessed the contribution of fungal endophytes to plant adaptation in each habitat. The field reciprocal transplant experiment involved removing endophytes from a set of plants and crossing symbiotic status (with and without endophytes) with habitat for both species, aiming to assess plant performance and fitness. The diversity of root fungal endophytes was similar between habitats and mainly explained by plant species, although habitat-specific endophyte community structures were identified in D. antarctica. Endophytes significantly influenced C. quitensis homeostatic regulation, including oxidative stress and osmotic control, as well as plant fitness in both environments. By contrast, the effect of endophytes on D. antarctica was particularly evident in coastal sites, suggesting an endophyte-mediated improvement in local adaptation. Altogether, our results suggest that the two Antarctic vascular plant species follow different strategies in recruiting and developing functional symbiosis with root-associated fungal communities. While C. quitensis is more generalist, D. antarctica establishes specific interactions with habitat-specific microbial symbionts, predominantly in the most stressful environmental context., (© 2024 Scandinavian Plant Physiology Society.)

Ground-level ozone is a global air pollutant with high toxicity and represents a threat to plants and microorganisms. Although beneficial microorganisms can improve host performance, their role in connecting environmentally induced maternal plant phenotypes to progeny (transgenerational effects [TGE]) is unknown. We evaluated fungal endophyte-mediated consequences of maternal plant exposure to ozone on performance of the progeny under contrasting scenarios of the same factor (high and low) at two stages: seedling and young plant. With no variation in biomass, maternal ozone-induced oxidative damage in the progeny that was lower in endophyte-symbiotic plants. This correlated with an endophyte-mediated higher concentration of proline, a defence compound associated with stress control. Interestingly, ozone-induced TGE was not associated with reductions in plant survival. On the contrary, there was an overall positive effect on seedling survival in the presence of endophytes. The positive effect of maternal ozone increasing young plant survival was irrespective of symbiosis and only expressed under high ozone condition. Our study shows that hereditary microorganisms can modulate the capacity of plants to transgenerationally adjust progeny phenotype to atmospheric change., (© 2021 John Wiley & Sons Ltd.)

Climatic change is pointed as one of the major challenges for global food security. Based on current models of climate change, reduction in precipitations and in turn, increase in the soil salinity will be a sharp constraint for crops productivity worldwide. In this context, root fungi appear as a new strategy to improve plant ecophysiological performance and crop yield under abiotic stress. In this study, we evaluated the impact of the two fungal endophytes Penicillium brevicompactum and P. chrysogenum isolated from Antarctic plants on nutrients and Na + contents, net photosynthesis, water use efficiency, yield and survival in tomato and lettuce, facing salinity stress conditions. Inoculation of plant roots with fungal endophytes resulted in greater fresh and dry biomass production, and an enhanced survival rate under salt conditions. Inoculation of plants with the fungal endophytes was related with a higher up/down-regulation of ion homeostasis by enhanced expression of the NHX1 gene. The two endophytes diminished the effects of salt stress in tomato and lettuce, provoked a higher efficiency in photosynthetic energy production and an improved sequestration of Na + in vacuoles is suggested by the upregulating of the expression of vacuolar NHX1 Na + /H + antiporters. Promoting plant-beneficial interactions with root symbionts appears to be an environmentally friendly strategy to mitigate the impact of climate change variables on crop production.

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09' S), and Lagotellerie Island in the Antarctic Peninsula (65°53' S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Technological advances have made possible long space travels and even exoplanetary colonies in the future. Nevertheless, the success of these activities depends on our ability to produce edible plants in stressful conditions such as high radiation, extreme temperatures and low oxygen levels. Since beneficial microorganisms, such as fungal endophytes from extreme environments, have helped agriculture cope with those difficulties, endophytic fungi may be a putative tool to ensure plant growth under exoplanetary conditions. Additionally, growing crops in polyculture has been shown to increase productivity and spatial efficiency, which is essential given the likely space restrictions in such conditions. Methods: We evaluated the effect of the inoculation with a mix of two fungal endophytes from the Atacama Desert on performance (survival and biomass) and nutritional quality of three crop species (lettuce, chard and spinach) grown under exoplanetary conditions. In addition, we measured the amount of antioxidants (flavonoids and phenolics) as possible mechanisms to cope with such abiotic conditions. The exoplanetary conditions were; high UV radiation, low temperature, low water availability, and low oxygen levels. These crops were put in growing chambers in monoculture, dual culture and polyculture (the three species in the same pot) for 30 days. Results and Discussion: Our results show that inoculation with extreme endophytes improved survival by ca. 15 - 35% and biomass by ca. 30 - 35% in all crop species. The most evident increase was when grown in polyculture, except for survival in spinach, where inoculated plants had higher survival only in dual culture. Nutritional quality and the amount of the antioxidant compounds antioxidants increased in all crop species when inoculated with the endophytes. Overall, fungal endophytes isolated from extreme environments such as the Atacama Desert, the driest desert in the world, could be a key biotechnological tool for future space agriculture, helping plants cope with environmental stress. Additionally, inoculated plants should be grown in polyculture to increase crop turnover and space-use efficiency. Lastly, these results provide useful insights to face the future challenges of space-farming. [ABSTRACT FROM AUTHOR]

Invasive plants may displace native species. This is the case for Poa annua, the only non-native plant species successfully established in Maritime Antarctica. Nonetheless, it is uncertain which factors drive the competitive success of P. annua in the harsh environmental conditions of the region. The ability of this plant species to establish novel mutualistic interactions with resident soil fungi may be crucial for its invasiveness. Such ability may be linked to the vertical transmission of fungal endophytes via seeds. We undertook a study to assess the role of seed fungal endophytes as promoters of the establishment and invasion of Poa annua in Maritime Antarctica. We explored the composition and diversity of fungal communities associated with different P. annua tissues (seeds, leaves and roots) and the soil. We also measured parameters including germination rate, above-ground biomass, reproductive structures, and the survival of invasive P. annua as well as of the native Colobanthus quitensis and Deschampsia antarctica grown from seeds with and without endophytes. Furthermore, we conducted inter- and intraspecific competition experiments among native and invasive plants, where chemically mediated plant-to-plant interference (allelopathy) and plant growth rate were measured to calculate a relative competition index. We found that fungal endophyte taxa associated with P. annua tissues were very different from those in the soil. Fungal endophytes in P. annua differed among seed, root and shoot tissues, which suggests low transmission among different organs. The removal of endophytes from P. annua seeds was associated with reduced seed germination, plant growth and survivorship, while the competitive ability of P. annua (assessed by accumulated biomass) relative to native species, as well as levels of allelochemicals in soils, were higher in the presence of seed fungal endophytes. Our results suggest that fungal endophytes, maternally inherited through seeds, improve host fitness and may contribute to the invasive success of P. annua in Antarctica. [ABSTRACT FROM AUTHOR]

Plant-fungi interactions have been identified as fundamental drivers of the plant host performance, particularly in cold environments where organic matter degradation rates are slow, precisely for the capacity of the fungal symbiont to enhance the availability of labile nitrogen (N) in the plant rhizosphere. Nevertheless, these positive effects appear to be modulated by the composition and amount of the N pool in the soil, being greater when plant hosts are growing where N is scarce as is the case of Antarctic soils. Nevertheless, in some coastal areas of this continent, seabirds and marine mammal colonies exert, through their accumulated feces and urine a strong influence on the edaphic N content surrounding their aggregation points. To evaluate if the fungal symbionts (root endophytes), associated to the only two Antarctic vascular plants Colobanthus quitensis and Deschampsia antarctica , act as N-uptake enhancers, even in such N-rich conditions as those found around animal influence, we assessed, under controlled conditions, the process of N mineralization in soil by the accumulation of NH4+ in the rizhosphere and the biomass accumulation of plants with (E+) and without (E−) fungal symbionts. Complementarily, taking advantage of the isotopic N-fractionation that root-fungal symbionts exert on organic N molecules during its acquisition process, we also determined if endophytes actively participate in the Antarctic plants N-uptake, when inorganic N is not a limiting factor, by estimating the δ15N isotopic signatures in leaves. Overall, symbiotic interaction increased the availability of NH4+ in the rhizosphere of both species. As expected, the enhanced availability of inorganic N resulted in a higher final biomass in E + compared with E− plants of both species. In addition, we found that the positive role of fungal symbionts was also actively linked to the process of N-uptake in both species, evidenced by the contrasting δ15N signatures present in E+ (−0.4 to −2.3‰) relative to E− plants (2.7–3.1‰). In conclusion, despite being grown under rich N soils, the two Antarctic vascular plants showed that the presence of root-fungal endophytes, furthermore enhanced the availability of inorganic N sources in the rhizosphere, has a positive impact in their biomass, remarking the active participation of these endophytes in the N-uptake process for plants inhabiting the Antarctic continent. [ABSTRACT FROM AUTHOR]

In this review, we examine the functional roles of microbial symbionts in plant tolerance to cold and freezing stresses. The impacts of symbionts on antioxidant activity, hormonal signaling and host osmotic balance are described, including the effects of the bacterial endosymbionts Burkholderia, Pseudomonas and Azospirillum on photosynthesis and the accumulation of carbohydrates such as trehalose and raffinose that improve cell osmotic regulation and plasma membrane integrity. The influence of root fungal endophytes and arbuscular mycorrhizal fungi on plant physiology at low temperatures, for example their effects on nutrient acquisition and the accumulation of indole‐3‐acetic acid and antioxidants in tissues, are also reviewed. Meta‐analyses are presented showing that aspects of plant performance (shoot biomass, relative water content, sugar and proline concentrations and Fv/Fm) are enhanced in symbiotic plants at low (−1 to 15 °C), but not at high (20–26 °C), temperatures. We discuss the implications of microbial symbionts for plant performance at low and sub‐zero temperatures in the natural environment and propose future directions for research into the effects of symbionts on the cold and freezing tolerances of plants, concluding that further studies should routinely incorporate symbiotic microbes in their experimental designs. [ABSTRACT FROM AUTHOR]

Climatic change is pointed as one of the major challenges for global food security. Based on current models of climate change, reduction in precipitations and in turn, increase in the soil salinity will be a sharp constraint for crops productivity worldwide. In this context, root fungi appear as a new strategy to improve plant ecophysiological performance and crop yield under abiotic stress. In this study, we evaluated the impact of the two fungal endophytes Penicillium brevicompactum and P. chrysogenum isolated from Antarctic plants on nutrients and Na+ contents, net photosynthesis, water use efficiency, yield and survival in tomato and lettuce, facing salinity stress conditions. Inoculation of plant roots with fungal endophytes resulted in greater fresh and dry biomass production, and an enhanced survival rate under salt conditions. Inoculation of plants with the fungal endophytes was related with a higher up/down-regulation of ion homeostasis by enhanced expression of the NHX1 gene. The two endophytes diminished the effects of salt stress in tomato and lettuce, provoked a higher efficiency in photosynthetic energy production and an improved sequestration of Na+ in vacuoles is suggested by the upregulating of the expression of vacuolar NHX1 Na+/H+ antiporters. Promoting plant-beneficial interactions with root symbionts appears to be an environmentally friendly strategy to mitigate the impact of climate change variables on crop production. [ABSTRACT FROM AUTHOR]

Maritime Antarctica is one of the most stressful environments for plant life worldwide. However, two vascular plant species (Deschampsia antarctica and Colobanthus quitensis) have been able to colonize this hostile environment. Although it has been proposed that C. quitensis possesses tolerance mechanisms and adaptations allowing survival and growth under such stressful conditions, the underlying molecular/transcriptional mechanisms are currently unknown. Furthermore, the impact of global warming on the endophytic and epiphytic organisms associated with C. quitensis remains unclear. Here, a metatranscriptomic approach was used to determine the effect of an in situ simulated global warming scenario on C. quitensis plants. We found a large number of differentially expressed genes successfully annotated (2,997), suggesting that climate change modulates the metatranscriptome of C. quitensis plants and associated endophytes and epiphytes. Interestingly, 50.5% and 26.8% of up- and down-regulated genes, respectively, are from non-plant species (putative endophytic and epiphytic organisms, such as fungi). Interestingly, Gene Ontology analysis pointed out several biological processes differentially enriched in non-plant microorganisms associated with C. quitensis grown in a simulated global warming scenario. Taken together, these results suggest that climatic drivers are shaping plant-microorganism interactions, and that endophytes/epiphytes may play crucial roles in plant adaptation to extreme environmental conditions. [ABSTRACT FROM AUTHOR]