scholarly journals Root fungal endophytes improve the growth of antarctic plants through an enhanced nitrogen acquisition

2018 ◽  
Author(s):  
Romulo Oses Pedraza ◽  
Cristian Torres-Díaz ◽  
Paris Lavin ◽  
Patricio Retamales-Molina ◽  
Cristian Atala ◽  
...  
Keyword(s):  
Nitrogen Mineralization ◽  
Vascular Plants ◽  
Fungal Endophytes ◽  
Deschampsia Antarctica ◽  
Total Biomass ◽  
Hormone Production ◽  
Single Spore ◽  
Nutrient Sources ◽  
Root Endophytes ◽  
Antarctic Plants

Mutualistic symbiosis with fungal endophytes has been suggested as a possible mechanism for extreme environment colonization by Antarctic vascular plants. Fungal endophytes improve plant stress tolerance and performance by increasing plant hormone production and the uptake of water and nutrients. However, there are still gaps regarding the mechanisms by which these process ocurr. This work explores the role of root fungal endophytes in the production of exolytic enzymes involved in endophyte-mediated mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants. Hence, we evaluated the ability of fungal endophytes isolated from the two native Antarctic vascular plants, Colobanthus quitensis and Deschampsia antarctica, to enzymatically degrade different nutrient sources, mediate nitrogen mineralization and enhance growth of the host plant. Single-spore derived isolates were identified using molecular and morphological approaches. Penicillium chrysosgenum and Penicillium brevicompactum were identified as the dominant root endophytes in C. quitensis and D. antarctica, respectively. Root endophytes exhibited hydrolytic and oxidative enzymatic activities involved in carbohydrate or protein breakdown and phosphorus solubilization. In addition, the rates and porcentages of nitrogen mineralization, as well as the final total biomass were significantly higher in C. quitensis and D. antarctica individuals with root endophytes relative to those without endophytes. Our findings suggest that root endophytes exert a pivotal ecological role based not only on their capability to breakdown different nutrient sources but also accelerating nitrogen mineralization, improving nutrient acquisition and promoting plant growth in limited nutrient soils in Antarctic terrestrial ecosystems

scholarly journals Root fungal endophytes improve the growth of antarctic plants through an enhanced nitrogen acquisition

2018 ◽  
Author(s):  
Romulo Oses Pedraza ◽  
Cristian Torres-Díaz ◽  
Paris Lavin ◽  
Patricio Retamales-Molina ◽  
Cristian Atala ◽  
...  
Keyword(s):  
Nitrogen Mineralization ◽  
Vascular Plants ◽  
Fungal Endophytes ◽  
Deschampsia Antarctica ◽  
Total Biomass ◽  
Hormone Production ◽  
Single Spore ◽  
Nutrient Sources ◽  
Root Endophytes ◽  
Antarctic Plants

Mutualistic symbiosis with fungal endophytes has been suggested as a possible mechanism for extreme environment colonization by Antarctic vascular plants. Fungal endophytes improve plant stress tolerance and performance by increasing plant hormone production and the uptake of water and nutrients. However, there are still gaps regarding the mechanisms by which these process ocurr. This work explores the role of root fungal endophytes in the production of exolytic enzymes involved in endophyte-mediated mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants. Hence, we evaluated the ability of fungal endophytes isolated from the two native Antarctic vascular plants, Colobanthus quitensis and Deschampsia antarctica, to enzymatically degrade different nutrient sources, mediate nitrogen mineralization and enhance growth of the host plant. Single-spore derived isolates were identified using molecular and morphological approaches. Penicillium chrysosgenum and Penicillium brevicompactum were identified as the dominant root endophytes in C. quitensis and D. antarctica, respectively. Root endophytes exhibited hydrolytic and oxidative enzymatic activities involved in carbohydrate or protein breakdown and phosphorus solubilization. In addition, the rates and porcentages of nitrogen mineralization, as well as the final total biomass were significantly higher in C. quitensis and D. antarctica individuals with root endophytes relative to those without endophytes. Our findings suggest that root endophytes exert a pivotal ecological role based not only on their capability to breakdown different nutrient sources but also accelerating nitrogen mineralization, improving nutrient acquisition and promoting plant growth in limited nutrient soils in Antarctic terrestrial ecosystems

scholarly journals Effect of Ionizing Radiation on the Bacterial and Fungal Endophytes of the Halophytic Plant Kalidium schrenkianum

2021 ◽  
Vol 9 (5) ◽  
pp. 1050
Author(s):  
Jing Zhu ◽  
Xiang Sun ◽  
Zhi-Dong Zhang ◽  
Qi-Yong Tang ◽  
Mei-Ying Gu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ionizing Radiation ◽  
Endophytic Bacteria ◽  
Fungal Endophytes ◽  
Root Endophytes ◽  
Fungal Community Structure ◽  
Geochemical Factors ◽  
Bacteria And Fungi ◽  
High Level ◽  
And Control

Endophytic bacteria and fungi colonize plants that grow in various types of terrestrial and aquatic ecosystems. Our study investigates the communities of endophytic bacteria and fungi of halophyte Kalidium schrenkianum growing in stressed habitats with ionizing radiation. The geochemical factors and radiation (at low, medium, high level and control) both affected the structure of endophytic communities. The bacterial class Actinobacteria and the fungal class Dothideomycetes predominated the endophytic communities of K. schrenkianum. Aerial tissues of K. schrenkianum had higher fungal diversity, while roots had higher bacterial diversity. Radiation had no significant effect on the abundance of bacterial classes. Soil pH, total nitrogen, and organic matter showed significant effects on the diversity of root endophytes. Radiation affected bacterial and fungal community structure in roots but not in aerial tissues, and had a strong effect on fungal co-occurrence networks. Overall, the genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments, however negative correlations were found between endophytic bacteria and fungi in the plant. The genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments. Our findings suggest that radiation affects root endophytes, and that the endophytes associated with aerial tissues and roots of K. schrenkianum follow different mechanisms for community assembly and different paradigms in stress response.

scholarly journals Isolation and Characterization of Cold-Tolerant Hyper-ACC-Degrading Bacteria from the Rhizosphere, Endosphere, and Phyllosphere of Antarctic Vascular Plants

2020 ◽  
Vol 8 (11) ◽  
pp. 1788
Author(s):  
Macarena A. Araya ◽  
Tamara Valenzuela ◽  
Nitza G. Inostroza ◽  
Fumito Maruyama ◽  
Milko A. Jorquera ◽  
...  
Keyword(s):  
Abiotic Stresses ◽  
Vascular Plants ◽  
Acc Deaminase ◽  
Deschampsia Antarctica ◽  
Ice Recrystallization Inhibition ◽  
Isolation And Characterization ◽  
Degrading Bacteria ◽  
Recrystallization Inhibition ◽  
Cold Tolerant ◽  
The Antarctic

1-Aminociclopropane-1-carboxylate (ACC)-degrading bacteria having been widely studied for their use in alleviating abiotic stresses in plants. In the present study, we isolated and characterized ACC-degrading bacteria from the rhizosphere, phyllosphere, and endosphere of the Antarctic vascular plants Deschampsia antarctica and Colobanthus quitensis. One hundred and eighty of the 578 isolates (31%) were able to grow on minimal medium containing ACC, with 101 isolates (23, 37, and 41 endosphere-, phyllosphere- and rhizosphere-associated isolates, respectively) identified as being genetically unique by enterobacterial repetitive intergenic consensus (ERIC)-PCR. Subsequently, freeze/thaw treatments and ice-recrystallization-inhibition (IRI) activity assays were performed, the results of which revealed that 77 (13%) of cold-tolerant isolates exhibited putative ACC deaminase activity. Significant (p ≤ 0.05) differences in IRI activity were also observed between the studied plant niches. Surprisingly, all the cold-tolerant isolates showed ACC deaminase activity, independent of the plant niches, with 12 isolates showing the highest ACC deaminase activities of 13.21–39.56 mmol α KB mg protein−1 h−1. These isolates were categorized as ‘cold-tolerant hyper-ACC-degrading bacteria’, and identified as members of Pseudomonas, Serratia, and Staphylococcus genera. The results revealed the occurrence of cold-tolerant hyper-ACC-degrading bacteria in diverse plant niches of Antarctic vascular plants, that could be investigated as novel microbial inoculants to alleviate abiotic stresses in plants.

Accumulation of dehydrin transcripts and proteins in response to abiotic stresses in Deschampsia antarctica

2004 ◽  
Vol 16 (2) ◽  
pp. 175-184 ◽  
Author(s):  
NÉLIDA OLAVE-CONCHA ◽  
SIMÓN RUIZ-LARA ◽  
XIMENA MUÑOZ ◽  
LEÓN A. BRAVO ◽  
LUIS J. CORCUERA
Keyword(s):  
Low Temperature ◽  
Osmotic Stress ◽  
Vascular Plants ◽  
Ice Nucleation ◽  
Northern Analysis ◽  
Deschampsia Antarctica ◽  
Protein Accumulation ◽  
Exogenous Aba ◽  
Epidermal Tissue ◽  
Dehydrin Gene

Deschampsia antarctica Desv. is one of two vascular plants from the Maritime Antarctic. It is usually exposed to cold, salt, and desiccating winds. We hypothesize that D. antarctica has genes that encode dehydrin proteins and their expression is regulated by low temperature, salt or osmotic stress. To test this hypothesis a fragment of a dehydrin gene from D. antarctica was identified and used as a probe to study dehydrin expression under low temperature, salt, and osmotic stress, and exogenous ABA (abscisic acid) treatments. An anti-dehydrin antibody was also used to study dehydrin protein accumulation under the same treatments. Southern analysis of genomic DNA treated with different endonucleases showed more than four bands recognized by the probe, suggesting that D. antarctica has several dehydrin genes. Northern analysis showed two putative dehydrin transcripts of 1.0 kb accumulated only under exogenous ABA and 1.6 kb under osmotic and salt treatments, suggesting that D. antarctica would have ABA-dependent and - independent pathways for regulation of dehydrin expression. Western analysis showed seven dehydrin proteins (58, 57, 55, 53, 48, 30 and 27 kDa) under the different stress treatments. Cold-accumulated dehydrin proteins were immunolocalized, showing that they are associated with vascular and epidermal tissue, which are preferential ice nucleation zones.

scholarly journals Metagenomic exploration of soils microbial communities associated to Antarctic vascular plants

2018 ◽  
Author(s):  
Marco A. Molina-Montenegro ◽  
Gabriel I. Ballesteros ◽  
Eduardo Castro-Nallar ◽  
Claudio Meneses ◽  
Cristian Torres-Díaz ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Vascular Plants ◽  
Plant Performance ◽  
Positive Interactions ◽  
Deschampsia Antarctica ◽  
Rhizospheric Soil ◽  
Biological Impact ◽  
Metagenomic Dna ◽  
Metabolic Functions ◽  
Harsh Conditions

Antarctica is one of the most stressful ecosystems worldwide with few vascular plants, which are limited by abiotic conditions. Here, plants such as Deschampsia antarctica (Da) could generate more suitable micro-environmental conditions for the establishment of other plants as Colobanthus quitensis (Cq). Although, plant-plant interaction is known to determine the plant performance, little is known about how microorganisms might modulate the ability of plants to cope with stressful environmental conditions. Several reports have focused on the possible ecological roles of microorganism with vascular plants, but if the rizospheric microorganisms can modulate the positive interactions among vascular Antarctic plants has been seldom assessed. In this study, we compared the rhizosphere microbiomes associated with Cq, either growing alone or associated with Da, using a shotgun metagenomic DNA sequencing approach and using eggNOG for comparative and functional metagenomics. Overall, results show higher diversity of taxonomic and functional groups in rhizospheric soil from Cq+Da than Cq. On the other hand, functional annotation shows that microorganisms from rhizospheric soil from Cq+Da have a significantly higher representation of genes associated to metabolic functions related with environmental stress tolerance than Cq soils. Additional research is needed to explore both the biological impact of these higher activities in terms of gene transfer on plant performance and in turn help to explain the still unsolved enigma about the strategy deployed by Cq to inhabit and cope with harsh conditions prevailing in Antarctica.

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