2024
Ghaderiardakani, Fatemeh; Ulrich, Johann F.; Barth, Emanuel; Quartino, Maria Liliana; Wichard, Thomas
In: Journal of Plant Growth Regulation, 2024.
Abstract | Links | BibTeX | Tags: algae, bacteria
@article{nokey,
title = {Algal Growth and Morphogenesis-Promoting Factors Released by Cold-Adapted Bacteria Contribute to the Resilience and Morphogenesis of the Seaweed Ulva (Chlorophyta) in Antarctica (Potter Cove)},
author = {Fatemeh Ghaderiardakani and Johann F. Ulrich and Emanuel Barth and Maria Liliana Quartino and Thomas Wichard},
doi = {10.1007/s00344-024-11507-4},
year = {2024},
date = {2024-10-14},
journal = {Journal of Plant Growth Regulation},
abstract = {Macroalgae are found in a variety of marine vegetation ecosystems around the world, contributing significantly to global net primary production. In particular, the sea lettuce species, i.e., members of the genus Ulva (Chlorophyta), are located in many ecological niches and are characterized by excellent adaptability to environmental changes but depend on essential associated bacteria, which release algal growth and morphogenesis-promoting-factors (AGMPFs). Our work investigated the hypothesis that bacteria need to be stress-adapted to provide sufficient amounts of AGMPFs for the growth and morphogenesis of Ulva throughout its life cycle, even under severe environmental conditions. Our study thus aimed to understand which bacteria contribute to overcoming a variety of stressors in polar regions. Green macroalgae were collected from Potter Cove, King George Island (Isla 25 de Mayo), Antarctica, to study the associated microbiome and, subsequently, to identify AGMPFs releasing bacteria. Therefore, microbiome analysis was combined with morphogenetic bioassays and chemical analysis, identifying bacteria essential for algal growth under Antarctic conditions. Hereby, axenic cultures of Ulva compressa (cultivar Ulva mutabilis, Ria Formosa, Portugal), previously developed as a model system for bacteria-induced algal growth and morphogenesis, were inoculated with freshly isolated and cultivable Antarctic bacteria to determine their morphogenetic activity. The exploratory microbiome investigation identified numerous cold-adapted AGMPF-producing bacteria. Unlike the temperate-adapted bacterial strains originally isolated from the U. mutabilis holobiont, the cold-adapted isolates Maribacter sp. BPC-D8 and Sulfitobacter sp. BPC-C4 released sufficient amounts of AGMPFs, such as thallusin and still unknown compounds, necessary for the morphogenesis of the Antarctic Ulva even at 2 °C. Our results illustrate the role of chemical mediators provided by bacteria in cross-kingdom interactions under cold conditions within aquatic systems. The newly isolated bacteria will enable further functional studies to understand the resilience of the holobiont Ulva and might be applied in algal aquaculture even under adverse conditions. The study highlights the importance of eco-physiological assays in microbiome analysis.},
keywords = {algae, bacteria},
pubstate = {published},
tppubtype = {article}
}
Macroalgae are found in a variety of marine vegetation ecosystems around the world, contributing significantly to global net primary production. In particular, the sea lettuce species, i.e., members of the genus Ulva (Chlorophyta), are located in many ecological niches and are characterized by excellent adaptability to environmental changes but depend on essential associated bacteria, which release algal growth and morphogenesis-promoting-factors (AGMPFs). Our work investigated the hypothesis that bacteria need to be stress-adapted to provide sufficient amounts of AGMPFs for the growth and morphogenesis of Ulva throughout its life cycle, even under severe environmental conditions. Our study thus aimed to understand which bacteria contribute to overcoming a variety of stressors in polar regions. Green macroalgae were collected from Potter Cove, King George Island (Isla 25 de Mayo), Antarctica, to study the associated microbiome and, subsequently, to identify AGMPFs releasing bacteria. Therefore, microbiome analysis was combined with morphogenetic bioassays and chemical analysis, identifying bacteria essential for algal growth under Antarctic conditions. Hereby, axenic cultures of Ulva compressa (cultivar Ulva mutabilis, Ria Formosa, Portugal), previously developed as a model system for bacteria-induced algal growth and morphogenesis, were inoculated with freshly isolated and cultivable Antarctic bacteria to determine their morphogenetic activity. The exploratory microbiome investigation identified numerous cold-adapted AGMPF-producing bacteria. Unlike the temperate-adapted bacterial strains originally isolated from the U. mutabilis holobiont, the cold-adapted isolates Maribacter sp. BPC-D8 and Sulfitobacter sp. BPC-C4 released sufficient amounts of AGMPFs, such as thallusin and still unknown compounds, necessary for the morphogenesis of the Antarctic Ulva even at 2 °C. Our results illustrate the role of chemical mediators provided by bacteria in cross-kingdom interactions under cold conditions within aquatic systems. The newly isolated bacteria will enable further functional studies to understand the resilience of the holobiont Ulva and might be applied in algal aquaculture even under adverse conditions. The study highlights the importance of eco-physiological assays in microbiome analysis.
2020
Flores, David Carrasco; Fricke, Markus; Wesp, Valentin; Desirò, Daniel; Kniewasser, Anja; Hölzer, Martin; Marz, Manja; Mittag, Maria
A marine Chlamydomonas sp. emerging as an algal model Journal Article
In: J Phycol, vol. 57, no. 1, pp. 54–69, 2020.
Abstract | Links | BibTeX | Tags: algae, bacteria, DNA / genomics, phylogenetics
@article{Flores:20,
title = {A marine Chlamydomonas sp. emerging as an algal model},
author = {David Carrasco Flores and Markus Fricke and Valentin Wesp and Daniel Desirò and Anja Kniewasser and Martin Hölzer and Manja Marz and Maria Mittag},
doi = {10.1111/jpy.13083},
year = {2020},
date = {2020-10-11},
urldate = {2020-10-11},
journal = {J Phycol},
volume = {57},
number = {1},
pages = {54--69},
publisher = {Wiley},
abstract = {The freshwater microalga Chlamydomonas reinhardtii, which lives in wet soil, has served for decades as a model for numerous biological processes, and many tools have been introduced for this organism. Here, we have established a stable nuclear transformation for its marine counterpart, Chlamydomonas sp. SAG25.89, by fusing specific cis-acting elements from its Actin gene with the gene providing hygromycin resistance and using an elaborated electroporation protocol. Like C. reinhardtii, Chlamydomonas sp. has a high GC content, allowing reporter genes and selection markers to be applicable in both organisms. Chlamydomonas sp. grows purely photoautotrophically and requires ammonia as a nitrogen source because its nuclear genome lacks some of the genes required for nitrogen metabolism. Interestingly, it can grow well under both low and very high salinities (up to 50 g · L-1) rendering it as a model for osmotolerance. We further show that Chlamydomonas sp. grows well from 15 to 28°C, but halts its growth at 32°C. The genome of Chlamydomonas sp. contains some gene homologs the expression of which is regulated according to the ambient temperatures and/or confer thermal acclimation in C. reinhardtii. Thus, knowledge of temperature acclimation can now be compared to the marine species. Furthermore, Chlamydomonas sp. can serve as a model for studying marine microbial interactions and for comparing mechanisms in freshwater and marine environments. Chlamydomonas sp. was previously shown to be immobilized rapidly by a cyclic lipopeptide secreted from the antagonistic bacterium Pseudomonas protegens PF-5, which deflagellates C. reinhardtii.},
keywords = {algae, bacteria, DNA / genomics, phylogenetics},
pubstate = {published},
tppubtype = {article}
}
The freshwater microalga Chlamydomonas reinhardtii, which lives in wet soil, has served for decades as a model for numerous biological processes, and many tools have been introduced for this organism. Here, we have established a stable nuclear transformation for its marine counterpart, Chlamydomonas sp. SAG25.89, by fusing specific cis-acting elements from its Actin gene with the gene providing hygromycin resistance and using an elaborated electroporation protocol. Like C. reinhardtii, Chlamydomonas sp. has a high GC content, allowing reporter genes and selection markers to be applicable in both organisms. Chlamydomonas sp. grows purely photoautotrophically and requires ammonia as a nitrogen source because its nuclear genome lacks some of the genes required for nitrogen metabolism. Interestingly, it can grow well under both low and very high salinities (up to 50 g · L-1) rendering it as a model for osmotolerance. We further show that Chlamydomonas sp. grows well from 15 to 28°C, but halts its growth at 32°C. The genome of Chlamydomonas sp. contains some gene homologs the expression of which is regulated according to the ambient temperatures and/or confer thermal acclimation in C. reinhardtii. Thus, knowledge of temperature acclimation can now be compared to the marine species. Furthermore, Chlamydomonas sp. can serve as a model for studying marine microbial interactions and for comparing mechanisms in freshwater and marine environments. Chlamydomonas sp. was previously shown to be immobilized rapidly by a cyclic lipopeptide secreted from the antagonistic bacterium Pseudomonas protegens PF-5, which deflagellates C. reinhardtii.