<i>Raphidiopsis mediterranea</i> (Nostocales) exhibits a flexible growth strategy under light and nutrient fluctuations in contrast to <i>Planktothrix agardhii</i> (Oscillatoriales)
<i>Raphidiopsis mediterranea</i> is a freshwater cyanobacterium that forms toxic blooms in eutrophic water bodies. Factors controlling its proliferation have not been explored in detail. We investigated <i>R. mediterranea</i> autecology by (i) analyzing its dynamics in a hype...
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| Autores principales: | , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2019
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/134709 |
| Aporte de: |
| Sumario: | <i>Raphidiopsis mediterranea</i> is a freshwater cyanobacterium that forms toxic blooms in eutrophic water bodies. Factors controlling its proliferation have not been explored in detail. We investigated <i>R. mediterranea</i> autecology by (i) analyzing its dynamics in a hypertrophic shallow lake dominated by <i>Planktothrix agardhii</i> (Oscillatoriales) and its relationship with environmental factors; and (ii) studying the effect of light intensity and phosphate availability on <i>R. mediterranea</i> isolates growing in mono or in co-cultures with <i>P. agardhii</i>. The redundancy analysis demonstrated that water temperature, light, and phosphate concentrations were important driving factors for the seasonal succession of the two species. When grown together with <i>P. agardhii</i>, <i>R. mediterranea</i> growth was strongly promoted under the highest light intensity treatment. On the other hand, in monoalgal cultures under phosphorus starvation, both strains exhibited a significant increase in total alkaline phosphatase activity, and changes in the expression of homologs to <i>phoA</i>-like and <i>phoD</i> genes (members of the Pho regulon). However, <i>R. mediterranea</i> showed higher phosphatase activity than <i>P. agardhii</i>, suggesting greater tolerance to phosphate limitation. Taken together, we conclude that physiological features of <i>R. mediterranea</i> play an important role in the coexistence with <i>P. agardhii</i> under environmental changes. |
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