Impact of Nitrogen Sources on Gene Expression and Toxin Production in the Diazotroph <i>Cylindrospermopsis</i> <i>raciborskii</i> CS-505 and Non-Diazotroph <i>Raphidiopsis brookii</i> D9

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dc.contributor.authorStucken, Karina
dc.contributor.authorJohn, Uwe
dc.contributor.authorCembella, Allan
dc.contributor.authorSoto-Liebe, Katia
dc.contributor.authorVasquez, Monica
dc.date.accessioned2025-01-23T21:45:16Z
dc.date.available2025-01-23T21:45:16Z
dc.date.issued2014
dc.description.abstractDifferent environmental nitrogen sources play selective roles in the development of cyanobacterial blooms and noxious effects are often exacerbated when toxic cyanobacteria are dominant. Cylindrospermopsis raciborskii CS-505 (heterocystous, nitrogen fixing) and Raphidiopsis brookii D9 (non-N2 fixing) produce the nitrogenous toxins cylindrospermopsin (CYN) and paralytic shellfish toxins (PSTs), respectively. These toxin groups are biosynthesized constitutively by two independent putative gene clusters, whose flanking genes are target for nitrogen (N) regulation. It is not yet known how or if toxin biosynthetic genes are regulated, particularly by N-source dependency. Here we show that binding boxes for NtcA, the master regulator of N metabolism, are located within both gene clusters as potential regulators of toxin biosynthesis. Quantification of intra-and extracellular toxin content in cultures at early stages of growth under nitrate, ammonium, urea and N-free media showed that N-sources influence neither CYN nor PST production. However, CYN and PST profiles were altered under N-free medium resulting in a decrease in the predicted precursor toxins (doCYN and STX, respectively). Reduced STX amounts were also observed under growth in ammonium. Quantification of toxin biosynthesis and transport gene transcripts revealed a constitutive transcription under all tested N-sources. Our data support the hypothesis that PSTs and CYN are constitutive metabolites whose biosynthesis is correlated to cyanobacterial growth rather than directly to specific environmental conditions. Overall, the constant biosynthesis of toxins and expression of the putative toxin-biosynthesis genes supports the usage of qPCR probes in water quality monitoring of toxic cyanobacteria.
dc.fuente.origenWOS
dc.identifier.doi10.3390/toxins6061896
dc.identifier.issn2072-6651
dc.identifier.urihttps://doi.org/10.3390/toxins6061896
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/101708
dc.identifier.wosidWOS:000338190400012
dc.issue.numero6
dc.language.isoen
dc.pagina.final1915
dc.pagina.inicio1896
dc.revistaToxins
dc.rightsacceso restringido
dc.subjectcyanobacteria
dc.subjectCylindrospermopsis
dc.subjectRaphidiopsis
dc.subjectcylindrospermopsin
dc.subjectsaxitoxin
dc.subjectnitrogen
dc.subjectgene expression
dc.subject.ods14 Life Below Water
dc.subject.ods06 Clean Water and Sanitation
dc.subject.ods15 Life on Land
dc.subject.ods13 Climate Action
dc.subject.odspa14 Vida submarina
dc.subject.odspa06 Agua limpia y saneamiento
dc.subject.odspa15 Vida de ecosistemas terrestres
dc.subject.odspa13 Acción por el clima
dc.titleImpact of Nitrogen Sources on Gene Expression and Toxin Production in the Diazotroph <i>Cylindrospermopsis</i> <i>raciborskii</i> CS-505 and Non-Diazotroph <i>Raphidiopsis brookii</i> D9
dc.typeartículo
dc.volumen6
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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