title: Carbonic anhydrase: a key regulatory and detoxifying enzyme for Karst plants.
abstract: Karstification is a rapid process during which calcidic stones/limestones undergo dissolution with the consequence of a desertification of karst regions. A slow-down of those dissolution processes of Ca-carbonate can be approached by a reforestation program using karst-resistant plants that can resist alkaline pH and higher bicarbonate (HCO₃⁻) concentrations in the soil. Carbonic anhydrases (CA) are enzymes that mediate a rapid and reversible interconversion of CO₂ and HCO₃⁻. In the present study, the steady-state expression of a CA gene, encoding for the plant carbonic anhydrase from the parsley Petroselinum crispum, is monitored. The studies were primarily been performed during germination of the seeds up to the 12/14-day-old embryos. The CA cDNA was cloned. Quantitative polymerase chain reaction (qPCR) analysis revealed that the gene expression level of the P. crispum CA is strongly and significantly affected at more alkaline pH in the growth medium (pH 8.3). This abolishing effect is counteracted both by addition of HCO₃⁻ and by addition of polyphosphate (polyP) to the culture medium. In response to polyP, the increased pH in the vacuoles of the growing plants is normalized. The effect of polyP let us to propose that this polymer acts as a buffer system that facilitates the adjustment of the pH in the cytoplasm. In addition, it is proposed that polyP has the potential to act, especially in the karst, as a fertilizer that allows the karstic plants to cope with the adverse pH and HCO₃⁻ condition in the soil.
authors.affiliation: ERC Advanced Investigator Grant Research Group, University Medical Center, Institute for Physiological Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 6, 55128, Mainz, Germany, wmueller@uni-mainz.de.
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
authors.forename: Li
authors.initials: L
authors.lastname: Qiang
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.forename: Natalie
authors.initials: N
authors.lastname: Hönig
authors.forename: Daoxian
authors.initials: D
authors.lastname: Yuan
authors.forename: Vlad A
authors.initials: VA
authors.lastname: Grebenjuk
authors.forename: Francesca
authors.initials: F
authors.lastname: Mussino
authors.forename: Marco
authors.initials: M
authors.lastname: Giovine
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001639:Bicarbonates / Q000378:metabolism / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination; D006863:Hydrogen-Ion Concentration; D008658:Inactivation, Metabolic; D008969:Molecular Sequence Data; D028528:Petroselinum / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000276:immunology; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011122:Polyphosphates / Q000494:pharmacology; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development
chemical_list: D001639:Bicarbonates; D010940:Plant Proteins; D011122:Polyphosphates; D002256:Carbonic Anhydrases