Retargeting a maize β-glucosidase to the vacuole--evidence from intact plants that zeatin-O-glucoside is stored in the vacuole
Jazyk angličtina Země Anglie, Velká Británie Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
22552277
DOI
10.1016/j.phytochem.2012.03.012
PII: S0031-9422(12)00145-8
Knihovny.cz E-zdroje
- MeSH
- beta-glukosidasa genetika metabolismus MeSH
- chloroplasty účinky léků metabolismus MeSH
- cytokininy metabolismus MeSH
- fazol genetika MeSH
- geneticky modifikované rostliny MeSH
- glukosidy metabolismus MeSH
- hybridizace genetická MeSH
- kukuřice setá enzymologie genetika MeSH
- semenáček cytologie účinky léků růst a vývoj MeSH
- tabák cytologie účinky léků genetika metabolismus MeSH
- vakuoly účinky léků genetika metabolismus MeSH
- zeatin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- beta-glukosidasa MeSH
- cytokininy MeSH
- glukosidy MeSH
- zeatin-O-glucoside MeSH Prohlížeč
- zeatin MeSH
Cytokinin (CK) activity is regulated by the complex interplay of their metabolism, transport, stability and cellular/tissue localization. O-glucosides of zeatin-type CKs are postulated to be storage and/or transport forms. Active CK levels are determined in part by their differential distribution of CK metabolites across different subcellular compartments. We have previously shown that overexpressing chloroplast-localized Zm-p60.1, a maize β-glucosidase capable of releasing active cytokinins from their O- and N3-glucosides, perturbs CK homeostasis in transgenic tobacco. We obtained tobacco (Nicotiana tabacum L., cv Petit Havana SR1) plants overexpressing a recombinant Zm-p60.1 that is targeted to the vacuole. The protein is correctly processed and localized to the vacuole. When grown on medium containing exogenous zeatin, transgenic seedlings rapidly accumulate fresh weight due to ectopic growths at the base of the hypocotyl. The presence of the enzyme in these ectopic structures is shown by histochemical staining. CK quantification reveals that these transgenic seedlings are unable to accumulate zeatin-O-glucoside to levels similar to those observed in the wild type. When crossed with tobacco overexpressing the zeatin-O-glucosyltransferase gene from Phaseolus, the vacuolar variant shows an almost complete reversion in the root elongation assay. This is the first evidence from intact plants that the vacuole is the storage organelle for CK O-glucosides and that they are available to attack by Zm-p60.1. We propose the use of Zm-p60.1 as a robust molecular tool that exploits the reversibility of O-glucosylation and enables delicate manipulations of active CK content at the cellular level.
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