Expression of HvHMA2 in tobacco modifies ZnaFeaCd homeostasis

HvHMA2 is a plasma membrane P1B-ATPase from barley that functions in Zn/Cd root-to-shoot transport. To assess the usefulness of HvHMA2 for modifying the metal content in aerial plant parts, it was expressed in tobacco under the CaMV35S promoter. Transformation with HvHMA2 did not produce one unique...

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Bibliographic Details
Published in:Journal of plant physiology 2013-09, Vol.170 (13), p.1176-1186
Main Authors: Barabasz, Anna, Wilkowska, Anna, Tracz, Katarzyna, RuszczyAska, Anna, Bulska, Ewa, Mills, Rebecca, Williams, Lorraine, Antosiewicz, Danuta
Format: Article
Language:English
Subjects:
Cadmium
Exports
Iron
Membranes
Tobacco
Tolerances
Uptakes
Zinc
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Summary:HvHMA2 is a plasma membrane P1B-ATPase from barley that functions in Zn/Cd root-to-shoot transport. To assess the usefulness of HvHMA2 for modifying the metal content in aerial plant parts, it was expressed in tobacco under the CaMV35S promoter. Transformation with HvHMA2 did not produce one unique pattern of Zn and Cd accumulation; instead it depended on external metal supply. Thus Zn and Cd root-to-shoot translocation was facilitated, but not at all applied Zn/Cd concentrations. Metal uptake was restricted in HvHMA2-transformed plants and the level in the shoot was not enhanced. It was shown that HvHMA2 localizes to the plasma membrane of tobacco cells, and overloads the apoplast with Zn, which could explain the overall decrease in metal uptake observed. Despite the lower levels in the shoot, HvHMA2 transformants showed increased Zn sensitivity. Moreover, introduction of HvHMA2 into tobacco interfered with Fe metabolism and Fe accumulation was modified in HvHMA2-transformants in a Zn- and Cd-concentration dependent manner. The results indicate that ectopic expression of the export protein HvHMA2 in tobacco interferes with tobacco metal ZnaCdaFe cross-homeostasis, inducing internal mechanisms regulating metal uptake and tolerance.
ISSN:0176-1617
DOI:10.1016/j.jplph.2013.03.018