Published in:
Plant, Cell & Environment, 36 (2013) 6, Seite 1093-1104
Language:
English
DOI:
10.1111/pce.12041
ISSN:
0140-7791;
1365-3040
Origination:
Footnote:
Description:
The aim of the ms was to better understand the Zn‐sensitive phenotype obtained as a result of expression of AtHMA4 (coding for a Zn‐export protein) in tobacco. We found that due to AtHMA4 expression the apoplast is overloaded with Zn, and development of necrosis (symptom of Zn toxicity) is related to the Zn concentration in the apoplast, and not to the Zn concentration in leaves. It was hypothesized that the Zn concentration is ‘sensed’ in the apoplast; when apoplastic Zn levels exceed a threshold, a signal is generated which initiates mechanisms leading to loading of Zn excess into a compact groups of cells which eventually die resulting in necrosis. Thus the appearance of necrosis on one hand is a symptom of Zn toxicity, but on the other could be regarded as a defense mechanism initiated when a plant faces high Zn toxicity.