Zinc Excess Induces a Hypoxia-Like Response by Inhibiting Cysteine Oxidases in Poplar Roots.

Abstract

Poplar (Populus spp.) is a tree species considered for the remediation of soil contaminated by metals, including zinc (Zn). To improve poplar's capacity for Zn assimilation and compartmentalization, it is necessary to understand the physiological and biochemical mechanisms that enable these features as well as their regulation at the molecular level. We observed that the molecular response of poplar roots to Zn excess overlapped with that activated by hypoxia. Therefore, we tested the effect of Zn excess on hypoxia-sensing components and investigated the consequence of root hypoxia on poplar fitness and Zn accumulation capacity. Our results suggest that high intracellular Zn concentrations mimic iron deficiency and inhibit the activity of the oxygen sensors Plant Cysteine Oxidases, leading to the stabilization and activation of ERF-VII transcription factors, which are key regulators of the molecular response to hypoxia. Remarkably, excess Zn and waterlogging similarly decreased poplar growth and development. Simultaneous excess Zn and waterlogging did not exacerbate these parameters, although Zn uptake was limited. This study unveils the contribution of the oxygen-sensing machinery to the Zn excess response in poplar, which may be exploited to improve Zn tolerance and increase Zn accumulation capacity in plants.

• Authors: Laura Dalle Carbonare, Mark D White, Vinay Shukla, Alessandra Francini, Pierdomenico Perata, Emily Flashman, Luca Sebastiani, Francesco Licausi
• Journal: Plant physiology (Plant Physiol) Vol. 180 Issue 3 Pg. 1614-1628 (07 2019) ISSN: 1532-2548 [Electronic] United States
• PMID: 31019003 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2019 American Society of Plant Biologists. All Rights Reserved.

Chemical References

• Plant Proteins
• Cysteine Dioxygenase
• Zinc

Topics

• Adaptation, Physiological (genetics)
• Anaerobiosis
• Biodegradation, Environmental
• Cysteine Dioxygenase (genetics, metabolism)
• Gene Expression Regulation, Plant
• Intracellular Space (metabolism)
• Plant Proteins (genetics, metabolism)
• Plant Roots (genetics, metabolism)
• Populus (genetics, metabolism)
• Zinc (metabolism)