LSU network hubs integrate abiotic and biotic stress responses via interaction with the superoxide dismutase FSD2.

Abstract

In natural environments, plants often experience different stresses simultaneously, and adverse abiotic conditions can weaken the plant immune system. Interactome mapping revealed that the LOW SULPHUR UPREGULATED (LSU) proteins are hubs in an Arabidopsis protein interaction network that are targeted by virulence effectors from evolutionarily diverse pathogens. Here we show that LSU proteins are up-regulated in several abiotic and biotic stress conditions, such as nutrient depletion or salt stress, by both transcriptional and post-translational mechanisms. Interference with LSU expression prevents chloroplastic reactive oxygen species (ROS) production and proper stomatal closure during sulphur stress. We demonstrate that LSU1 interacts with the chloroplastic superoxide dismutase FSD2 and stimulates its enzymatic activity in vivo and in vitro. Pseudomonas syringae virulence effectors interfere with this interaction and preclude re-localization of LSU1 to chloroplasts. We demonstrate that reduced LSU levels cause a moderately enhanced disease susceptibility in plants exposed to abiotic stresses such as nutrient deficiency, high salinity, or heavy metal toxicity, whereas LSU1 overexpression confers significant disease resistance in several of these conditions. Our data suggest that the network hub LSU1 plays an important role in co-ordinating plant immune responses across a spectrum of abiotic stress conditions.

• Authors: Antoni Garcia-Molina, Melina Altmann, Angela Alkofer, Petra M Epple, Jeffery L Dangl, Pascal Falter-Braun
• Journal: Journal of experimental botany (J Exp Bot) Vol. 68 Issue 5 Pg. 1185-1197 (02 01 2017) ISSN: 1460-2431 [Electronic] England
• PMID: 28207043 (Publication Type: Journal Article)
• Copyright: © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Chemical References

• Arabidopsis Proteins
• LSU1 protein, Arabidopsis
• Nuclear Proteins
• Sulfur
• Superoxide Dismutase

Topics

• Arabidopsis (genetics, immunology, microbiology)
• Arabidopsis Proteins (genetics, metabolism)
• Disease Resistance (immunology)
• Gene Expression Regulation, Plant
• Nuclear Proteins (genetics, metabolism)
• Plant Diseases (immunology, microbiology)
• Pseudomonas syringae (physiology)
• Stress, Physiological
• Sulfur (metabolism)
• Superoxide Dismutase (genetics, metabolism)