Enhanced meristem development, tolerance to oxidative stress and hyposensitivity to nitric oxide in the hypermorphic...

Nitric oxide (NO) and reactive oxygen are common factors in multiple plant responses to stress, and their involvement in hypoxia-triggered responses is key to ensure growth under adverse environmental conditions. Here, we analyse the regulatory functions exerted by hypoxia-, NO- and oxidative stress-inducible Arabidopsis gene coding for the VQ motif-containing protein 10 (VQ10). A hypermorphic vq10-H mutant allowed identifying VQ10-exerted regulation on root and shoot development as well as its role in regulating responses to NO and oxidative stress. Enhanced VQ10 expression in vq10-H plants led to enhanced elongation of the primary root, and increased root cell division and meristem size during early postgermination development. In shoots, VQ10 activation of cell division was counteracted by WRKY33-exerted repression, thus leading to a dwarf bushy phenotype in plants with enhanced VQ10 expression in a wrky33 knock-out background. Low number of differentially expressed genes were identified when vq10-H versus Col-0 plants were compared either under normoxia or hypoxia. vq10-H and VQ10ox plants displayed less tolerance to submergence but, in turn, were more tolerant to oxidative stress and less sensitive to NO than wild-type plants. VQ10 could be a node integrating redox-related regulation on development and stress responses.