The VQ motif-containing PoVQ31 protein positively modulates drought stress tolerance in Paeonia ostii 'FengDan'

Abstract

VQ proteins are transcription co-regulators that play important roles in plant growth, development, and response to biotic and abiotic stresses. However, the specific relationship between VQ proteins and drought stress has not been thoroughly studied in Paeonia ostii 'Fengdan'. In this study, PoVQ31 was successfully cloned, a gene with a total length of 540 bp and encoding 179 amino acids. Through bioinformatics analysis, the sequence characteristics, physical and chemical properties, and spatial structure were analyzed. It was observed that PoVQ31 had a typical VQ motif and was localized in the nucleus. Furthermore, its expression could be significantly upregulated in response to drought stress. PoVQ31-silenced lines showed more drought sensitivity compared to controls. Experiments further showed that transgenic lines had decreased leaf water content, but relative electrical conductivity (REC) and malondialdehyde (MDA) content increased compared with controls under drought stress conditions. The nitroblue tetrazolium (NBT) and diaminobenzidine (DAB) staining results showed that the transgenic plants accumulated excess reactive oxygen species (ROS). Meanwhile, the reduced antioxidant enzyme activity in PoVQ31-silenced plants prevented them from scavenging excessively accumulated ROS. All these results suggested that PoVQ31 might be involved in the activation of the ROS scavenging system, which in turn positively regulated the tolerance of Paeonia ostii 'Fengdan' to drought stress. This study provided novel insights into the function of VQ proteins and further enriched the understanding of this important protein in Paeonia ostii 'Fengdan'.

Keywords

• paeonia ostii 'fengdan'
• drought stress
• vq31
• reactive oxygen species