Identification of the U-box gene family in peach (Prunus persica) and functional analysis of PpPUB20 in response to salt stress

Huiwen Zhang^1,2Ruxuan Guo²Xiaoshuang Zhang²Chongyu Zhao²Junkai Wu²Xiao Xiao²Yanhong Shen²Chunsheng Liu²Gang Li²Kai Su²Kun Xiao²Chenguang Zhang^2*Libin Zhang^2*

• ¹河北科技师范学院, 河北省, China
• ²Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province, China

Plant U-box protein (PUB) is an E3 ubiquitin ligase family, widely involved in various stress-response processes. However, the biological of PUB members in peach specieshave not yet been reported. In this study, 51 U-box protein genes (PUB) were identified in the cultivated peach "SJZX" and divided into six groups. Most of the PpPUB were predicted to be located in the nucleus and chloroplasts. Promoter analyses indicated that most members may be associated with light-responsive processes. Expression analysis based on RT-qPCR showed that most PUB members in peach were highly expressed in a certain tissues or organs.Based on the results of RT-qPCR expression analysis of 18 representative PpPUB after abiotic stress and hormone induction, all detected genes except for PpPUB19 were induced by salt stress， and PpPUB3/20/23/49 were induced by low temperature.Multiple genes were induced or repressed by exogenous hormone treatments. Furthermore, Arabidopsis seedlings heterologously overexpressing PpPUB20 exhibited greater salt tolerance than wild-type seedlings under the same salt stress conditions. These findings provide comprehensive information on the PpPUB family and identify PpPUB members that may be involved in the regulation of hormones and salt stress. Therefore, this study enhances the understanding of potential role of PpPUB in stress adaptation in peach, thereby establishing a foundation for subsequent functional investigations and applications in stress-resistant crop breeding.