Genome-Wide Analysis of Homologous E6-AP Carboxyl-Terminal E3 Ubiquitin Ligase Gene Family in <i>Populus trichocarpa</i>

Abstract

Proteins containing the homologous E6-AP carboxyl-terminal (HECT) domain are a class of E3 ubiquitin ligases involved in the ubiquitin–proteasome pathway, which plays an irreplaceable role in plant growth, development, and stress resistance. However, a phylogenetic analysis and expression profile of the HECT gene (PtrHECT) in the model plant Populus trichocarpa (Torr. & Gray) have not been reported. In this study, we identified 13 PtrHECT genes using genome-wide analysis, and then these were divided into four groups. The protein interaction networks showed that the PtrHECT protein may interact with PTR6 and participate in ABA signal regulation. Abiotic stress is the main environmental factor limiting plant growth and development. The qRT-PCR results showed that PtrHECT1, 4, 7, 8, and 9 were significantly up-regulated in leaves at each time point under drought stress, and most PtrHECT genes responded to both drought and high salt stress, consistent with their promoter sequence analysis, revealing the presence of an important number of phytohormone-responsive and stress-related cis-regulatory elements. This study provides useful information for further analysis of the functions of the HECT gene family in P. trichocarpa.

Keywords

• expression analysis
• gene identification
• <i>HECT</i> genes family
• <i>Populus trichocarpa</i>