Abstract:Glycosyltransferase can maintain the hormone balance in plants and widely participate in plant growth and development and stress response. PhUGT74E2, the homologous gene of UGT74E2 and its promoter sequence were cloned from petunia (Petunia hybrida var. Mitchel diploid). The sequence characteristics and protein structure characteristics were analyzed,to study the function of petunia UGT74E2, and laid a theoretical foundation for further research on the function of PhUGT74E2 and its molecular mechanism regulating the stress tolerance of petunia. The results showed: (1) the homologous gene of UGT74E2 was cloned from petunia (Petunia hybrida var. Mitchel diploid), named PhUGT74E2. (2) The full length of PhUGT74E2 was 1 986 bp, encoding 448 amino acids. The molecular formula of the protein was speculated to be C2278H3544N586O676S18. The molecular weight was 50.53 kD and the isoelectric point was 5.18. No signal peptide and transmembrane domain were found in PhUGT74E2, and the protein was mainly located in chloroplast. The promoter sequence of 2 083 bp upstream of PhUGT74E2 gene was also cloned. The sequence contains abscisic acid, gibberellin, light and stress response elements. (3) Phylogenetic tree analysis showed that PhUGT74E2 had the same origin as other species, but was most closely related to tobacco NtUGT74E2. (4) Fluorescence quantitative PCR analysis showed that PhUGT74E2 gene was expressed in leaves, stems, roots, axil and apical. The expression level of PhUGT74E2 in axil was the highest, while the lowest in stems and roots. Both PEG6000 and NaCl treatments caused significant upregulation of PhUGT74E2 expression, and the expression level increased with time. The result indicated that PhUGT74E2 was involved in drought and salt stress response of petunia.