Abstract:

The 2 211 bp CDS sequence of PbTMT4 gene（Pbr032130.1）and the promoter sequence of 1 220 bp upstream of the transcription initiation site were obtained using Pyrus bretschneideri‘Dangshan Suli’as the material based on the pear genome database. When the PbTMT4 gene was introduced into Arabidopsis by Agrobacterium-mediated method，the growth rate of transgenic Arabidopsis was faster，and the flowering time was earlier than the wild type. At the same time，the amount of sugar accumulation in transgenic Arabidopsis was significantly higher than that in wild type. Bioinformatics analysis indicated that the promoter contains multiple cis-acting elements associated with stress response，hormone signals and light signals. To further analyze the promoter function of PbTMT4 gene，a promoter-reporter vector was constructed and transformed into Arabidopsis. Analysis of T3 transgenic Arabidopsis tissues with histochemical staining and semi-quantitative analysis showed that GUS gene was expressed in roots，stems，leaves，flowers and fruit pod. And sodium chloride（NaCl），drought，gibberellin（GA3），methyl jasmonate（MeJA）and light intensity can induce the transcription level of GUS gene in Arabidopsis to some extent. Stress treatment revealed that the PbTMT4 gene overexpression transgenic line had less damage than the wild type plants. The results of the study preliminarily suggest that PbTMT4 gene can promote the development of transgenic plants and increase sugar accumulation，and may play an important regulatory role in the abiotic stress.

Key words: Pyrus bretschneideri, promoter, sugar, tonoplast monosaccharide transporter, GUS gene