Abstract:

【Objective】High mobility group（HMG）proteins participate in the regulation of DNA structure and chromatin, which play an important role in gene transcription regulation. Identifying the family of HMG genes in spinach（Spinacia oleracea L.）may provide a theoretical basis for studying the biological functions of spinach HMG proteins.【Method】The members of the spinach SoHMG family were identified at the whole genome level, and their physicochemical properties, gene structure, conserved motifs, promoter elements, and salicylic acid-responsive expression profiles were analyzed. 【Result】The spinach genome contained 16 members of the SoHMG gene family, with a coding region length of 240-4 029 bp and a coding amino acid number between 79-1 342. The 16 SoHMG genes were scattered across six chromosomes. By evolutionary tree analysis, SoHMG members were divided into two subfamilies, including three members in A subfamily and 13 in B subfamily. The members of the same subfamily have similar conserved domains. Some hormone-responsive elements, such as salicylic acid（SA）, were found in the promoter of the SoHMGB subfamily. The SoHMG genes were expressed in the roots, stems, and leaves of spinach. Most of genes had higher expressions in the leaves. SA treatment induced the expressions of most of the SoHMG genes. Among them, the expressions of SoHMGB1（SOV1g000250.1）, SoHMGB7（SOV5g026260.1）, and SoHMGB2（SOV1g027200.1）were more than 10 times higher than those in control. 【Conclusion】There are 16 members of HMG gene family in spinach genome, which is divided into 2 subfamilies. Three genes（（SoHMGB1, SoHMGB7, and SoHMGB2））are significantly upregulated under SA treatment, which may play an important role in the SA signal response.

Key words: spinach, HMG, identification, salicylic acid, gene expression