Genome-wide identification and characterisation of telomerase reverse transcriptase gene in Ammopiptanthus mongolicus and overexpression of AmTERT-mediated abiotic stress tolerance in Escherichia coli

Telomerase is a ribonucleoprotein complex responsible for extending the telomeres. Telomerase reverse transcriptase (TERT) is the key component of telomerase. In this study, we characterised AmTERT in Ammopiptanthus mongolicus, a desert evergreen broadleaf shrub known for its high tolerance to harsh environments. AmTERT gene is located on chromosome 9, encoding 1153 amino acids with a molecular weight of 132.52 kDa, and is classified as a hydrophilic protein with relatively low stability. Synteny analysis was used to analyse the isogenic gene pairs of the TERT genes between A. mongolicus and three other species, suggesting that they descended from early dicotyledonous ancestors. Moreover, there are a large number of abiotic stress cis-elements in AmTERT promoter regions. To gain a deeper understanding of the abiotic stress capacity of AmTERT, it was transformed into Escherichia coli, and the fusion protein was purified. The overexpression of AmTERT enhanced tolerance to NaCl, mannitol, and hydrogen peroxide in E. coli. It is suggested that AmTERT is a candidate gene for genetic engineering of plant abiotic stress tolerance.