Abstract:Basic helixloophelix (bHLH) transcription factors are one of the largest transcription factor families in plants. It is extensively involved in stress response of plants. In the present study, we cloned a bHLH transcription factor geneSpbHLH89 (Sol Genomics number Sopen04g001150) from Solanum pennellii. Meanwhile, we also analyzed its expression patterns under drought stress by qRTPCR and verified its biological function by prokaryotic expression. The results showed that: (1) an open reading frame (ORF) of SpbHLH89 was obtained from S. pennellii, which is 684 bp long and encodes 227 amino acids with typical basichelixbasic domain and mainly located on the nucleus. Phylogenetic tree analysis showed that SpbHLH89 was highly conserved and shared a high degree of sequence similarity with NtbHLLH094 from Nicotiana tomentosiformis. (2) qRTPCR analysis showed that the pattern of SpbHLH89 was highly expressed in flowers and also induced by drought stress. (3) SDSPAGE and Western blotting analysis showed that the molecular weight of pET30aSpbHLH89 was approximately 31 kD. (4) Heteroexpression of the pET30aSpbHLH89 could improve the growth of the recombinant strain of E. coli BL21(DE3) under salt (400 mmol/L NaCl) and drought (600 mmol/L mannitol) stress. Taken together, the heterologous expression of SpbHLH89 transcription factor could improve the tolerance of recombinant bacteria to abiotic stress.