Basic helixloophelix (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 geneSpbHLH89 (Sol Genomics number Sopen04g001150) from Solanum pennellii. Meanwhile, we also analyzed its expression patterns under drought stress by qRTPCR 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 basichelixbasic 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) qRTPCR analysis showed that the pattern of SpbHLH89 was highly expressed in flowers and also induced by drought stress. (3) SDSPAGE and Western blotting analysis showed that the molecular weight of pET30aSpbHLH89 was approximately 31 kD. (4) Heteroexpression of the pET30aSpbHLH89 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.