Abstract: DEAD-box RNA helicases, which function as the RNA chaperones, are involved in RNA metabolism, including pre-mRNA splicing, ribosome biogenesis, RNA degradation and gene expression. In addition, they also play important roles in plant development and stress tolerance. A DEAD-box homologous protein was selected from the NCBI database by means of program of homologous alignment according to the published DEAD-box protein in Arabidopsis thaliana and maize and named SlDEAH1, then the specific primers, which being used to amplify the cDNA sequences of SlDEAH1 from wild type tomato AC⁺⁺, were designed according to the DNA corresponding sequences. Bioinformatics analysis, expression pattern, stress and hormone treatments were used to study the DEAD-box gene SlDEAH1. The results showed that the open reading frame of SlDEAH1 was 2 073 bp, encoding 690 amino acid residues. In the protein of SlDEAH1, 9 conserved motifs were found to be essential for the helicase activities such as ATP binding, ATP hydrolysis and RNA binding. RT-PCR expression pattern analysis showed that SlDEAH1 may play important roles in sepal and leaf development and fruit ripening. High temperature, low temperature, dehydration, wounding and salt stress induced the expression of SlDEAH1 in different degrees in leaves, but its expression in roots was obviously inhibited by salt stress. Furthermore, the expression of SlDEAH1 was also induced in different degrees by ABA, ACC, IAA, GA₃, MeJA and ZT, and the inductive effect of ABA was the most obvious. These results lay a foundation for further study on the physiological function of SlDEAH1 in the development and stress response of Solanum lycopersicum.

Key words: Solanum lycopersicum, DEAD-box RNA helicases, SlDEAH1, stress, hormone, RT-PCR analysis