Abstract:Doubletrihelix genes play important roles in promoting morphogenesis and resistance to stress. In order to identify their function in tomato, we tested the expression patterns and responses of five doubletrihelix genes in different tissues, to phytohormones and abiotic stress by bioinformatics and expression analysis. Experimental results showed that: (1) five members and their species specificity were determined in tomato by bioinformatics analysis. (2) Expression pattern analysis showed that SlGTL3 specifically expressed in root and stem and others high in fruits by means of qRTPCR, suggesting the tissues specificity of doubletrihelix genes in AC++. (3) Hormoneinduced test displayed that SlGTL5 responds to four kind of phyhormones very quickly and SlGTL1 is only induced by ABA. (4) It was proved that expression levels of SlGTL3 and SlGTL5 can be altered by salt, SlGTL3-SlGTL5 by extreme temperature, SlGTL3 and SlGTL5 by mechanical wounding, and SlGTL1, SlGTL4, SlGTL5 by dehydration. The results indicated that SlGTL3 function is correlated with plant morphogenesis and abiotic stress, while others to fruits development. Our study also suggested that SlGTL1 is related with ABA signaling and SlGTL5 with signaling transmission as the result of its fast responses to various exogenous hormones.