MeJA-inducible expression of the heterologous JAZ2 promoter from Arabidopsis in Populus trichocarpa protoplasts

Plant hormone jasmonates play an important role in the response of plants to environmental stress. Jasmonate ZIM-domain (JAZ) family proteins are key elements in the jasmonate signaling pathway. In Arabidopsis thaliana (Arabidopsis), the JAZ2 (At1g74950) gene expresses at a low level in the entire plant, but the response can be strongly and quickly induced by MeJA. The promoter sequence (1389 bp) of JAZ2 from Arabidopsis genome was cloned and linked to a GFP reporter gene, and we then investigated the transient expression of GFP in Populus trichocarpa :protoplasts. After treating the transformed protoplasts with MeJA, we observed the GFP fluorescence and quantified its mRNA transcription level. The results showed that the Arabidopsis JAZ2 promoter was able to drive GFP expression, and also responded to MeJA in Populus trichocarpa mesophyll protoplasts. The analysis of promoter sequences of JAZ gene family members showed that there were several conserved motifs, which were related to jasmonate signaling, such as G-box (CACGTG), CGTCA-motif (CGTCA) and TGACG-box (TGACG), and also some known cis-acting regulatory elements involved in other aspects, however the function of these motifs still needs further study.