EIN3 interferes with the sulfur deficiency signaling in Arabidopsis thaliana through direct interaction with the SLIM1 transcription factor

tSulfur deficiency in plants leads to metabolic reprogramming through changes of gene expression. SLIM1is so far the only characterized transcription factor associated strictly with sulfur deficiency stress inArabidopsis thaliana. It belongs to the same protein family as EIN3, a major positive switch of ethylenesignaling pathway. It binds to the specific cis sequence called UPE-box. Here we show that SLIM1 interactswith UPE-box as a homodimer. Interestingly, the same region of the protein is used for heterodimerizationwith EIN3; however, the heterodimer is not able to recognize UPE-box. Expression of several SLIM1-dependent genes is enhanced in sulfur deficiency grown Arabidopsis ein3-1 seedlings (with mutatedEIN3 protein). This implies a possible regulatory mechanism of ethylene in sulfur metabolism throughdirect EIN3-SLIM1 interaction