Identification Of Salt-induced Cis-acting Elements In BADH Promoter And Isolation Of Transcription Factors Interacting With The Cis-elements

Betaine aldehyde dehydrogenase (BADH) is the key enzyme for betaine synthesis, itsexpression is induced by salt. Our preliminary work found that BADH promoter fragment(-300bp to+62bp) from Suaeda liaotungensis K. possesses all the essential cis-acting elementsand is sufficient for NaCl induction. The purpose of this study is to find salt-inducedcis-acting elements in BADH promoter by bioinformatics analysis, to identify salt-inducedcis-acting elements by EMSA, to isolate the transcription factors interacting with thesalt-induced cis-acting elements by yeast one-hybrid system. This study will provide areliable reference and research basis for the study of salt induction promoter elements andtranscription factors. Specific work and results are as follows:1. BADH promoter fragment (-300bp to+62bp) was analyzed using Genomatix software, andabout 200 different elements were obtained. From these elements, we selected sevenpossible salt-induced cis-acting elements. They are named as PB1 (GT-1), PB2 (MYB),PB3 (NAC), PB4 (WRKY), PB5 (MYB ), PB6 (MYB), PB7 (G-box/MYC/ABA).2. 7 probes were designed using the selected cis-acting elements as the core sequence. Theinteraction between probes and nuclear proteins from Suaeda liaotungensis leaves wasdetected by EMSA, Blocking signals were found in 7 probes. It is concluded that PB1(GT-1 ), PB2 (MYB), PB3 (NAC), PB6 (MYB), PB7 (G-box/MYC/ABA) may be thesalt-induced cis-acting elements of BADH promoter.3. Using PB3 (NAC) as bait, 2 transcription factors were isolated from the cDNA library ofSuaeda liaotungensis by yeast one-hybrid experiments. They are drought/cold induciblegenes. They may be the transcription factors interacting with PB3.