A Basic Helix-Loop-Helix Gene from Poplar is Regulated by a Basic Leucine-Zipper Protein and is Involved in the ABA-Dependent Signaling Pathway
- 470 Downloads
Basic helix-loop-helix (bHLH) transcription factors (TF) comprise a large group of proteins that are involved in many developmental and physiological processes in plants. In this study, a bHLH gene (PkbHLH2), along with its promoter, was cloned from Populus koreana Rehd. A PkbHLH2 promoter::GUS gene fusion construct was generated to investigate the expression of PkbHLH2. The results demonstrated that PkbHLH2 was expressed mainly in leaf stalks, leaf veins and roots. Yeast one-hybrid assays showed that a bZIP gene product (PkbZIP2) can bind specifically to the ABA-responsive elements (ABRE) that exist in the promoter region of PkbHLH2, regulating the expression of PkbHLH2. In addition, the “GC” of the ABRE core motif “ACGTG” was very important for PkbZIP2 recognition, because its mutation to “TT” completely prevented the interaction between PkbZIP2 and ABRE. Furthermore, both PkbHLH2 and PkbZIP2 can be up-regulated by abscisic acid (ABA) and osmotic stress, and share similar expression patterns when exposed to ABA and osmotic stress. These results suggest that PkbZIP2 is an upstream regulator of PkbHLH2, which can control the expression of PkbHLH2 through an ABA-dependent signaling pathway.
KeywordsABA-dependent signaling pathway ABRE motif bHLH bZIP Populus koreana
This work was supported by National Natural Science Foundation of China (31000312).
- Doyle JJ, Doyle JL (1987) A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochem Bull 19:11–15Google Scholar
- Fernández-Calvo P, Chini A, Fernández-Barbero G, Chico JM, Gimenez-Ibanez S, Geerinck J, Eeckhout D, Schweizer F et al (2011) The Arabidopsis bHLH transcription factors MYC3 and MYC4 are targets of JAZ repressors and act additively with MYC2 in the activation of jasmonate responses. Plant Cell 23:701–715PubMedCrossRefGoogle Scholar
- Qi T, Song S, Ren Q, Wu D, Huang H, Chen Y, Fan M, Peng W et al (2011) The Jasmonate-ZIM-domain proteins interact with the WD-Repeat/bHLH/MYB complexes to regulate jasmonate-mediated anthocyanin accumulation and trichome initiation in Arabidopsis thaliana. Plant Cell 23:1795–1814PubMedCrossRefGoogle Scholar
- Zhang H, Hedhili S, Montiel G, Zhang Y, Chatel G, Pré M, Gantet P, Memelink J (2011a) The basic helix–loop–helix transcription factor CrMYC2 controls the jasmonate–responsive expression of the ORCA genes that regulate alkaloid biosynthesis in Catharanthus roseus. Plant J 67:61–71PubMedCrossRefGoogle Scholar