Functional Analysis Of Wheat Abiotic Stress Response Genes TabHLH39/44 And TabZIP15

bHLH and bZIP transcription factors are two kinds of important transcription factor families which play important roles in response to biotic and abiotic stresses. However, few studies on the functions of stress-related of bHLH and bZIP transcription factors have been done in wheat. On the basis of previous works, the characterization and expression pattern responsing to abiotic stress of TabHLH39, TabHLH44 and TabZIP15 were analyzed. To test their functions, the expression vectors of TabHLH39, TabHLH44 and TabZIP15 were generated and were transformed into Arabidopsis plants. Through abiotic stress resistance identification, measurements of physiological indices and gene expression analysis of abiotic stress-response genes, the roles of improvement tolerances to abiotic stresses in transgenic Arabidopsis plants were elucidated.TabHLH39 was a bHLH transcription factor of VIIa subfamily, which was located on the wheat chromosome 5DL. TabHLH39 was induced by salt and PEG stresses, and only slightly induced by cold stress and exogenous ABA treatment. The protein encoded by TabHLH39 was localized in the nucleus through transient expressed in tabacco epidermal cells, and possessed transcription activation activity in yeast. Overexpression of TabHLH39 led to enhance the resistance to drought, high salinity and freeze stresses in the transgenic Arabidopsis plants.TabHLH44 belonged to encoding a bHLH transcription factor of Ⅷb subfamily, which was mapped to the wheat chromosome 1AL. TabHLH44 was induced by salt, PEG, cold stresses and exogenous ABA treatment. The protein encoded by TabHLH44 was localized in the whole cell through transient expressed in tabacco epidermal cells, and possessed transcription activation activity in yeast. Overexpression of TabHLH44 resulted in enhanced tolerances to drought, high salinity and freeze stresses in transgenic Arabidopsis plants.TabZIP15 encoded a bZIP transcription factor of C subfamily, which was mapped to the wheat chromosome 7DL. TabZIP15 was induced by salt, PEG, cold stresses and exogenous ABA treatment. The protein encoded by Tab ZIP15 was localized in the nucleus through transient expressed in tabacco epidermal cells, and possessed transcription activation activity in yeast with an N-terminal transcriptional activation domain. Overexpression of TabZIP15 transgenic Arabidopsis plants improved the drought and freeze resistance of transgenic Arabidopsis plants. Yeast one-hybrid experiments showed, Tab ZIP15 transcription factor can bind to ABRE cis-acting elements. Yeast library screening experiments and luciferase complementation assay(LCI) showed, TabZIP15 transcription factors can combine with enolase TaENO-b, directly involving in the regulation of glycolysis and gluconeogenesis pathway, and can also combine with C2 domain protein encoded by AK251032.1 and FJ515827.1 separately.All the above TabHLH39、TabHLH44 and TabZIP15 transgenic Arabidopsis plants could improve the tolerances to abiotic stresses, which simultaneously demonstrated by enhanced expression of abiotic stress-response genes and exhibited a higher level of the content of soluble sugar and proline, and lower level of electrolyte leakage rate compared with WT plants under drought and salt stresses.