A Ramie bZIP Transcription Factor BnbZIP2 Is Involved in Drought, Salt, and Heavy Metal Stress Response

Abstract

bZIP transcription factors play key roles in plant growth, development, and stress signaling. A bZIP gene BnbZIP2 (GenBank accession number: KP642148) was cloned from ramie. BnbZIP2 has a 1416 base pair open reading frame, encoding a 471 amino acid protein containing a characteristic bZIP domain and a leucine zipper. BnbZIP2 shares high sequence similarity with bZIP factors from other plants. The BnbZIP2 protein is localized to both nuclei and cytoplasm. Transcripts of BnbZIP2 were found in various tissues in ramie, with significantly higher levels in female and male flowers. Its expression was induced by drought, high salinity, and abscisic acid treatments. Analysis of the cis-elements in promoters of BnbZIP2 identified cis-acting elements involved in growth, developmental processes, and a variety of stress responses. Transgenic Arabidopsis plants' overexpression of BnbZIP2 exhibited more sensitivity to drought and heavy metal Cd stress during seed germination, whereas more tolerance to high-salinity stress than the wild type during both seed germination and plant development. Thus, BnbZIP2 may act as a positive regulator in plants' response to high-salinity stress and be an important candidate gene for molecular breeding of salt-tolerant plants.

A Soybean bZIP Transcription Factor GmbZIP19 Confers Multiple Biotic and Abiotic Stress Responses in Plant

“…Previously, studies showed that various bZIP genes were involved in regulating plant response to abiotic stresses such as salt, drought and low temperature, etc. [13,39]. Overexpression of TabZIP60 in wheat confers multiple abiotic stress tolerances [13], and overexpression of TaWRKY2 could increase drought tolerance of transgenic wheat [40].…”

Revisiting the Role of Plant Transcription Factors in the Battle against Abiotic Stress

“…Similarly, GhABF2 from cotton has been shown to facilitate drought and salt stress tolerance in transgenic cotton through an ABA-dependent pathway, as supported by higher antioxidant enzyme activities and proline content in transgenic plants under drought and salt stress [ 78 ]. In addition, functional analysis of grape ( Vitis vinifera ) VvbZIP23 [ 161 ], lotus root ( Nelumbo nucifera ) LrbZIP [ 162 ], T. hispida ThbZIP [ 163 ], and ramie ( Boehmeria nivea ) BnbZIP2 [ 79 ] genes demonstrated that all these bZIP TFs play critical roles in regulating salt stress along with other abiotic stresses.…”

Regulation Mechanisms of Plant Basic Leucine Zippers to Various Abiotic Stresses

“…Under drought stress, the transgenic Arabidopsis plants of IbbZIP1 showed significant upregulation of the genes involved in ABA and proline biosynthesis and reactive oxygen species scavenging system, so as to significantly decrease of H 2 O 2 content (Kang et al, 2019). During seed germination and plant development, transgenic ramie plants overexpressing BnbZIP2 were more sensitive to drought stress than wild-type (Huang et al, 2016). In addition, overexpression of transcription factors such as Arabidopsis thaliana ABF3 (Wang Z. et al, 2016) and wheat TabZIP60 (Zhang L. N. et al, 2015) in plants can significantly improve the drought resistance of transgenic plants.…”