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The bZIP protein from Tamarix hispida, ThbZIP1, is ACGT elements binding factor that enhances abiotic stress signaling in transgenic Arabidopsis.

Ji X, Liu G, Liu Y, Zheng L, Nie X, Wang Y - BMC Plant Biol. (2013)

Bottom Line: Two MYCs were found to bind to E-box, in the promoter of ThbZIP1 to activate its expression.Compared with wild-type (Col-0) Arabidopsis, transgenic plants expressing ThbZIP1 had an increased tolerance to drought and salt, but had an increased sensitivity to ABA during seed germination and root growth; meanwhile, ROS level, cell death and water loss rate in transgenic plants were significantly reduced.Based on these data, we suggest that ThbZIP1 confers abiotic stress tolerance through activating stress tolerance genes to modulate ROS scavenging ability and other physiological changes involved in stress tolerance, and plays an important role in the ABA-mediated stress response of T. hispida.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, 150040 Harbin, China. ychngwang@yahoo.com.

ABSTRACT

Background: Tamarix spp. are woody halophyte, which are very tolerant to abiotic stresses such as salinity and drought, but little is known about their specific stress response systems. Basic leucine zipper proteins (bZIPs) play important roles in the ability of plants to withstand adverse environmental conditions. However, their exact roles in abiotic stress tolerance are still not fully known. In the current study, we functionally characterized a bZIP gene (ThbZIP1) from Tamarix hispida in response to abiotic stresses.

Results: We addressed the regulatory network of ThbZIP1 in three levels, i.e. its upstream regulators, the cis-acting elements recognized by ThbZIP1, and its downstream target genes. Two MYCs were found to bind to E-box, in the promoter of ThbZIP1 to activate its expression. Expression of ThbZIP1 is induced by ABA, salt, drought, methyl viologen and cold. ThbZIP1 can specifically bind to ACGT elements, with the highest binding affinity to the C-box, followed by the G-box and lastly the A-box. Compared with wild-type (Col-0) Arabidopsis, transgenic plants expressing ThbZIP1 had an increased tolerance to drought and salt, but had an increased sensitivity to ABA during seed germination and root growth; meanwhile, ROS level, cell death and water loss rate in transgenic plants were significantly reduced. Microarray analyses showed that many ROS scavenging genes were up-regulated by ThbZIP1 under salt stress conditions.

Conclusions: Based on these data, we suggest that ThbZIP1 confers abiotic stress tolerance through activating stress tolerance genes to modulate ROS scavenging ability and other physiological changes involved in stress tolerance, and plays an important role in the ABA-mediated stress response of T. hispida.

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Model of the regulatory network of ThbZIP1 involved in abiotic stress responses. Stress signals such as ABA are produced in plants when exposed to abiotic stressors, and the expression of MYC is induced by stress signals; then the MYC proteins bind to the E-box motif in the promoter of ThbZIP1 to activate the expression of ThbZIP1. The ThbZIP1 in turn binds to the A-, C- or G-box in the promoter of the genes to alter their expression, resulting that abiotic stress tolerances are improved in plants.
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Figure 7: Model of the regulatory network of ThbZIP1 involved in abiotic stress responses. Stress signals such as ABA are produced in plants when exposed to abiotic stressors, and the expression of MYC is induced by stress signals; then the MYC proteins bind to the E-box motif in the promoter of ThbZIP1 to activate the expression of ThbZIP1. The ThbZIP1 in turn binds to the A-, C- or G-box in the promoter of the genes to alter their expression, resulting that abiotic stress tolerances are improved in plants.

Mentions: Based on all the experimental data presented here, a model is proposed to explain the ThbZIP1-mediated salt tolerance (FigureĀ 7). Stress signals such as ABA are generated during abiotic stresses, which activate the expression of the transcription factors including MYC; then, the MYC proteins bind to E-box motifs in the ThbZIP1 promoter to induce its expression. Combined with the stress signals, the activated ThbZIP1 in turn binds to the A-, C- or G-box motifs in the promoters of genes to activate their expression, leading to the improvement of abiotic stress tolerance in plants. Therefore, ThbZIP1 is a factor in modulating abiotic stress responses through an ABA-dependent signaling pathway.


The bZIP protein from Tamarix hispida, ThbZIP1, is ACGT elements binding factor that enhances abiotic stress signaling in transgenic Arabidopsis.

Ji X, Liu G, Liu Y, Zheng L, Nie X, Wang Y - BMC Plant Biol. (2013)

Model of the regulatory network of ThbZIP1 involved in abiotic stress responses. Stress signals such as ABA are produced in plants when exposed to abiotic stressors, and the expression of MYC is induced by stress signals; then the MYC proteins bind to the E-box motif in the promoter of ThbZIP1 to activate the expression of ThbZIP1. The ThbZIP1 in turn binds to the A-, C- or G-box in the promoter of the genes to alter their expression, resulting that abiotic stress tolerances are improved in plants.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3852707&req=5

Figure 7: Model of the regulatory network of ThbZIP1 involved in abiotic stress responses. Stress signals such as ABA are produced in plants when exposed to abiotic stressors, and the expression of MYC is induced by stress signals; then the MYC proteins bind to the E-box motif in the promoter of ThbZIP1 to activate the expression of ThbZIP1. The ThbZIP1 in turn binds to the A-, C- or G-box in the promoter of the genes to alter their expression, resulting that abiotic stress tolerances are improved in plants.
Mentions: Based on all the experimental data presented here, a model is proposed to explain the ThbZIP1-mediated salt tolerance (FigureĀ 7). Stress signals such as ABA are generated during abiotic stresses, which activate the expression of the transcription factors including MYC; then, the MYC proteins bind to E-box motifs in the ThbZIP1 promoter to induce its expression. Combined with the stress signals, the activated ThbZIP1 in turn binds to the A-, C- or G-box motifs in the promoters of genes to activate their expression, leading to the improvement of abiotic stress tolerance in plants. Therefore, ThbZIP1 is a factor in modulating abiotic stress responses through an ABA-dependent signaling pathway.

Bottom Line: Two MYCs were found to bind to E-box, in the promoter of ThbZIP1 to activate its expression.Compared with wild-type (Col-0) Arabidopsis, transgenic plants expressing ThbZIP1 had an increased tolerance to drought and salt, but had an increased sensitivity to ABA during seed germination and root growth; meanwhile, ROS level, cell death and water loss rate in transgenic plants were significantly reduced.Based on these data, we suggest that ThbZIP1 confers abiotic stress tolerance through activating stress tolerance genes to modulate ROS scavenging ability and other physiological changes involved in stress tolerance, and plays an important role in the ABA-mediated stress response of T. hispida.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, 150040 Harbin, China. ychngwang@yahoo.com.

ABSTRACT

Background: Tamarix spp. are woody halophyte, which are very tolerant to abiotic stresses such as salinity and drought, but little is known about their specific stress response systems. Basic leucine zipper proteins (bZIPs) play important roles in the ability of plants to withstand adverse environmental conditions. However, their exact roles in abiotic stress tolerance are still not fully known. In the current study, we functionally characterized a bZIP gene (ThbZIP1) from Tamarix hispida in response to abiotic stresses.

Results: We addressed the regulatory network of ThbZIP1 in three levels, i.e. its upstream regulators, the cis-acting elements recognized by ThbZIP1, and its downstream target genes. Two MYCs were found to bind to E-box, in the promoter of ThbZIP1 to activate its expression. Expression of ThbZIP1 is induced by ABA, salt, drought, methyl viologen and cold. ThbZIP1 can specifically bind to ACGT elements, with the highest binding affinity to the C-box, followed by the G-box and lastly the A-box. Compared with wild-type (Col-0) Arabidopsis, transgenic plants expressing ThbZIP1 had an increased tolerance to drought and salt, but had an increased sensitivity to ABA during seed germination and root growth; meanwhile, ROS level, cell death and water loss rate in transgenic plants were significantly reduced. Microarray analyses showed that many ROS scavenging genes were up-regulated by ThbZIP1 under salt stress conditions.

Conclusions: Based on these data, we suggest that ThbZIP1 confers abiotic stress tolerance through activating stress tolerance genes to modulate ROS scavenging ability and other physiological changes involved in stress tolerance, and plays an important role in the ABA-mediated stress response of T. hispida.

Show MeSH
Related in: MedlinePlus