To study the molecular mechanism of salt stress response of peanut small GTP binding protein gene AhRabG3f, a 1 914 bp promoter fragment upstream of the start codon of AhRabG3f gene (3f-P) from peanut was cloned. Subsequently, five truncated fragments (3f-P1-3f-P5) with lengths of 1 729, 1 379, 666, 510 and 179 bp were obtained through deletion at the 5' end, respectively. Plant expression vectors where these six promoter fragments were fused with the gus gene were constructed and transformed into tobacco by Agrobacterium-mediated method, respectively. GUS expression in transgenic tobacco and activity analysis were conducted. The gus gene expression can be detected in the transgenic tobacco harboring each promoter segment, among which the driving activity of the full-length promoter 3f-P was the weakest, while the driving activity of the promoter segment 3f-P3 was the strongest. Upon exposure of the transgenic tobacco to salt stress, the GUS activity driven by 3f-P, 3f-P1, 3f-P2 and 3f-P3 was 3.3, 1.2, 1.9 and 1.2 times compared to that of the transgenic plants without salt treatment. This suggests that the AhRabG3f promoter was salt-inducible and there might be positive regulatory elements between 3f-P and 3f-P3 in response to salt stress. The results of GUS activity driven by promoter fragments after salt treatment showed that elements included MYB and GT1 between 1 930 bp and 1 745 bp. Moreover, a TC-rich repeat between 682 bp and 526 bp might be positive cis-elements responsible for salt stress, and an MYC element between 1 395 bp and 682 bp might be a negative cis-element responsible for salt stress. This study may facilitate using the induced promoter to regulate the salt resistance of peanut.
Arachis/genetics* ; Fabaceae/genetics* ; GTP-Binding Proteins/metabolism* ; Gene Expression Regulation, Plant ; Glucuronidase/metabolism* ; Plant Proteins/metabolism* ; Plants, Genetically Modified/genetics* ; Salt Stress ; Stress, Physiological/genetics* ; Tobacco/genetics*

High salt content in soils severely hampers plant growth and crop yields. Many transcription factors in plants play important roles in responding to various stresses, but their molecular mechanisms remain unclear. WRKY transcription factors are one of the largest families of transcription factors in higher plants that are involved in and influence many aspects of plant growth and development. They play important roles in responding to salt stress. The regulation of gene expression by WRKY proteins is mainly achieved by binding to the DNA's specific cis-regulatory elements, the W-box elements (TTGACC). In recent years, there have been many studies revealing the roles and mechanisms of WRKY family members, from model plant Arabidopsis to agricultural crops. This paper reviews the latest research progress on WRKY transcription factors in response to salt stress and discusses the current challenges and future perspectives of WRKY transcription factor research.
Transcription Factors/metabolism* ; Plant Proteins/metabolism* ; Stress, Physiological/genetics* ; Salt Stress/genetics* ; Crops, Agricultural/genetics* ; Gene Expression Regulation, Plant ; Phylogeny ; Plants, Genetically Modified/genetics*

In order to obtain salt-tolerant calli of Dandelion (Taraxacum officinale Weber), calli were induced from leaf explants of Dandelion on Murashige and Skoog's medium supplemented with 2.0 mg/L 6-benzyladenine and 0.5 mg/L 2,4-dichlorophen oxyacetic acid With 1.5% NaCl as selection pressure, most calli became brown and dead, whereas some new cell clusters appeared at the edge of the brown calli after 2 to 3 weeks. The survived cells were picked out and sub-cultured every 3 weeks onto the fresh selection medium and salt-tolerant calli were finally obtained through 4 continuous selections on the selection medium supplemented with 1.5% NaCl. Salt-tolerant calli increased steadily under a fixed NaCl stress though their relative growth rate decreased with increased NaCl concentration whereas the control calli which were sub-cultured by 4 continus selections on salt free medium ceased to grow under the same condition. This result indicated that the salt-tolerance of the selected calli is improved and this character is stable. Compared with the control, the SDS-PAGE pattern of the salt-tolerant calli had a unique 34 kD protein band. Its 30 kD and 18 kD protein bands were up-regulated. Further more, within the NaCl stress range up to 1.5%, the activities of antioxidant enzymes such as super oxidase dimutase, peroxidase and catalase, and the proline contents of the salt-tolerant calli were higher than those of the control. The results indicated that the selected calli with improved and stable salt tolerance were cell variants. The accumulation of the organic compatible solutes including proteins and the enhanced antioxidant capabilities in the salt tolerant calli are the two ways for them to regulate their osmotic homeostasis and alleviate the secondary reactive oxygen spexies damage respectively.
Adaptation, Physiological ; Cell Culture Techniques ; methods ; Drug Tolerance ; physiology ; Salt-Tolerant Plants ; genetics ; growth & development ; physiology ; Sodium Chloride ; pharmacology ; Stress, Physiological ; Taraxacum ; genetics ; growth & development ; physiology

The preliminary role of calcineurin B-like protein-interacting protein kinases (CIPKs) in stress response is defined but the exact function of OsCIPK10 gene in rice stress response and its expression pattern yet unclear. In this study we explored the possible functions of OsCIPK10 gene by reverse genetics approaches and also revealed its expression pattern by GUS staining. From the preliminary study of this gene we presumed its function to assist plant to resist stress but over-expressed OsCIPK10 rice transgenic lines showed no significant phenotypic differences from the wild type either under high salt or low potassium conditions, however the gene knockdown plants using inverted repeat strategy presented meaningful healthy plants compared to wild type under the stress of salt. Further we checked the expression profile under high salt and low potassium conditions in wild type and found that OsCIPK10 decreases under high salt and increases on low potassium conditions. So we speculate that OsCIPK10 is actually going to function in response to high salt and low potassium stress. We also explored the expression pattern of this gene using Gus staining and found that gene expresses in all plant tissues, the only exception observed was its higher expression in the vascular tissues.
Cloning, Molecular ; Genes, Plant ; Oryza ; enzymology ; genetics ; Plant Proteins ; genetics ; metabolism ; Plants, Genetically Modified ; genetics ; metabolism ; Potassium ; pharmacology ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Salt-Tolerant Plants ; genetics ; Sodium Chloride ; pharmacology ; Stress, Physiological