Identification of a new 130 bp cis-acting element in the TsVP1 promoter involved in the salt stress response from Thellungiella halophila.
BACKGROUND
Salt stress is one of the major abiotic stresses affecting plant growth and productivity. Vacuolar H+-pyrophosphatase (H+-PPase) genes play an important role in salt stress tolerance in multiple species.


RESULTS
In this study, the promoter from the vacuolar H+-pyrophosphatase from Thellungiella halophila (TsVP1) was cloned and compared with the AVP1 promoter from Arabidopsis thaliana. Sequence analysis indicated that these two promoters had seven similar motifs at similar positions. To determine which tissues the two promoters are active in, transgenic plants were produced with expression of the GUS reporter gene under the control of one of the promoters. In transgenic Arabidopsis with the TsVP1 promoter, the GUS reporter gene had strong activity in almost all tissues except the seeds and the activity was induced in both shoots and roots, especially in the root tips, when treated with salt stress. Such induction was not found in transgenic Arabidopsis with the AVP1 promoter. By analyzing different 5' deletion mutants of the TsVP1 promoter, an 856 bp region (-2200 to -1344) was found to contain enhancer elements that increased gene expression levels. Two AAATGA motifs, which may be the key elements for the anther specific expression profile, in the deleted TsVP1 promoters (PT2 to PT6) were also identified. A 130 bp region (-667 to -538) was finally identified as the key sequence for the salt stress response by analyzing the different mutants both with and without salt stress. GUS transient assay in tobacco leaves suggested the 130 bp region was sufficient for the salt stress response. Bioinformatic analysis also revealed that there may be novel motifs in this region that are the key elements for the salt stress responsive activity of the TsVP1 promoter.


CONCLUSIONS
The TsVP1 promoter had strong activity in almost all tissues except the seeds. In addition, its activity was induced by salt stress in leaves and roots, especially in root tips. A 130 bp region (-667 to -538) was identified as the key region for responding to salt stress.
Sun
Qinghua
Q
School of Life Science, Shandong University, Jinan, China.
Gao
Feng
F
Zhao
Lei
L
Li
Kunpeng
K
Zhang
Juren
J
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D019607:Brassicaceae / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D019295:Computational Biology; D018744:DNA, Plant / Q000235:genetics; D004742:Enhancer Elements, Genetic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017930:Genes, Reporter; D015698:Genomic Library; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D055051:Salt-Tolerant Plants / Q000201:enzymology / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological
D018744:DNA, Plant; D010940:Plant Proteins; D012965:Sodium Chloride; D043564:Inorganic Pyrophosphatase