Arabidopsis thaliana DHS2 (AT4G33510) gene promoter is highly wound responsive and requires a part of the first exon sequences for its function
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Wound-responsive promoters are critical for developing the next generation of pest-tolerant transgenics, which would defend host by producing defensive factors at the site of attack. As shikimate pathway genes are known to be induced upon wounding, we evaluated the promoter of Arabidopsis thaliana DHS2 gene, which encodes for the first enzyme of this pathway. Transcription start site mapping showed DHS2 transcript has 89 nucleotide long 5′ UTR and RT-PCR revealed constitutive expression of DHS2 gene. Promoter analysis in transgenic A. thaliana using uidA reporter gene revealed that a part of the first exon of DHS2 is essential for promoter function. Histochemical GUS expression studies showed DHS2 expression in all green parts with the least expression in seedling roots and pollens. DHS2 promoter was found to be highly responsive to wounding giving 2–4 log fold up regulation within 10 min of wounding. Elevated expression level remained stable for 2–3 h and returned to normal after 24 h. In silico search identified wound responsive cis elements within the first exon of the DHS2 gene further underscoring the role of coding sequences in wound response and promoter activity. This is the first report demonstrating that coding sequence of a gene is an essential part of its promoter.
Keywords3-Deoxy-d-arabino-heptulosonate 7-phosphate synthase 2 Shikimate pathway Wound responsive promoter
3-Deoxy-d-arabino-heptulosonate 7-phosphate synthase 2
Protein phosphatase 2C
Transcription start site
We thank NFBSRA, Indian Council of Agricultural Research, New Delhi for financial assistance and National Phytotron Facility, IARI, New Delhi for help in raising Arabidopsis plants under contained conditions.
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Conflict of interest
The authors declare that they have no conflict of interest.