Characterization of the promoter region of the glycerol-3-phosphate-O-acyltransferase gene in Lilium pensylvanicum

Authors: LIJING CHEN, LI ZHANG, WEIKANG QI, MUHAMMAD IRFAN, JING-WEI LIN, HUI MA, ZHI-FU GUO, MING ZHONG, TIAN-LAI LI

Abstract: Cold environmental conditions influence the growth and development of plants, causing crop reduction or even plant death. Under stress conditions, cold-inducible promoters regulate cold-related gene expression as a molecular switch. Recent studies have shown that the chloroplast-expressed GPAT gene plays an important role in determining cold sensitivity. However, the mechanism of the transcriptional regulation of GPAT is ambiguous. The 5'-flanking region of GPAT with length of 1494 bp was successfully obtained by chromosome walking from Lilium pensylvanicum. The cis-elements of GPAT promoters were predicted and analyzed by a plant cis-acting regulatory DNA element database. There exist core promoter regions including TATA-box and CAAT-box and transcription regulation regions, which involve some regulatory elements such as I-box, W-box, MYB, MYC, and DREB. Full-length and four 5'-deletion fragments linked with GUS vectors were constructed and transformed into Nicotiana tabacum by Agrobacterium-mediated transformation. Transient transformation and histochemical staining of leaves indicated that the activity of the GPAT promoter was strong and induced by low-temperature stress. The deletion of a -294 bp region suggested that the DRE-motif was functionally an essential element for cold induction, and the deletion of -1494 bp and -1194 bp regions suggested that negative regulation exists in the promoter. Our results show that the GPAT gene promoter is a key regulator under cold stress and we think that this study will have significant impact on lily molecular breeding and improving the resistance of plants.

Keywords: GPAT, promoter, chromosome walking, cis-elements, 5'-deletion fragments, histochemical staining

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