Objective This study aims to provide reference for revealing the role of steroid 22-alpha hydroxylase in moso bamboo (PeDWF4) in the response to abiotic stresses, based on the analysis of its gene structural characteristics and expression patterns.
Method The method of homologous sequence comparison was used to isolate the homologous gene of DWF4 in moso bamboo with the information in BambooGDB. Bioinformatic method was used to analyze the gene structure, the basic physical and chemical characteristics, the conservative domains in the protein encoded by the gene, and the evolutionary relationships, etc. Besides, RT-PCR was applied for the gene expression analysis in different bamboo tissues and real-time fluorescent quantitative PCR (qRT-PCR) was conducted to find the expression patterns of the gene in leaf blades under the stresses of high salt, drought, low temperature and high light, respectively.
Result PeDWF4, a homologous gene of DWF4, was isolated from moso bamboo, whose open reading frame is 1 503 bp, and the corresponding genome sequence is 6 149 bp containing 8 exons and 7 introns. The introns completely conformed to the principle of GT-AG splicing. PeDWF4 encoded an alkaline protein with 500 aa, belonging to the single oxygenases of cytochrome P450 family. Tissue specific expression analysis showed that PeDWF4 was detected in all tissues of bamboo roots, stems, fully expanded leaf blades, not fully expanded leaf blades, leaf sheaths and shoots with different levels, among which the highest one was in leaf blades, followed by roots, while those in stems, sheaths and shoots were relatively lower. In accordance with the transcriptome data, PeDWF4 had the highest expression level in leaf blades. Both under NaCl (400 mmol·L-1) and drought stresses, the expression of PeDWF4 in leaf blade showed a trend of induction and then suppression. Under NaCl stress, it was upregulated to 3.5 times of the control after 2 hours, then decreased gradually with the prolonged processing and reached to nearly only 20% of the control after 6 hours. That under drought stress was upregulated to 2 times of the control after 1 hour, and decreased to 60% of the control after 8 hours. The expression of PeDWF4 was induced by both high light (1 200 μmol·m-2·s-1) and low temperature (4℃) stresses. Under high light stress, it was upregulated to 4.5 times of the control after 2 hours, then decreased gradually with the prolonged processing and reached to 2 times of the control after 8 hours. That under low temperature stress was upregulated to 3 times of the control after 1 hour, and then decreased gradually and reached to 2 times of the control after 8 hours.
Conclusion PeDWF4, a DWF4 homologous gene is isolated from moso bamboo, which belongs to the single oxygenase gene of cytochrome P450 family. PeDWF4 is constitutively expressed in moso bamboo. The expression changes indicate that PeDWF4 is involved in response to NaCl, drought, low temperature and high light stresses, which might be helpful to improve the ability of moso bamboo to withstand abiotic stresses.
DownLoad: