Ectopic Expression of DREB Transcription Factor, AtDREB1A, Confers Tolerance to Drought in TransgenicSalvia miltiorrhiza

Abstract

Drought decreases crop productivity more than any other type of environmental stress. Transcription factors (TFs) play crucial roles in regulating plant abiotic stress responses. The Arabidopsis thaliana gene DREB1A/CBF3, encoding a stress-inducible TF, was introduced into Salvia miltiorrhiza Ectopic expression of AtDREB1A resulted in increased drought tolerance, and transgenic lines had higher relative water content and Chl content, and exhibited an increased photosynthetic rate when subjected to drought stress. AtDREB1A transgenic plants generally displayed lower malondialdehyde (MDA), but higher superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities under drought stress. In particular, plants with ectopic AtDREB1A expression under the control of the stress-induced RD29A promoter exhibited more tolerance to drought compared with p35S::AtDREB1A transgenic plants, without growth inhibition or phenotypic aberrations. Differential gene expression profiling of wild-type and pRD29A::AtDREB1A transgenic plants following drought stress revealed that the expression levels of various genes associated with the stress response, photosynthesis, signaling, carbohydrate metabolism and protein protection were substantially higher in transgenic plants. In addition, the amount of salvianolic acids and tanshinones was significantly elevated in AtDREB1A transgenic S. miltiorrhiza roots, and most of the genes in the related biosynthetic pathways were up-regulated. Together, these results demonstrated that inducing the expression of a TF can effectively regulate multiple genes in the stress response pathways and significantly improve the resistance of plants to abiotic stresses. Our results also suggest that genetic manipulation of a TF can improve production of valuable secondary metabolites by regulating genes in associated pathways.

Bioinformatic identification and expression analysis of the Malus domestica DREB2 transcription factors in different tissues and abiotic stress

“…Ectopic expression of DREB transcription factor, AtDREB1A, confers tolerance to drought in transgenic Salvia miltiorrhiza, and genetic manipulation of transcription factor can improve production of valuable secondary metabolites by regulating genes in associated pathways. (Wei et al 2016). Apple genome sequencing was completed in 2010, compared with the model plant A. thaliana, apple genome was more complex (Velasco et al 2010).…”

Modulating AtDREB1C Expression Improves Drought Tolerance in Salvia miltiorrhiza

“…The cultures were incubated in a growth chamber at 25 ± 2°C under a 16 h light/8 h dark cycle provided by a cool white fluorescent lamp, providing a PPFD level of 26 μmol m -2 s -1 . The S. miltiorrhiza plants were transformed via the Agrobacterium-mediated leaf-disk method (Wei et al, 2016b), followed by weekly subculturing of the leaf disks. After 35 days, the shoots were cut off of the plants and transferred into selective rooting medium, leading to the production of roots within 2 weeks.…”

“…The cetyltrimethylammonium bromide (CTAB) method was used to isolate genomic DNA from young leaves (Wei et al, 2016b). Positive pCAMBIA3301 transgenic lines were detected using GUS-F/R.…”

“…A modified CTAB method was used to extract total RNA from WT and transgenic lines after drought stress treatment as described previously (Wei et al, 2016b). Semi-quantitative RT-PCR was performed to investigate GUS or AtDREB1C expression in transgenic S. miltiorrhiza lines using specific primers (Supplementary Table S1).…”

“…Overexpression of AtDREB1A, AtDREB1B, and AtDREB1C in Arabidopsis helped confirm that they have matching functional activities; the phenotypes of these lines mimicked the multiple biochemical changes associated with cold acclimation (Gilmour et al, 2004). We previously demonstrated that the drought resistance of both AtDREB1A and AtDREB1B transgenic S. miltiorrhiza plants was significantly improved under severe drought stress (Wei et al, 2016a,b). However, the effects of AtDREB1C overexpression in transgenic S. miltiorrhiza has not previously been examined, and whether overexpressing AtDREB1C can improve the drought tolerance of transgenic plants remains to be determined.…”