Soybean plants are sensitive to the effects of abiotic stress and belong to the group of crops that are less drought and salt tolerant. The identification of genes involved in mechanisms targeted to cope with water shortage is an essential and indispensable task for improving the drought and salt tolerance of soybean. One of the approaches for obtaining lines with increased tolerance is genetic modification. The dehydration-responsive element binding proteins (DREBs), belonging to the AP2 family, are trans-active transcription factors that bind to the cis-sequences of the promoter for activating the expression of the target genes that mediate drought and salt tolerant responses. In this study, the GmDREB6 transgene was introduced into DT84 cultivar soybean plants, using Agrobacterium-mediated transformation. The efficacy of GmDREB6 overexpression in enhancing the transcriptional level of GmP5CS and proline accumulation in genetically modified (GM) soybean plants was also assayed. The results demonstrated that ten GM soybean plants (T0 generation) were successfully generated from the transformed explants after selecting with kanamycin. Among these plantlets, the presence of the GmDREB6 transgene was confirmed in nine plants by Polymerase Chain Reaction (PCR), and eight plants showed positive results in Southern blot. In the T1 generation, four GM lines, labelled T1-2, T1-4, T1-7, and T1-10, expressed the recombinant GmDREB6 protein. In the T2 generation, the transcriptional levels of the GmP5CS gene were higher in the GM lines than in the non-transgenic plants, under normal conditions and also under conditions of salt stress and drought, ranging from 1.36 to 2.01 folds and 1.58 to 3.16 folds that of the non-transgenic plants, respectively. The proline content was higher in the four GM soybean lines, T2-2, T2-4, T2-7, and T2-10 than in the non-transgenic plants, ranging from 0.82 μmol/g to 4.03 μmol/g. The proline content was the highest in the GM T2-7 line (7.77 μmol/g). In GM soybean lines, T2-2, T2-4, T2-7, and T2-10 proline content increased after plants were subjected to salt stress for seven days, in comparison to that under normal conditions, and ranged from 247.83% to 300%, while that of the non-GM plants was 238.22%. These results suggested that GmDREB6 could act as a potential candidate for genetic engineering for improving tolerance to salt stresses.

Adrinandra megaphylla Hu is a medicinal plant belonging to the Adrinandra genus, which is well-known for its potential health benefits due to its bioactive compounds. This study aimed to assemble and annotate the chloroplast genome of A. megaphylla as well as compare it with previously published cp genomes within the Adrinandra genus. The chloroplast genome was reconstructed using de novo and reference-based assembly of paired-end reads generated by long-read sequencing of total genomic DNA. The size of the chloroplast genome was 156,298 bp, comprised a large single-copy (LSC) region of 85,688 bp, a small single-copy (SSC) region of 18,424 bp, and a pair of inverted repeats (IRa and IRb) of 26,093 bp each; and a total of 51 SSRs and 48 repeat structures were detected. The chloroplast genome includes a total of 131 functional genes, containing 86 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The A. megaphylla chloroplast genome indicated that gene content and structure are highly conserved. The phylogenetic reconstruction using complete cp sequences, matK and trnL genes from Pentaphylacaceae species exhibited a genetic relationship. Among them, matK sequence is a better candidate for phylogenetic resolution. This study is the first report for the chloroplast genome of the A. megaphylla.

The dehydration responsive element binding (DREB) is a plant protein subfamily expressed when soybean plants face abiotic stresses. These DREB proteins are also considered to activate the transcription of drought-resistant genes. In this study, we present the determined results of relationships between overexpression of Glycine max DREB2 (GmDREB2) with the transcription level of Glycine max pyrroline-5-carboxylate synthetase (GmP5CS) gene, proline accumulation and drought tolerant ability transgenic soybean plants as the basis for selection of transgenic lines with high drought tolerance. GmDREB2 was inserted into a plant transgenic vector and the 35S-GmDREB2-cmyc construct was transferred into the soybean plants by Agrobacterium-mediated transformation. Recombinant GmDREB2 protein with a molecular weight of approximately 20 kDa was expressed in four transgenic soybean lines in the T1 generation. The GmP5CS gene was shown to have significantly (P<0.05) increased expression in the T2 transgenic soybean lines and higher than compared to non-transgenic plants with considering both in well watered condition and stressed conditions were from 1.06 to 1.31-fold and 1.37 to 1.95-fold, respectively. The proline content of four transgenic soybean lines increased 155.81% to 187.42 % after five days in drought-stress conditions and increased from 180.52 % to 233.74 % after nine days under drought-stress conditions (P<0.05). Therefore, the overexpression of GmDREB2 resulted in increasing transcription level of P5CS gene, proline accumulation and drought-stress tolerance of the transgenic soybean plants. The GmDREB2 transformation into soybean plants was confirmed by the results of genetically modified lines in the T2 generation (T2-1, T2-6, T2-7, and T2-8) with higher drought tolerant ability than those of non-transgenic plants.

Soil is contaminated with salinity, which inhibits plant growth and development and reduces crop yields. The DREB (dehydration responsive element binding protein) gene responds to salt stresses through enhanced transcriptional expression and activation of genes involved in plant salinity resistance. In this study, we present the results of the analysis of the expression of the GmDREB6 transgene, a gene that encodes the soybean DREB6 transcription factor, regulating the transcription of the NtP5CS and NtCLC genes in transgenic tobacco under salt stress conditions. The transcription of GmDREB6, NtP5CS, and NtCLC in transgenic tobacco lines was confirmed by qRT-PCR. Under salt stress conditions, the GmDREB6 gene transcription levels in the transgenic tobacco lines L1 and L9 had increased from 2.40- to 3.22- fold compared with the condition without salinity treatment. Two transgenic lines, L1 and L9, had transcription levels of the P5CS gene that had increased from 1.24- to 3.60- fold compared with WT plants. For the NtCLC gene, under salt stress conditions, the transgenic lines had transcription levels that had increased by 3.65–4.54 (fold) compared with WT plants (P < 0.05). The L1-transgenic tobacco line showed simultaneous expression of both the GmDREB6 transgene and two intrinsic genes, the NtP5CS and NtCLC genes. This study demonstrated that expression of the GmDREB6 gene from soybean increases the transcription levels of the NtP5CS and NtCLC genes in transgenic tobacco plants under salt stress conditions. The analysis results have suggested that the GmDREB6 gene is a potential candidate for improving the salt tolerance of plants, opening up research and development opportunities for salt stress-tolerant crops to respond to climate change and the rise in sea levels.