Expression of a novel bi-directional Brassica napus promoter in soybean

Abstract

The expression profile of a natural bi-directional promoter, derived from the Brassica napus EPSPS-A gene, was studied in transgenic soybean (Glycine max C.V. Maverick) lines. Two constructs, pDAB100331 and pDAB100333, were assembled to test the bi-directionality of the promoter. Two reporter genes, gfp and gusA, were employed and they were interchangeably placed in both constructs, one on each end of the promoter such that both proteins expressed divergently in each construct. In the T generation, GUS expression was more uniform throughout the leaf of pDAB100333 transgenic plants, where the gusA gene was expressed from the downstream or EPSPS-A end of the bi-directional promoter. Comparatively, GUS expression was more localized in the midrib and veins of the leaf of pDAB100331 transgenic plants, where the gusA gene was expressed from the upstream end of the bi-directional promoter. These observations indicated a unique expression pattern from each end of the promoter and consistently higher expression in genes expressed from the downstream end (e.g., EPSPS-A end) of the promoter in the tissues examined. The GFP expression pattern followed that of GUS when placed in the same position relative to the promoter. In the T generation, transcript analysis also showed higher expression of both gusA and gfp when those genes were located at the downstream end of the promoter. Accordingly, the pDAB100331 events exhibited a higher gfp/gusA transcript ratio, while pDAB100333 events produced a higher gusA/gfp transcript ratio consistent with the observations in T plants. These results demonstrated that the EPSPS-A gene bidirectional promoter can be effectively utilized to drive expression of two transgenes for the desired traits.

Isolation and Functional Characterization of a Green-Tissue Promoter in Japonica Rice (Oryza sativa subsp. Japonica)

“…The reverse promoter mainly means that its forward promoter cannot drive the expression of foreign genes. However, a few studies are reported on plant reverse promoters, most of the studies are focused on bi-directional promoters, such as BEAP [ 23 ], Cab1/2 [ 24 ] and BDDP [ 25 ]. Rice is one of the most important food crops in the world [ 26 , 27 ].…”

Proteomic Profiling of Fast Neutron-Induced Soybean Mutant Unveiled Pathways Associated with Increased Seed Protein Content

“…Soybean (Glycine max­[L.] Merr) seeds are very rich in protein (∼40%) and oil (∼20%) content. There is a renewed interest in research to increase the percent of seed proteins in soybean, especially for the food industries that depend on soybean protein as a major source of their raw materials. − Genetic research with soybean has been augmented by the submission of the reference genome sequence in 2010, which greatly enhanced the scope of exploration of niches to improve soybean seed quality …”

A modified pod specific promoter for high level heterologous expression of genes in legumes

“…In the present study the primary objective is to develop gene constructs for high level tissue specific expression of genes in pods of chickpea. Contextually, use of chimeric promoters or Bidirectional Duplex promoters (BDDP) in combination with strong terminators has been shown to drastically enhance transcriptional efficiency of genes (Chen et al, 2018, Chennareddy et al, 2017, Li et al, 2004. However, use of tissue specific promoters as BDDP in combination with transcriptional and translational enhancers has not been reported yet.…”