Technological milestones from plant science to agricultural biotechnology

Viral hemorrhagic septicemia virus glycoprotein production in tobacco

Viral hemorrhagic septicemia virus (VHSV) causes mortality in numerous marine and freshwater fish species resulting in heavy losses in fish farming. The glycoprotein gene of VHSV was fused with the cholera toxin B subunit (CTB) and expressed transiently in leaf tissues of Nicotiana benthamiana via the agroinfiltration method. The glycoprotein gene was divided into two parts to improve assembly of CTB fusion proteins (CTB-VHSV99-235 and CTB-VHSV258-417). Production of CTB fusion proteins was confirmed in the agroinfiltrated leaf tissue by western blot analysis. The plant-produced CTB fusion proteins showed biological activity to GM1-ganglioside, a receptor for biologically active CTB, on GM1-ELISA. The expression level of the CTB-VHSV fusion proteins was 0.86% (CTB-VHSV99-235) and 0.93% (CTB-VHSV258-417) of total proteins in agroinfiltrated leaf tissue, as determined by GM1-ELISA. These results suggest that Agrobacterium-mediated transient expression of CTB fusion antigens of VHSV is a rapid and convenient method and demonstrate the feasibility of using agroinfiltrated plant leaf tissues expressing CTB-fusion antigens as a plant-based vaccine to prevent VHSV infection.

The expression of classical swine fever virus structural protein E2 gene in tobacco chloroplasts for applying chloroplasts as bioreactors

It has been reported that genes encoding antigens of bacterial and viral pathogens can be expressed in plants and are shown to induce protection antibodies. The structural protein E2 of classical swine fever virus (CSFV), which has been shown to carry critical epitopes, has been expressed in different systems. Here, we report the expression of CFSV E2 gene in tobacco chloroplasts. Mice immunized with leaf extracts elicited specific antibodies. This indicated that the expressed E2 proteins had a certain degree of immunogenicity. To our knowledge, this is the first report showing induction of protective antibody in response to classical swine fever virus (CSFV) by immunization with antigen protein E2 expressed in tobacco chloroplasts, which will open a new way to protection from CSFV by plant chloroplasts as bioreactors.

Some advances in plant stress physiology and their implications in the systems biology era

The study for biointerfaces at different scales in the past years has pricked up the march of biological sciences, in which biomembrane concept and its characteristics, receptor proteins, ion channel proteins, LEA proteins, calcium and newly recognized second messengers, ROS, MAPKs and their related sensors and new genes in osmoregulation, signal transduction, and other aspects have been understood fully, widening area of understanding the extensive interactions from biosystem and biointerfaces. The related discipline, plant stress physiology, especially, crop stress physiology has gained much attention world widely, the important reason of which is from the reducing quality of global ecoenvironment and decreasing food supply. This short review will place a stress on the recent progresses in plant stress physiology, combined with the new results from our State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau.

Stable expression of foot-and-mouth disease virus protein VP1 fused with cholera toxin B subunit in the potato (Solanum tuberosum)

The expression vector, pBI121CTBVP1, containing the fusion of the foot and mouth disease virus (FMDV) VP1 gene and the cholera toxin B subunit (CTB) gene was constructed by fused PCR and transferred into potato (Solanum tuberosum L.) by Agrobacterium-mediated transformation. Transformed plants were obtained by selecting on kanamycin-resistant medium strictly and regenerated. The transgenic plantlets were identified by PCR, Southern-blot and the production of fused protein was confirmed and quantified by Western-blot and ELISA assays. The results showed that the fused genes were expressed stablely under the control of specific-tuber patatin promoter. The expressed fused proteins have a certain degree of immunogenicity.

Recombination and expression of classical swine fever virus (CSFV) structural protein E2 gene in Chlamydomonas reinhardtii chroloplasts

The expression of classical swine fever virus (CSFV) structural protein E2 in different vectors, which has been shown to carry critical epitopes, has been established. Here, we reported a Chlamydomonas reinhardtii chloroplast expression vector, P64E2, containing classical swine fever virus structural protein E2 gene, which was constructed and transferred to C. reinhardtii by biolistic bombardment method. The transformants were identified by PCR, Southern blotting, Western blotting after selecting on resistant media. ELISA quantification assay showed that the expressed E2 protein accumulated up to 1.5-2% of the total soluble protein. The results of the study on the immunological activity indicated that the protein E2 expressed in C. reinhardtii chloroplasts could elicit animal bodies to produce antibodies against protein E2.

Plant biotechnology: ecological case studies on herbicide resistance

The emerging field of molecular ecology aims to improve the ecological predictability of transgenic crop plants. The most widely cultivated lines are Roundup-Ready plants, which are genetically modified to be resistant to the broad-spectrum herbicide glyphosate. Recent publications demonstrate two ecological effects that were not anticipated: the widespread emergence of glyphosate-resistant weed biotypes and the formation of a metabolic herbicidal residue. Both effects appear to be due to the increased use of glyphosate rather than the genetic modification in the transgenic crop plant. With one prominent exception, opinions collected from the literature point towards a certain degree of resistance mismanagement and an inadequate testing of the ecological effects of extensive glyphosate use.