Genetic engineering to improve β-carotene content in pepper

Abstract

A laboratory study was conducted to develop a broadly applicable in vitro regeneration and transformation methods for increasing β-carotene content in pepper fruits. Therefore, two different pepper genotypes were analyzed with regard to their efficiency for regeneration and genetic transformation in vitro. Cotyledons were used in vitro from young seedlings as target tissue for regeneration and transformation of pepper. Over expression of β-Lcy gene via Agrobacterium-mediated transformation was used. The presence of the transgene was assayed on leaf DNA via PCR and biochemical analysis using HPLC. Results strongly showed that there were significant differences between pepper genotypes. The transgenic pepper plants showed a significant increase in fruit β-carotene content reaching 7 to 10 folds according to the genotype. The fruits from these plants displayed different colour phenotypes, from orange to orange-red. The difference in the fruit colour phenotypes reflects the beta-carotene ratio, which ranges from 4.5 mg/100g dw in the wild plants to 45.0 in the transgenic plants of genotype Balady during maturity stage. Concerning to the genotype Topepo rosso, the β-carotene content was increased from 5.2 mg/100g dw in the wild plants to 36.39 mg/100g dw in the transgenic plants during mature stage.

Genetic Regulation, Environmental Cues, and Extraction Methods for Higher Yield of Secondary Metabolites in Capsicum

“…β-LCY gene was overexpressed in two pepper genotypes via Agrobacterium-mediated transformation that resulted in a 10-fold increase [from 4.5 to 45.0 mg 100 g −1 dry weight (DW)] in the β-carotene levels in the Balady genotype fruits and ∼7-fold increase (from 5.2 to 36.39 mg 100 g −1 DW) in the Topepo rosso fruits, respectively. 79 A successful attempt of producing the red carotenoid capsanthin in microorganisms was done by overexpressing the CCS gene from C. annuum in Escherichia coli alongside regulating seven other upstream pathway genes. 80 The capsaicin synthase protein purified from a recombinant E. coli host was found to be a monomeric protein of 51 kDa that catalyzed the formation of an amide bond specifically between vanilloylamine and trans-8-methyl-6-nonenoyl-CoA independent of any cofactors.…”

“…The successful transfer of the whole metabolic pathway in a microbial host would enable massive production of the useful bioactive compounds using basic raw material like amino acids. β-LCY gene was overexpressed in two pepper genotypes via Agrobacterium -mediated transformation that resulted in a 10-fold increase [from 4.5 to 45.0 mg 100 g –1 dry weight (DW)] in the β-carotene levels in the Balady genotype fruits and ∼7-fold increase (from 5.2 to 36.39 mg 100 g –1 DW) in the Topepo rosso fruits, respectively . A successful attempt of producing the red carotenoid capsanthin in microorganisms was done by overexpressing the CCS gene from C. annuum in Escherichia coli alongside regulating seven other upstream pathway genes .…”