Confirmation of “pre-plasmolysis mediated ex-osmosis hypothesis” to obtain shoot bud morphogenesis in Catharanthus roseus

Abstract

The antineoplastic herb, Catharanthus roseus is a classified high-value low-volume medicinal herb which is in global attention of scientific research for modulation of its monoterpenoid indole alkaloids (MIA) pathway through genetic engineering. These secondary metabolites are generally stored in specific types of structures/compartments due to their cytotoxic nature and designated roles in plant defense response. However, their presence can hinder the genetic engineering process used to develop transgenic plants through de novo morphogenesis and regeneration of plants from cultured cells/tissues and hence, it always remained a critical impediment in transgenic research in C. roseus. The pre-plasmolysis treatment of leaf explants can help to tackle the recalcitrant nature of leaf explant and can support the direct regeneration response by ex-osmosis that minimizes the concentration of alkaloids. Therefore, this study was performed to chase the effect of osmotic conditions on recalcitrant leaves of C. roseus engaged in vitro plant regeneration and hypothesis of alkaloids ex-osmosis is confirmed by HPLC analysis.

Ethyl Methane Sulfonate and Sodium Azide-Mediated Chemical and X-ray-Mediated Physical Mutagenesis Positively Regulate Peroxidase 1 Gene Activity and Biosynthesis of Antineoplastic Vinblastine in Catharanthus roseus

“…In jasmonic acid elicitation studies on C. roseus , Wei et al [ 34 ] inferred that MIA pathway genes expression was directly proportional to the associated cytochrome P450 enzyme ( CPR ) expression. Additionally, most MIA pathway genes are associated with mitochondrial and chloroplast membranes [ 1 , 10 ]. In addition, the cytochrome P450 monooxygenase system is associated with the photosynthetic membrane and mitochondrial membrane, regulating the photosynthesis and electron transport chain through the light absorption capacity of chlorophyll pigments and resulting light-inducible nature of cytochrome enzymes.…”

“…For commercial production, semi-synthetic derivatives of vinblastine and vincristine are produced via monomeric precursors, catharanthine, and vindoline [ 8 ]. The present decade has witnessed extensive research into C. roseus , with substantial efforts being made to decode/delineate the missing links (steps) of the pathway architecture in terms of enzymes, intermediates, and key pathway genes [ 9 ], while metabolic modulations through hyper- or down-regulation of known MIA pathway genes are a primary focus of C. roseus biotechnological interventions [ 10 ]. Although great efforts are being made towards the improvement of the yield of plant alkaloids, mutagenesis for crop breeding/improvement via physical/chemical mutagens remains a less-explored area.…”