Habituated Moringa oleifera callus retains metabolic responsiveness to external plant growth regulators

Application of Plant Growth Regulators Modulates the Profile of Chlorogenic Acids in Cultured Bidens pilosa Cells

“…Partial callus habituation was observed (Figure 1(A3)), where leaf callus grown on MS medium with organics, without added PGRs, still maintained growth. Habituation is an occurrence in which division and growth of cells in culture become independent of added PGRs [20,28]. This was, however, not observed on stem callus maintained on PGR-free media, where reduced callus growth was observed (Figure 1(B3)).…”

“…Even where explant tissue originated from tissue with identical genetic backgrounds, epigenetic changes may still occur in cultured cells where genes responsible for organogenesis are modified (hypoand hypermethylated) [29]. Other factors contributing to loss of totipotency and loss of regenerative abilities include genetic variation and selection pressure, resulting in loss of cells with genetic memory for totipotency [20,29]. The age of plants used also affects the regenerative capacity of ex-plants, such that explants from younger plants have been found to possess better regenerative capacity compared to matured plants [30].…”

“…These were organic acids (gluconic acid, malic acid and citric acid), amino acids (phenylalanine and tryptophan) and two benzoic acids (2,5-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid (as glucogallin)). These metabolites illustrate the link between primary and specialised metabolism with phenylalanine feeding into the phenylpropanoid pathway and being the precursor of the cinnamic and benzoic acids [20,32].…”

“…This is achieved over a two-step process, which includes acquisition of pluripotent cells followed by de novo shoot organogenesis [17]. Generally, a low auxin: cytokinin ratio promotes shoot induction (caulogenesis) from callus cells, while high auxin: cytokinin ratio promotes root formation (rhizogenesis) [14,[18][19][20]. In vitro organogenesis can be described as either indirect or direct.…”

“…The mode of crosstalk between these PGRs varies with plant species and organs being studied [13]. The use of PGRs in cell culture may also elicit production of specialised metabolites that assist cells to adapt to and survive in in vitro growth conditions [20]. Consequently, in this study, the effects of different ratios of PGRs were investigated on B. pilosa callus derived from stems and leaf tissues in order to evaluate how PGR-mediated manipulation of the undifferentiated callus cells would affect the phytochemical profiles of the CGAs previously recorded in B. pilosa tissues [5] and the regenerative potential of these cells.…”