Thidiazuron induced somatic embryogenesis and plant regeneration in Capsicum annuum

Abstract

An efficient protocol of direct somatic embryogenesis (without involving intermediate callus) has been developed from stem segments and shoot tips of Capsicum annuum L. Explants were cultured on Murashige and Skoog (MS) medium supplemented with thidiazuron (TDZ). Among the various concentration of TDZ tested, 0.5 µM was proved to be best for induction of somatic embryos. Induction, maturation and germination were achieved on the same medium. The shoots developed from somatic embryos were transferred for rooting to MS medium supplemented with indole-3-butyric acid (IBA). All the regenerated plants with 85 % survival rate were normal with respect to morphology and growth characteristics.Additional key words: chilli pepper, direct somatic embryogenesis, growth regulators, in vitro. ⎯⎯⎯⎯Capsicum annuum L. is an economically important crop plant and two main consumption types of pepper spice and vegetable are prevalent throughout the world. In order to facilitate development of plant biotechnology based cultivar improvement for this species, considerable effort has been devoted in developing and optimizing efficient in vitro regeneration protocols. Plant regeneration via organogenesis and somatic embryogenesis from diverse explants using different concentration and combinations of auxin and cytokinins has been described in pepper (Harini and Sita 1993, Fari and Andrasfalvy 1994, Steinitz et al. 1999, Ochoa Alejo and Ramirez-Malagon 2001. In spite of these reports, reproducible methods for routine propagation are not available and existing methods are not satisfactory.Somatic embryogenesis, the production of bipolar structures from somatic cells is of considerable theoretical and practical importance because it can be used to combine efficient cloning with genetic modification (Sharp et al. 1980). In vitro somatic embryos can develop either from callus or directly from the explant without any intermediate callus stage. Since plant regeneration from callus cultures is often associated with genetic and cytological variations (Larkin and Scowcraft 1981) which are not always desirable, direct somatic embryogenesis has better applicability in the improvement of crops.Thidiazuron (TDZ), a substituted phenyl urea (N-phenyl-1,2,3-thidiazol-5-yl urea) is a potent plant growth regulator which exhibit cytokinin like activity in various culture systems. TDZ was successfully applied to induce organogenesis from different explants such as wounded seedlings, intact seedlings, leaf, cotyledonary nodes and shoot tip of pepper (Szasz et al. 1995, Hyde and Phillips 1996, Dabauza and Pena 2001, Venkataiah et al. 2003) but none of these reports have used TDZ for the induction of somatic embryogenesis.In this communication, we reported a high frequency regeneration system in chilli pepper through direct somatic embryogenesis from stem segment and shoot tip explants using TDZ, without involving callus phase.Seeds of Capsicum annuum L. cv. Pusa Jwala were presoaked overnight and washed under running tap water for 30 min to remove adherent pa...

Direct Somatic Embryogenesis and Organogenesis from Axillary Meristem in Taro (<i>Colocasia esculenta</i> var. <i>esculenta</i>)

“…The high efficacy of TDZ for inducing somatic embryogenesis has already been demonstrated in several monocot and dicot plants [6,7,9,13,21,22]. In many cases, TDZ induced embryogenesis was reported to be of higher efficiency and frequency as compared to other cytokinins or the combination treatments of auxins and cytokinins [3,21,26,30].…”

Somatic Embryogenesis in Capsicum spp.

“…However, the regenerated somatic embryos exhibited morphological anomalies (absence of cotyledons, a single deformed cotyledon, a cup-shaped cotyledon or the absence of a shoot). Khan et al (2006) described the direct somatic embryo formation on stem and shoot tip explants of C. annuum cv. Pusa Jwala cultured on MS medium supplemented with 0.5 μM TDZ.…”

Effect of Thidiazuron used as an Elicitor in the Production of Capsaicin Ontotal Protein and Phenolic Amounts, Antioxidant Enzyme Activities of Pepper Plants

“…Two main consumption types of pepper, spice and vegetable,that are prevalent throughout the world [1]. Capsicum species are well-known because of many medicinal properties.…”

“…Therefore, Capsicum free and immobilized cell cultures can be an important way to obtain capsaicin [10,14]. Thidiazuron (TDZ), a substituted phenlyurea (N-phenyl-1,2,3-thidiazol-5-yl urea), is a potent plant growth regulator that exhibits auxin-and cytokinin-like activity in various culture systems [1,15]. A number of physiological and biochemical events in cells are induced or enhanced by TDZ [15].…”