Regulation of somatic embryogenesis in long‐term callus cultures of sugarcane (Saccharum officinarum L.)

Abstract

SUMMARYEmbryogenically competent callus was induced from in vitro grown Saccharum officinarum L. (NCo 310) plantlets by plating young leaf segments on MS basal medium supplemented with 30 /iM dicamba for 21 d in darkness, and subsequently transferring to a medium (EFDM) on which embryos could form and develop. Embryogenic response was improved if the EFDM was supplemented with 1 or 5 fiM. dicamba, casein hydrolysate (1 g 1"'), and 6 % maltose or 6-9 % corn syrup. Calli maintained their embryogenic competence for up to 16 months under these conditions, and with alternate weekly subcultures on to fresh media containing 20 fiM and 30 fiM dicamba in the dark, embryogenic callus proliferation could be further increased. Additional improvements in embryogenic competence were optimized to over 40 months when primary callus was alternately precultured at weekly intervals either witb 10"^ M ABA or S % sorbitol and then transferred to a medium containing 20 or 30 /iM dicamba during maintenance. In general, medium plant growth regulator and nutritional cues, especially dicamba concentration, maltose/corn syrup levels and ABA/sorbito\ preconditioning, were observed to influence critically both embryogenic callus proliferation and the frequency of somatic embryogenesis. The data are discussed within the context that these treatments can be successfully manipulated to enhance long-term embryogenic competence and high-frequency somatic embryogenesis in sugarcane.Key words: Saccharum officinarum (sugarcane), abscisic acid, corn syrup, dicamba, embryogenic competence, maltose.some as yet unknown physiological factors, long-INTRODUCTION term retention of embryogenic competence in most There are currently many reports of somatic embr>'o-grass cell and tissue culture systems has proved to be genesis in callus cultures of the major species of quite difficult (VasU, 1987). Gramineae. In these crops the phenomenon of As part of our continuing investigation of somatic somatic embryogenesis holds useful promise for embr>'o differentiation in Saccharum officinarum L., breeding purposes, particularly with respect to cell we report here on a series of experiments, the fusion, the stable introduction of foreign genetic purpose of which was to evaluate the influence of information, and tolerance to salt and herbicides, various medium components and culture conditions. Additionally, mass in vitro production of somatic which could be manipulated to enhance long-term embryos in bioreactors and the subsequent pro-retention of embryogenic competence and highduction of synthetic seeds with characteristically frequency initiation and development of somatic superior (or desirable) qualities to in situ seeds, can embryos in this species, only be achieved if efficient culture conditions are fully developed for long-term, high-frequency ^^.^ERIALS AND METHODS optimization of high-quality somatic embryos with ^^^^^^ induction and culture conditions reliable regenerative competence. Thus far, however, because of the arbitrary nature of media recipes and ...

Improving in vitro leaf disk regeneration system of sugarcane (Saccharum officinarum L.) with concurrent shoot/root induction from somatic embryos

“…The regeneration potential of SPF-234, HSF-242, and CPF-246 from the innermost leaf roll explants was 16.2%, 9.5%, and 10.2% higher, respectively, than that of shoot tip explants. It was observed from this experiment that leaf roll was the best explant, as supported by many other studies (Brisibe et al, 1994;Chengalrayan and Gallo-Meagher, 2011;Malabadi et al, 2011), and 2.5 mg/L BAP was the best level for in vitro regeneration of the cultivars studied.…”

Morfogênese in vitro e susceptibilidade de calos de variedades nacionais de cana-de-açúcar (Saccharum officinarum L.) a agentes seletivos utilizados em sistemas de transformação genética

“…Srinivasan & Vasil (1986) e Chen et al (1988) descreveram a regeneração de plantas a partir de protoplastos, embora seus resul-tados não tenham sido reproduzidos por outros pesquisadores (Liu 1994). A indução de calos embriogênicos já foi obtida em explantes de cana-de-açúcar inoculados em meio suplementado com diversos tipos de auxina (Ho & Vasil 1983, Fitch & Moore 1990, Brisibe et al 1994. Taylor et al (1992) descreveram a indução de calos organogênicos e embriogênicos em 18 cultivares, bem como a obtenção de culturas de células em suspensão.…”

Polyamine Accumulation and Near Loss of Morphogenesis in Long-Term Callus Cultures of Rice (Restoration of Plant Regeneration by Manipulation of Cellular Polyamine Levels)

“…Although some reports indicate plant regeneration from long-term cultures of rice (Kavikishor, 1987;Ozawa and Komamine, 1989;Binh et al, 1992) and in other cereals (Vasil et al, 1984;Vasil, 1987;Brisibie et al, 1994), the development of simple, uniform, and efficient plant regeneration from long-term cultures still remains a difficult proposition.…”

“…Rice (Oryza sativa L.), along with other cereals, shares the problem of loss of regeneration ability within a few subcultures (Vasil et al, 1984;Kavikishor and Reddy, 1986;Vasil, 1987;Binh and Heszky, 1990;Asano et al, 1994;Brisibie et al, 1994). Therefore, high-frequency, long-term plant regeneration from cereal tissue cultures should be optimized for genetic transformation.…”