A study of some factors affectingAgrobacterium transformation and plant regeneration ofDendranthema grandiflora Tzvelev (syn.Chrysanthemum morifolium Ramat.)

Abstract

In an attempt to develop a system for producing transformed plants from explants of Dendranthema grandiflora, the susceptibility of the cultivar Super White to various wild-type strains of Agrobacterium tumefaciens and A. rhizogenes was investigated. Tumour formation was not a reliable indicator of the ability of a related disarmed strain to mediate transformation. Following inoculation of explants with disarmed Agrobacterium strains, a number of shoots developed on selective media. However, none of these shoots were transformed. By co-cultivating stem internode explants with a mixed inoculum of wild-type and disarmed strains, it was possible to obtain a callus stably transformed with Agrobacterium carrying a disarmed T-DNA. Histological analysis of explants revealed that shoot regeneration initially occurred from the cells of the epidermis and subsequently from the cortex. However, the cells which were susceptible to T-DNA transfer were confined to the vascular tissue.

Highly tumorigenic Agrobacterium tumefaciens strain from crown gall tumors of chrysanthemum

“…In chrysanthemum, cells susceptible to Agrobacterium were competent for regeneration in leaf explants (Van Wordragen et al 1992), but those in stem explants were not competent for regeneration (Lowe et al 1993). The large area transformed by strain CNI5 may favor regeneration of transformed cells.…”

An improved micropropagation system for Chrysanthemum based on Pluronic F-68-supplemented media

“…Alternative approaches, such as the utilisation of tissue culture technologies, coupled with Agrobacterium or biolistic transformation (Lowe et al 1993a), are required to introduce desirable genetic changes. Such transformation methodologies depend on an efficient system for clonal micropropagation of chrysanthemum.…”

Development of anAgrobacterium-mediated transformation system for regenerating garland chrysanthemum (Chrysanthemum coronarium L.)

“…For example, transgenic Dendranthema indicum plants were obtained from leaf explants on a selection medium containing 10 mg L 1 kanamycin (Ledger et al, 1991). However, Lowe et al (1993) reported that only a concentration of 15 mg L 1 kanamycin was effective, whereas. Renou et al (1993) obtained only escapes on media containing 25 mg L -1 kanamycin Plant Biol.…”