In vitro selection and regeneration of chrysanthemum (Dendranthema grandiflorum Tzelev) plants resistant to culture filtrate of Septoria obesa Syd

Abstract

Callus cultures derived from leaf segments of chrysanthemum cultivar 'Snow Ball' which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About 30% of the plants regenerated from the resistant calluses and 70-80% of the plants raised from cuttings had acquired considerable resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates.

Response of carrot protoplasts and protoplast-derived aggregates to selection using a fungal culture filtrate of Alternaria radicina

“…Somaclonal variation generated in such conditions may be identified on morphological, physiological, molecular, or cytological levels (reviewed by Bairu et al 2011). In many cases, plants regenerated under biotic stress did not show phenotypic variation and remained morphologically identical to the donor plants (Thakur et al 2002;Ganesan and Jayabalan 2006;Kumar et al 2008;Savita et al 2011), or the frequency of changed plants was low, i.e., 2 % in FCF-challenged embryogenic callus cultures of sugarcane (Mahlanza et al 2013). Our results are consistent with these observations.…”

“…Culture filtrates are known to contain a number of phytotoxic compounds, which may play an important role in pathogenicity. Explants from susceptible and tolerant materials cultured in vitro vary in response to these toxic metabolites, thus, making such phytotoxins effective selective agents for in vitro selection strategies towards disease tolerance (Binarova et al 1990;Remotti et al 1997;Kumar et al 2008;Flores et al 2012). Radicinin, radicinol, and epi-radicinol are the main phytotoxins involved in the pathogenicity of A. radicina against carrots (Solfrizzo et al 2004).…”

“…This was preferred for explants consisting of many cell layers such as plant organs, callus tissue, or suspension cultures. Successful selection with stepwise treatment was reported in the callus tissue of carnation (Thakur et al 2002), chrysanthemum (Kumar et al 2008) and citrus (Savita et al 2011). However, prolonged exposure to toxins can result in reduced regeneration ability and occurrence of undesired mutations.…”

“…These selective agents elicit typical reactions such as the production and accumulation of antimicrobial phytoalexins in the cells (Š vábová and Lebeda 2005). A high correlation between in vitro and in vivo resistance to pathogenic fungi was reported (Kumar et al 2008;Savita et al 2011), however, resistance to pathotoxins at the cellular level may not always lead to whole plant resistance to the pathogen (Sharma et al 2010).…”

Microscopic callus selection of sengon tree (Falcataria moluccana) putative tolerant to Uromycladium falcatarium

“…The difference in the cell reaction on the index value parameter of the biotic pathogen filtrate indicates the presence of an enzymatic defence process of the sengon callus cell. Kumar et al [17] reported that the pathogen filtrate induced oxidative pressure during the in vitro selection. During the agent selection treatment, the cells reproduced a radical superoxide which was immensely toxic to protect the cells from the pathogen filtrate pressure.…”