In vitro analysis of susceptibility to Agrobacterium rhizogenes in 65 species of Mexican cacti

Abstract

Susceptibility of Mexican cacti to Agrobacterium rhizogenes was evaluated in 65 species of 22 genera. Stem discs taken from in vitro cultured plants were inoculated with Agrobacterium rhizogenes A4 agropine-type strain that contains the wild RiA4 plasmid and the binary vector pESC4 with the nptII and gus genes. Hairy roots were produced directly from wounds, or starting from calli generated on the wounded surface, in 34 of the evaluated species. The frequency of hairy roots formation, the number of roots per explant and its growth rates were variable among the tested species. In the 31 remaining species the production of transformed roots was not observed under the conditions used in these experiments. Histochemical detection of β-glucuronidase (GUS) activity demonstrated the expression of this foreign gene in the hairy roots. PCR analyses demonstrated the presence of the rolB and nptII genes in the DNA of the transformed roots. The patterns of alkaloid-like compounds obtained by thin layer chromatography in some of the tested species were qualitatively similar between the transformed and non-transformed roots.

Tissue culture of ornamental cacti

“…The importance of transformed roots lies in their potential utilization as a source of metabolites, alkaloids and betalains for example, due to their biosynthetic potential and high rate of development in vitro ( Figure 4H and I). In the case of cactus, the only published study is of González-Díaz et al (2006) who evaluated the susceptibility of 65 species of 22 genera of Mexican cacti to Agrobacterium rhizogenes. Stem discs from in vitro cultured plants were infected with a suspension of the A4 agropine-type strain of Agrobacterium rhizogenes bearing the wild RiA4 plasmid and the binary vector pESC4 with the nptII and gus genes.…”

GENERACIÓN DE RAÍCES TRANSFORMADAS DE AGAVE SALMIANA Otto Y SU COLONIZACIÓN POR GLOMUS INTRARADICES

“…Con estas condiciones, de 57 a 63 % de los explantes inoculados generaron raíces transformadas. Esta eficiencia de transformación con A. rhizogenes es similar a la reportada previamente para algunas especies mexicanas de cactáceas (González-Díaz et al, 2006). Se encontró que a mayor concentración bacteriana y de acetosiringona, la eficiencia de generación de raíces transformadas aumentó.…”

“…El papel de la acetosiringona como inductora de los genes de virulencia de Agrobacterium (vir) y su uso para incrementar la eficiencia de transformación son ya bien conocidos. En el caso particular de la generación de raíces transformadas, la acetosiringona ha sido empleada con éxito en varias especies vegetales, entre ellas Pinus maximartinezii y P. pinceana (Villalobos et al, 2002), naranjo agrio (Citrus aurantium) (Chávez-Vela et al, 2003) y varias especies mexicanas de Cactáceas (González et al, 2006). También resultó claro que independientemente de la concentraciones bacteriana y de acetosiringona empleadas, la inoculación en el tallo siempre resultó más eficiente que en hojas o raíz.…”