Polymorphism and methylation patterns in Agave tequilana Weber var. ‘Azul’ plants propagated asexually by three different methods

Genetic variation in three forms of asexually propagated Agave tequilana Weber var. ‘Azul’ plants namely offsets, bulbils and in vitro cultured individuals was studied by AFLP analysis. Low levels of variation were observed between mother plants and offsets and a higher level between mother plant and bulbils. Families obtained from commercial plantations showed lower levels of variation in comparison to families grown as ornamentals. No variation was observed between the original explant and four generations of in vitro cultured plants. Epigenetic variation was also studied by analyzing changes in methylation patterns between mother plants and offspring in each form of asexual reproduction. Offsets and bulbils showed an overall decrease in methylation whereas in vitro cultured plants showed patterns specific to each generation: Generations 1 and 4 showed overall demethylation whereas Generations 2 and 3 showed increased methylation. Analysis of ESTs associated with transposable elements revealed higher proportions of ESTs from Ty1-copia-like, Gypsy and CACTA transposable elements in cDNA libraries obtained from pluripotent tissue suggesting a possible correlation between methylation patterns, expression of transposable element associated genes and somaclonal variation.

► Robust confirmation of low levels of genetic polymorphism in asexually cultured A. tequilana plants.
► Observation of differences in polymorphism levels between offsets and bulbils from the same mother plant.
► Determination of high levels of methylation change in all forms of asexual propagation.
► Association of differences between this study and others to the form of propagation (organogenesis).
► Identification of higher proportions of specific transposable element transcripts in pluripotent tissue.