Morphogenetic stability of variegated Vanilla planifolia Jacks. plants micropropagated in a temporary immersion system (TIB®)

Abstract

ISSR markers are useful to identify molecular changes in variegated vanilla (Vanilla planifolia Jacks.) plants derived from a temporary immersion system. Clonal propagation through in vitro cultures produces individuals that are identical to the parent plant from which they were subcultured. However, there is evidence of phenotypic variations between propagated clones. The most common phenotypic variations are changes in leaf pigmentation, i.e., variegated individuals. Many such phenotypic variations are exploited by the ornamental industry. In a previous study by our group on indirect organogenesis in vanilla (Ramirez-Mosqueda and Iglesias-Andreu in In Vitro Cell Dev Biol Plant 52:154–160, 2015), variegated Vanilla planifolia Jacks. plants were generated in vitro. A temporary immersion system allows for the mass propagation of plant material in liquid culture. The present study aimed to identify morphological and molecular changes that occurred in variegated plants obtained during micropropagation in a temporary immersion system, the TIB®. To achieve this, the morphology of plants micropropagated in TIB® was assessed and analyzed at the molecular level using inter-simple sequence repeats. Molecular variation was analyzed over four subcultures, each lasting 45 days. Plants showed 100% uniformity (monomorphism) and morphological stability, which were confirmed by the heritability of leaf pigmentation (variegated individuals) in all micropropagated plants over all four subcultures. This study demonstrates that high genetic and morphological stability was achieved in variegated V. planifolia genotypes that were micropropagated in TIB®. This would allow for the establishment of a clonal line of variegated plants with ornamental applications. In addition, 100% survival of the plants was observed during acclimatization. The study forms part of a wider long-term effort to assess the potential of mass propagation of variegated vanilla for ornamental purposes.