ANALYSIS OF THE SOMACLONAL VARIATION IN TWO IN VITRO REGENERATED AGAVE SPECIES

Abstract

Plant tissue culture has been shown to be an efficient technique for the propagation of diverse Agave species using different in vitro regeneration processes. However, it has been demonstrated that genetic changes can occur in plants regenerated under these schemes, also called somaclonal variation. Objective: the objective of this study was to determine the genetic fidelity of plantlets regenerated from three different explants (mature zygotic embryonic axis, in vitro plantlet meristematic zone, and ex vitro plantlet meristematic zone) using two pathways of micropropagation (direct and indirect organogenesis) of A. salmiana and A. marmorata. Methodology: somaclonal variation of the obtained clones was evaluated using different DNA markers, such as anchored simple inter-sequence repeat (ASSR) and random amplified polymorphic DNA (RAPD). Results: the results show that only in those clones that undergo a callus phase and, consequently, indirect organogenesis, somaclonal variation was observed. In contrast, those clones obtained by direct organogenesis were genetically stable, it means not polymorphic bands were observed. Implications: it was achieved an efficient propagation protocol for A. salmiana and A. marmorata, maintaining genetic stability of regenerated plantlets as well as a possible alternative for genetic improvement by observing somaclonal variation via indirect organogenesis in both evaluated species. Conclusions: in this research, the micropropagation pathway (direct and indirect organogenesis) was the determining factor to maintain or not the genetic fidelity of the regenerated plants in both species of Agave used.