Synchronized somatic embryo development in embryogenic suspensions of grapevine Muscadinia rotundifolia (Michx.) Small

Abstract

High-frequency, synchronous embryogenic systems in liquid culture facilitate plant regeneration and can be used as an essential model for performing functional genomics studies and understanding molecular aspect of the ontogenesis of higher plants. In the present study, synchronous somatic embryogenic cultures were developed for Muscadinia rotundifolia cv. Darlene and Vitis vinifera cv. Velika. High cell density and presence of 2,4-dichlorophenoxyacetic acid (2,4-D) proved to be essential for the establishment of the suspension cultures. Low cell density and continuous availability of auxin (2,4-D) was crucial for maintenance of suspension cultures. High cell density and withdrawal of 2,4-D is sufficient to advance somatic embryo development toward embryo differentiation and plantlets regeneration. Cells and cell clusters fractionation by density gradient centrifugation in Ficoll solution demonstrated to be a suitable method for separation of subpopulations with various potential for embryo development. The high frequency of synchronous development and differentiation of somatic embryos was attained essentially for the heaviest (at 16-18 % and >18 % Ficoll layer) cell population.