Callus formation from cultured protoplasts of banana ( Musa sp.)

Abstract

Protoplasts were isolated from cell suspension initiated from calli of immature seeds of Musa acuminata ssp. burmannica cv Long Tavoy (AA). When co-cultured at high density with a reliable feeder culture, the protoplasts underwent sustained divisions and formed callus. Cytological studies showed that the cells of protoplast-derived calli had embryogenic characteristics as the cell suspensions used as protoplast source. Analysis of isoenzymes, in particular phosphoglucomutase (PGM) and alcohol dehydrogenase (ADH), distinguished the Lolium feeder cells from the protoplast-derived calli of banana and confirmed the Musa nature of these calli. The response of protoplasts depended upon the specificity of the feeder-physical barrier interaction. As a matter of fact, Lolium feeder induced a high rate of growth of protoplast-derived calli when combined with the use of Millipore membrane, used as a physical barrier keeping separate the protoplast culture from the feeder. Banana feeder gave similar results if nylon mesh was used as a physical barrier. The addition of dimethylsulfoxide (DMSO) to the feeder culture neither increased the proliferation of nurse cells nor affected the growth of protoplast-derived calli of banana.