Factors affecting mango (Mangifera indica L.) protoplast isolation and culture

The major factors influencing protoplast isolation and culture of mango (Mangifera indica L.) cv. Kensington Pride were investigated. The resultant protocol was used to compare plating efficiency among 4 mango cultivars. Most responses differed between proembryonic masses (PEMs) and leaf sources. Protoplast yields of 15.22 × 106 g−1 from PEMs and 8.68 × 106 g−1 from greenhouse-derived leaves were obtained in a solution of 0.7 M mannitol CPW plus 1.5% cellulase, 1% hemicellulase and 0.75% macerozyme for PEMs or 0.5 M mannitol CPW plus 1.5% cellulose, 1% hemicellulase and 1.5% macerozyme for leaves. Culture in Ca-alginate beads with initial plating densities (IPD) of 2.5 × 104 Pp mL−1 for PEMs and 2.5 × 105 for leaves gave the highest plating efficiencies (FPE). For PEMs 1 mg L−1 2,4-d and 3.5 mg L−1 kinetin gave an FPE of 2.85% whereas lower kinetin (2 mg L−1) plus 0.5 mg L−1 6-BAP was most effective for leaves (FPE of 2.12%). Most protoplast mortality occurred during the first week of culture and was more severe in liquid culture. In Ca-alginate beads, protoplast survival at 14 days was higher for PEMs (30%) than leaf (21%) as was the frequency of cell division (17.6% compared to 13.6%). PEMs protoplasts continued development through embryogenesis to in vitro plantlet regeneration whereas leaf protoplasts underwent cell division up to 40-cell colonies but failed to proceed further. For PEMs, polyembryonic cvs. Kensington Pride and Keow Savoey produced higher FPE (1.95%) than monoembryonic cvs. Tommy Atkins and Keitt (1.75%). There was no effect of cultivar for leaf protoplasts.

► Workable yields of protoplast from proembryonic masses and glasshouse-derived leaves of mango were obtained.
► Cultures in alginate beads lead to the best subsequent development of the protoplasts.
► Leaf protoplasts produced cell colonies whereas PEMs protoplast produced plantlets.
► Differences in FPE of PEMs protoplasts between poly- and mono-embryonic cultivars were observed.
► No differences between cultivars were observed when leaf protoplasts were cultured