Establishment of embryogenic callus and transient gene expression in selected sugarcane varieties

Abstract

Twelve commercial sugarcane (Saccharum spp. hybrids) varieties were compared for both their ability to form white, embryogenic callus and their transformation potential. Of the 12 varieties investigated, NCo310, NCo376, N8, N12, N16, N18 and N20 produced large proportions of white, embryogenic (Type 3) callus in relation to total callus volume, especially when subcultured weekly on 1 mg l− 1 2,4-dichlorophenoxyacetic acid (2,4-D) for up to six weeks. Fortnightly subculture on 1 mg l− 1 2,4-D and on variable levels of 2,4-D were less effective in Type 3 callus maintenance. Transformation potential of the white callus from seven varieties was assessed by bombarding callus with a plasmid containing the genes which encode two anthocyanin transcriptional activators (pDP687). Expression of the inserted genes was measured after 48 h. Of all the varieties, NCo310 produced higher proportions of white callus, showed the best transient anthocyanin gene expression, and subsequent plantlet regeneration occurred, indicating that this variety is suitable for further transformation studies.