Transformation of Metschnikowia pulcherrima 320, biocontrol agent of storage rots, with the green fluorescent protein gene, GFP.

The yeast Metschnikowia pulcherrima (Pitt) M.W. Miller, isolate 320, showing antagonistic activity against Botrytis cinerea, causal agent of storage rot of table grapes, strawberry and kiwifruit, was transformed with the yeast-enhanced green fluorescent protein (yEGFP) gene, using plasmid pACT2.yEGFP and the lithium acetate protocol. Colonies expressing yEGFP were selected using an epifluorescence microscope. The antagonistic activity of five GFP transformants was evaluated on table grapes, cvs 'Matilde' and 'Italia', and compared to that of the M. pulcherrima 320 wild type. The activity of two transformants was indistinguishable from that of the parental strain, significantly reducing Botrytis storage rot; however, three transformants lost antagonistic activity completely. GFP-transformants and M. pulcherrima wild type showed the same growth rates in vitro. This appears to be the first report of M. pulcherrima transformation with the GFP gene.