Agrobacterium-mediated transformation of Phaseolus acutifolius A Gray

Agrobacterium-mediated transformation of Phaseolus acutifolius A. Gray has been achieved. Regeneration-competent callus, obtained from bud explants of greenhouse-grown plants, was co-cultivated with Agrobacterium tumefaciens C58C1Rif(R)(pMP90) harbouring a binary vector with the neomycin phosphotransferase II (nptII) and beta-glucuronidase (uidA) marker genes. Transient expression of uidA was detected in five out of six genotypes tested. Transgenic callus lines of three genotypes were established on geneticin-containing medium. Plants were recovered from one line (genotype NI 576). This line had been transformed with a binary plasmid which, in addition to the marker genes, contained a genomic fragment encoding the Phaseolus vulgaris arcelin-5a protein. This seed storage protein presumably confers resistance to the insect Zabrotes subfasciatus, a major pest of P. vulgaris. Integration of foreign DNA was confirmed by molecular analysis. The introduced genes segregated as a single locus. Arcelin-5a was produced at high levels in seeds. The possibility of using P. acutifolius as a 'bridging' species to introduce transgenes into the economically more important species P. vulgaris is discussed.