Agrobacterium-mediated transformation of Phaseolus acutifolius A. Gray
has been achieved. Regeneration-competent callus, obtained from bud e
xplants of greenhouse-grown plants, was co-cultivated with Agrobacteri
um tumefaciens C58C1Rif(R)(pMP90) harbouring a binary vector with the
neomycin phosphotransferase II (nptII) and beta-glucuronidase (uidA) m
arker 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 bin
ary plasmid which, in addition to the marker genes, contained a genomi
c fragment encoding the Phaseolus vulgaris arcelin-5a protein. This se
ed storage protein presumably confers resistance to the insect Zabrote
s subfasciatus, a major pest of P. vulgaris. Integration of foreign DN
A was confirmed by molecular analysis. The introduced genes segregated
as a single locus. Arcelin-5a was produced at high levels in seeds. T
he possibility of using P. acutifolius as a 'bridging' species to intr
oduce transgenes into the economically more important species P. vulga
ris is discussed.