Abstract:

Fusarium oxysporum f. sp. cubense (Foc) is one of the major threats to dessert banana (Musa spp.)
production. In Uganda, ‘Sukali Ndiizi’ is one of the most popular dessert banana cultivars and it is
highly susceptible to Fusarium wilt. Development of resistant cultivars through transgenic approaches
has shown to offer one of the most effective control options for most diseases. The transgenic
approaches for providing plant disease resistance have mainly been through either enzymatic
destruction of pathogen structures, neutralization of pathogen and its products or production of
metabolites that eventually kill the pathogen. However in recent years, methods that prevent cell death
of host plant after infection especially for necrotrophic pathogens like F. oxysporum have registered
success in providing resistance in several crops. We investigated whether the transgenic expression of
a programmed cell death inhibition gene in Sukali Ndiizi could be used to confer Fusarium resistance to
Foc race 1. Embryogenic cell suspensions of cv. ‘Sukali Ndiizi, were stably transformed with a
synthetic, plant-codon optimise mCed-9 gene. Twenty-eight independently transformed plant lines were
regenerated. The lines were inoculated with Foc race 1 and observed for 13 weeks in small-plant
glasshouse. Three transgenic lines showed significantly lower internal and external disease symptoms
than the wild-type susceptible ‘Sukali Ndiizi’ banana plants used as controls. This is the first report
from Africa on the generation of Fusarium wilt tolerant transgenic ‘Sukali Ndiizi’, a very popular but
rapidly diminishing African dessert banana.