Stacking three late blight resistance genes from wild species directly into African highland potato varieties confers complete field resistance to local blight races
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Date
2019
Journal Title
Journal ISSN
Volume Title
Publisher
Plant Biotechnology Journal
Abstract
Considered responsible for one million deaths in Ireland and widespread famine in the European
continent during the 1840s, late blight, caused by Phytophthora infestans, remains the most
devastating disease of potato (Solanum tuberosum L.) with about 15%–30% annual yield loss in
sub-Saharan Africa, affecting mainly smallholder farmers. We show here that the transfer of
three resistance (R) genes from wild relatives [RB, Rpi-blb2 from Solanum bulbocastanum and
Rpi-vnt1.1 from S. venturii] into potato provided complete resistance in the field over several
seasons. We observed that the stacking of the three R genes produced a high frequency of
transgenic events with resistance to late blight. In the field, 13 resistant transgenic events with
the 3R-gene stack from the potato varieties ‘Desiree’ and ‘Victoria’ grew normally without
showing pathogen damage and without any fungicide spray, whereas their non-transgenic
equivalent varieties were rapidly killed. Characteristics of the local pathogen population suggest
that the resistance to late blight may be long-lasting because it has low diversity, and essentially
consists of the single lineage, 2_A1, which expresses the cognate avirulence effector genes.
Yields of two transgenic events from ‘Desiree’ and ‘Victoria’ grown without fungicide to reflect
small-scale farm holders were estimated to be 29 and 45 t/ha respectively. This represents a
three to four-fold increase over the national average. Thus, these late blight resistant potato
varieties, which are the farmers’ preferred varieties, could be rapidly adopted and bring
significant income to smallholder farmers in sub-Saharan Africa.
Description
Keywords
GM potatoes, Transformation, Late blight resistance, Phytophthora infestans
Citation
Ghislain, M., Byarugaba, A. A., Magembe, E., Njoroge, A., Rivera, C., Román, M. L., ... & Kiggundu, A. (2019). Stacking three late blight resistance genes from wild species directly into African highland potato varieties confers complete field resistance to local blight races. Plant Biotechnology Journal, 17(6), 1119-1129. doi: 10.1111/pbi.13042