Late Blight Resistance of RB Transgenic Potato Lines

Abstract

<jats:p>Late blight of potato (<jats:italic>Solanum tuberosum</jats:italic> L.), incited by <jats:italic>Phytophthora infestans</jats:italic> (Mont.) de Bary, is a devastating disease affecting tuber yield and storage. Recent work has isolated a resistance gene, <jats:italic>RB</jats:italic>, from the wild species <jats:italic>Solanum bulbocastanum</jats:italic> Dun. Earlier work in Toluca, Mexico, observed significant levels of field resistance under intense disease pressure in a somatic hybrid containing <jats:italic>RB</jats:italic>. In this study, five transgenic <jats:italic>RB</jats:italic> lines were recovered from the late blight susceptible line MSE149-5Y, from the Michigan State University (MSU) potato breeding program. Transgenic lines were molecularly characterized for the <jats:italic>RB</jats:italic> transgene, <jats:italic>RB</jats:italic> transcript, and insertion number of the kanamycin resistance gene <jats:italic>NPTII</jats:italic>. Transgenic lines and the parent line were evaluated for resistance in field and laboratory tests. Molecular characterization alone did not predict which lines were resistant. Three of the <jats:italic>RB</jats:italic> transformed MSE149-5Y lines showed increased resistance under field conditions at MSU and increased resistance in detached leaf evaluations using multiple isolates individually (US-1, US-1.7, US-8, US-10, and US-14). Transfer of <jats:italic>RB</jats:italic> into late blight susceptible and resistant lines could provide increased protection to potato late blight. The use of the <jats:italic>RB</jats:italic> gene for transformation in this way creates a partially cisgenic event in potato because the gene's native promoter and terminator are used. This type of transformation provides a chance to generate greater public acceptance of engineered approaches to trait introgression in food crops.</jats:p>

Developing Cold‐Chipping Potato Varieties by Silencing the Vacuolar Invertase Gene

“…Thus, improvement of specific traits in popular processing cultivars using genetic engineering could be a highly effective, rapid, and economical approach for potato improvement. The potential of this approach has been well demonstrated by genetic engineering for several important potato traits including resistance to potato late blight (Halterman et al, 2008; Kuhl et al, 2007) and high‐amylose starch (Schwall et al, 2000). Genetically modified low amylose potatoes were approved for commercial release in Europe in 2010 (Ryffel, 2010).…”

Understanding and Exploiting Late Blight Resistance in the Age of Effectors

“…Besides classical breeding, the cloning of Rpi-blb1/RB has opened the possibility of producing resistant potatoes with increased resistance to late blight by direct transfer of the gene using recombinant DNA techniques (70). However, the exploitation of Rpi-blb1 may be complicated by the observation that when introduced into cultivated potato, this gene confers only partial resistance to aggressive isolates.…”

Stacking three late blight resistance genes from wild species directly into African highland potato varieties confers complete field resistance to local blight races

“…No known isolates were virulent on both wild species and none had been identified that were able to overcome all three R genes (Vleeshouwers and Oliver, 2014;Vleeshouwers et al, 2011). The RB gene, also referred to as Rpi-blb1, has been shown to slow down lesion development and to confer partial field resistance to LB (Chen and Halterman, 2011;Halterman et al, 2008;Kuhl et al, 2007). A transcript dose-response was documented for resistance to foliar LB, but also for tuber resistance (Bradeen et al, 2009;Kramer et al, 2009;Millett et al, 2015).…”