Silencing of six susceptibility genes results in potato late blight resistance

Abstract

Phytophthora infestans, the causal agent of late blight, is a major threat to commercial potato production worldwide. Significant costs are required for crop protection to secure yield. Many dominant genes for resistance (R-genes) to potato late blight have been identified, and some of these R-genes have been applied in potato breeding. However, the P. infestans population rapidly accumulates new virulent strains that render R-genes ineffective. Here we introduce a new class of resistance which is based on the loss-of-function of a susceptibility gene (S-gene) encoding a product exploited by pathogens during infection and colonization. Impaired S-genes primarily result in recessive resistance traits in contrast to recognition-based resistance that is governed by dominant R-genes. In Arabidopsis thaliana, many S-genes have been detected in screens of mutant populations. In the present study, we selected 11 A. thalianaS-genes and silenced orthologous genes in the potato cultivar Desiree, which is highly susceptible to late blight. The silencing of five genes resulted in complete resistance to the P. infestans isolate Pic99189, and the silencing of a sixth S-gene resulted in reduced susceptibility. The application of S-genes to potato breeding for resistance to late blight is further discussed.Electronic supplementary materialThe online version of this article (doi:10.1007/s11248-016-9964-2) contains supplementary material, which is available to authorized users.

GENETIC APPROACHES FOR ENGINEERING BIOTIC STRESS RESISTANCE IN POTATO (Solanum tuberosum L.)

“…Eleven S genes from Arabidopsis thaliana have been utilized to silence orthologous genes in cv. "Desiree" and resulted in replete resistance against, or plummeted susceptibility, to the late blight disease (Sun et al, 2016).…”

“…Concerning other biotic stresses in potatoes, RNAi technology has already been used for the development of transgenic potatoes resistant to PVY) (Missiou et al, 2004) and late blight (Sun et al, 2016). The technology can be implemented for the development of transgenic potatoes resistant against all types of biotic stresses.…”

Susceptibility genes : an additional source for improved resistance

“…RNAi transformants designated as RNAi:: StDND1-#5, #17; RNAi:: StDMR6-#5, #6; RNAi:: StDMR1-#24, #47 and described in Sun et al (2016b) were grown from in vitro plants. The RNAi tranformants are derivatives of the tetraploid potato cv Desiree, which is susceptible to late blight and used as susceptible control.…”

“…In our previous studies, RNAi transformants, RNAi::StDND1-#5, -#17; RNAi::StDMR6-#5, and -#6; RNAi::StDMR1-#24, and -#47, have been generated (Sun et al 2016 a and b). The expression levels of the StDND1, StDMR1 and StDMR6 genes in corresponding transformants have been evaluated by quantitative real-time (qRT)-PCR using gene-specific primers (Sun et al 2016b). Using the same methods, qRT-PCR was performed on the RNAi transformants used in this study and the reduced expression levels of the targeted S genes in the RNAi transformants were confirmed ( Supplementary Fig.…”

“…Recently, increased research on plant susceptibility genes (S genes) has led to a novel breeding strategy of deploying impaired host S genes to control diseases (Pavan et al 2011;Pessina et al 2014;Sun et al 2016b). In Arabidopsis, more than 150 S genes have been described (van Schie & Takken 2014).…”