Potato late blight field resistance from QTL dPI09c is conferred by the NB-LRR gene R8.

Rui Jiang,Zhendong Tian,Conghua Xie,Jack H Vossen,Hannele Lindqvist-Kreuze,Merideth Bonierbale,Jingcai Li,Miles Armstrong,Joanne Tze-Yin Lim,Jun Zhou,Ingo Hein,Juan Du,Katie Baker,Huan He,Leticia Portal

doi:10.1093/jxb/ery021

Abstract

Following the often short-lived protection that major nucleotide binding, leucine-rich-repeat (NB-LRR) resistance genes offer against the potato pathogen Phytophthora infestans, field resistance was thought to provide a more durable alternative to prevent late blight disease. We previously identified the QTL dPI09c on potato chromosome 9 as a more durable field resistance source against late blight. Here, the resistance QTL was fine-mapped to a 186 kb region. The interval corresponds to a larger, 389 kb, genomic region in the potato reference genome of Solanum tuberosum Group Phureja doubled monoploid clone DM1-3 (DM) and from which functional NB-LRRs R8, R9a, Rpi-moc1, and Rpi_vnt1 have arisen independently in wild species. dRenSeq analysis of parental clones alongside resistant and susceptible bulks of the segregating population B3C1HP showed full sequence representation of R8. This was independently validated using long-range PCR and screening of a bespoke bacterial artificial chromosome library. The latter enabled a comparative analysis of the sequence variation in this locus in diverse Solanaceae. We reveal for the first time that broad spectrum and durable field resistance against P. infestans is conferred by the NB-LRR gene R8, which is thought to provide narrow spectrum race-specific resistance.

Highlights

Potato (Solanum tuberosum L.) is the third most important consumption
We reveal for the first time that broad spectrum and durable field resistance against P. infestans is conferred by the NB-LRR gene R8, which is thought to provide narrow spectrum race-specific resistance
Further resistance assessment of these recombinants with P. infestans isolate PSR24 in whole-plant greenhouse tests revealed an approximate 1:1 segregation ratio of resistant recombinants that displayed less than 30% of leaf area infection with late blight and susceptible progenies that displayed more than this

Summary

Introduction

Potato (Solanum tuberosum L.) is the third most important consumption. More than a billion people worldwide consume food crop in the world after rice and wheat in terms of human potatoes, and global crop production exceeded 382 millionDownloaded from https://academic.oup.com/jxb/article-abstract/69/7/1545/4827645 by Library - Duncan of Jordanstone user on 09 April 20181546 | Jiang et al.metric tons in 2014 (FAO, 2017). Potato (Solanum tuberosum L.) is the third most important consumption. More than a billion people worldwide consume food crop in the world after rice and wheat in terms of human potatoes, and global crop production exceeded 382 million. Phytophthora infestans, the causal agent of late blight disease, is the most devastating pathogen of potato, causing losses of approximately $6.7 billion annually (Haas et al, 2009). Preventative application of chemicals is currently being used to control this disease. Excessive use of fungicides poses detrimental risks to human health and to the environment. Isolates can become insensitive to some of the commonly used agents (Goodwin et al, 1996). The characterization, cloning and introgression into cultivars of natural resistance provides an environmentally benign alternative to chemical crop protection agents

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Conclusion