Fine mapping a QTL for BYDV-PAV resistance in maize

Abstract

Barley yellow dwarf (BYD) is one of the economically most important virus diseases of cereals worldwide, causing yield losses of up to 80 %. BYD is caused by at least ten different phloem-limited viruses called BYD viruses (BYDVs) and Cereal yellow dwarf viruses (CYDVs). Means to control BYD are limited and the use of genetically resistant cultivars is the most economic and environmentally friendly approach. Maize plays a central role in the BYD infection cycle, serving as a reservoir for BYD-causing viruses and their vectors in summer. Growing BYD resistant maize varieties would reduce BYD pressure on maize and cereals. Using two biparental mapping populations, we were able to reduce a previously published QTL for BYDV-PAV resistance in maize to ~0.3 Mbp, comprising nine genes. Association mapping and gene expression analysis further reduced the number of candidate genes for BYDV-PAV resistance in maize to two: Zm00001eb428010 and Zm00001eb428020. Predicted functions of these genes suggest that they confer BYDV-PAV resistance either via interfering with virus replication or induction of ROS signaling. The sequence of one of these genes, Zm00001eb428010, is affected by a 54 bp deletion in the 5`-UTR and a protein altering variant in BYDV-PAV resistant maize inbreds but not BYDV-PAV susceptible and BYDV-PAV tolerant inbreds. This suggests that altered abundance and/or properties of the proteins that are encoded by Zm00001eb428010 may lead to BYDV-PAV resistance.