qMrdd2, a novel quantitative resistance locus for maize rough dwarf disease

Abstract

Background Maize rough dwarf disease (MRDD), a widespread disease caused by four pathogenic viruses, severely reduces maize yield and grain quality. Resistance against MRDD is a complex trait that controlled by many quantitative trait loci (QTL) and easily influenced by environmental conditions. So far, many studies have reported numbers of resistant QTL, however, only one QTL have been cloned, so it is especially important to map and clone more genes that confer resistance to MRDD. Results In the study, a major quantitative trait locus (QTL) qMrdd2, which confers resistance to MRDD, was identified and fine mapped. qMrdd2, located on chromosome 2, was consistently identified in a 15-Mb interval between the simple sequence repeat (SSR) markers D184 and D1600 by using a recombinant inbred line (RIL) population derived from a cross between resistant (“80007”) and susceptible (“80044”) inbred lines. Using a recombinant-derived progeny test strategy, qMrdd2 was delineated to an interval of 577 kb flanked by markers N31 and N42. We further demonstrated that qMrdd2 is an incompletely dominant resistance locus for MRDD that reduced the disease severity index by 20.4%. Conclusions A major resistance QTL (qMrdd2) have been identified and successfully refined into 577 kb region. This locus will be valuable for improving maize variety resistance to MRDD via marker-assisted selection (MAS).

Functional analysis revealed the involvement of ZmABCB15 in resistance to rice black-streaked dwarf virus infection

“…Comparing resistant and susceptible materials is an efficient method to screen MRDD resistance genes. A large number of maize materials, including several resistant lines, such as ‘80007’, ‘K36’, ‘Mo17’, ‘Zheng58’, and ‘Zhengdan958’, and several susceptible lines, such as ‘80044’, ‘S221’, ‘Ye478’, ‘XH6’, ‘P138’, ‘Chang7–2’, and ‘Dan 340, were reported by different groups, providing abundant genetic materials for screening MRDD resistance genes [ 5 , 35 , 36 ]. Interestingly, a resistant varieties-specific inducted auxin transporter encoding gene, ZmABCB15 , was identified, suggesting a potential RBSDV resistance gene.…”