Hunting for the genetic loci underlying root lodging resistance by BSR-seq and QTL mapping in maize
摘要
Lodging is one of the major factors that affect mechanical harvesting and decreases yield and quality of maize. Exploring quantitative trait loci (QTL) or genes underlying lodging resistance is vital for molecular breeding of lodging-resistant maize varieties. Specially, root lodging resistance (RLR) QTLs or genes are rarely reported.
ResultsIn this study, to explore the QTLs underlying root lodging resistance, we generated a F2 population of CIMBL74 and CIMBL145 that have contrastive difference of root architecture and lodging resistance. We performed BSR-seq analysis of the populations and 8 QTLs were identified. Among them, qRLR1, qRLR4, qRLR5 and qRLR6 were further confirmed by chromosomal region-based association study (CRAS) and/or linkage mapping. Based on the integrated analysis, 40 and 266 candidate genes, including root development- and cell wall-related genes, were identified in qRLR4 and qRLR6, respectively. Among them, the ZmNRT5 (encoding a nitrate transporter) located in qRLR6 was identified as a strong candidate gene based on candidate gene association analysis and haplotype analysis. Moreover, the expression level of ZmNRT5 in CIMBL74 was significantly lower than in CIMBL145.
ConclusionThis study provides valuable QTLs and candidate genes for maize improvement toward enhanced root lodging resistance.