QTL-seq identifies an early flowering QTL located near Flowering Locus T in cucumber.
Next-generation sequencing enabled a fast discovery of a major QTL controlling early flowering in cucumber, corresponding to the FT gene conditioning flowering time in Arabidopsis. Next-generation sequencing technologies are making it faster and more efficient to establish the association of agronomic traits with molecular markers or candidate genes, which is the requirement for marker-assisted selection in molecular breeding. Early flowering is an important agronomic trait in cucumber (Cucumis sativus L.), but the underlying genetic mechanism is unknown. In this study, we identified a candidate gene for early flowering QTL, Ef1.1 through QTL-seq. Segregation analysis in F2 and BC1 populations derived from a cross between two inbred lines "Muromskij" (early flowering) and "9930" (late flowering) suggested quantitative nature of flowering time in cucumber. Genome-wide comparison of SNP profiles between the early and late-flowering bulks constructed from F2 plants identified a major QTL, designated Ef1.1 on cucumber chromosome 1 for early flowering in Muromskij, which was confirmed by microsatellite marker-based classical QTL mapping in the F2 population. Joint QTL-seq and traditional QTL analysis delimited Ef1.1 to an 890 kb genomic region. A cucumber gene, Csa1G651710, was identified in this region, which is a homolog of the FLOWERING LOCUS T (FT), the main flowering switch gene in Arabidopsis. Quantitative RT-PCR study of the expression level of Csa1G651710 revealed significantly higher expression in early flowering genotypes. Data presented here provide support for Csa1G651710 as a possible candidate gene for early flowering in the cucumber line Muromskij.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of Ministry of Agriculture, Sino-Dutch Joint Lab of Horticultural Genomics, Institute of Vegetables and Flowers, CAAS, Beijing, 100081, China.
Hongfeng
H
Lu
Tao
T
Lin
Joël
J
Klein
Shenhao
S
Wang
Jianjian
J
Qi
Qian
Q
Zhou
Jinjing
J
Sun
Zhonghua
Z
Zhang
Yiqun
Y
Weng
Sanwen
S
Huang
D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D018553:Cucumis sativus / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D005819:Genetic Markers; D018745:Genome, Plant; D005838:Genotype; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci
D005819:Genetic Markers