Fine mapping SPP1, a QTL controlling the number of spikelets per panicle, to a BAC clone in rice (Oryza sativa).
Near isogenic lines (NILs) can be used to efficiently handle a target quantitative trait locus (QTL) by blocking genetic background noise. One QTL, SPP1, which controls the number of spikelets per panicle (SPP), was located on chromosome 1, near Gn1a, a cloned gene for rice production in a recombinant inbred line population. NILs of the SPP1 regions were quickly obtained by self-crossing recombinant inbred line 30 which is heterozygous around SPP1. Using a random NIL-F(2) population of 210 individuals, we mapped SPP1 to a 2.2-cM interval between RM1195 and RM490, which explained 51.1% of SPP variation. The difference in SPP between the two homozygotes was 44. F(2)-1456, one NIL-F(2) plant, was heterozygous in the SPP1 region but was fixed in the region of Gn1a gene. This plant F(3) family showed a very wide variation in SPP, which suggested that it was SPP1 but Gn1a affected the variation of SPP in this population. In a word, SPP1 is a novel gene distinct from Gn1a. Four newly developed InDel markers were used for high-resolution mapping of SPP1 with a large NIL-F(2) population. Finally, it was narrowed down to a bacterial artificial chromosome clone spanning 107 kb; 17 open reading frames have been identified in the region. Of them, LOC_Os01g12160, which encodes an IAA synthetase, is the most interesting candidate gene.
Liu
Touming
T
National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070, Wuhan, China.
Mao
Donghai
D
Zhang
Shengpeng
S
Xu
Caiguo
C
Xing
Yongzhong
Y
D000483:Alleles; D022202:Chromosomes, Artificial, Bacterial; D032461:Chromosomes, Plant; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D017343:Genes, Plant; D005819:Genetic Markers; D014644:Genetic Variation; D018745:Genome, Plant; D006720:Homozygote; D018895:Microsatellite Repeats; D016366:Open Reading Frames; D012275:Oryza / Q000235:genetics*; D020161:Physical Chromosome Mapping; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic
D018744:DNA, Plant; D005819:Genetic Markers