title: OsGA20ox1, a candidate gene for a major QTL controlling seedling vigor in rice.
abstract: Seedling vigor is among the major determinants of stable stand establishment in direct-seeded rice (Oryza sativa L.) in temperate regions. Quantitative trait loci (QTL) for seedling vigor were identified using 250 recombinant inbred lines (RILs) derived from a cross between two japonica rice cultivars Kakehashi and Dunghan Shali. Seedling heights measured at 14 days after sowing were 20.3 and 29.4 cm for Kakehashi and Dunghan Shali, respectively. For the RILs, the height ranged from 14.1 to 31.7 cm. Four putative QTLs associated with seedling height were detected. qPHS3-2, the major QTL that was located on the long arm of chromosome 3, accounted for 26.2 % of the phenotypic variance. Using progeny of the near isogenic lines (NILs) produced by the backcross introduction of a chromosome segment carrying this major QTL into an elite cultivar Iwatekko, we fine-mapped qPHS3-2 to a 81-kb interval between two markers, ID_CAPS_01 and RM16227. Within this mapped region, we identified the gene OsGA20ox1, which is related to gibberellin (GA) biosynthesis. The relative expression levels of GA20ox1 in seedlings of Dunghan Shali and NILs were higher than that of Iwatekko. Concomitantly, the amount of endogenous active GA was higher in Dunghan Shali and the NILs compared to the level detected in Iwatekko. These results indicate that OsGA20ox1 is a strong candidate gene for major QTL controlling seedling vigor in rice.
authors.affiliation: Iwate Agricultural Research Center, 20-1, Narita, Kitakami, Iwate 024-0003, Japan. a-abe@pref.iwate.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Abe
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takagi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujibe
authors.forename: Koichiro
authors.initials: K
authors.lastname: Aya
authors.forename: Mikiko
authors.initials: M
authors.lastname: Kojima
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sakakibara
authors.forename: Aiko
authors.initials: A
authors.lastname: Uemura
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Ryohei
authors.initials: R
authors.lastname: Terauchi
mesh_terms: D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D056726:Genetic Association Studies; D005838:Genotype; D018525:Germination; D005875:Gibberellins / Q000378:metabolism; D007178:Inbreeding; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D020161:Physical Chromosome Mapping; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D040641:Quantitative Trait Loci / Q000235:genetics*; D036226:Seedlings / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism
chemical_list: D005875:Gibberellins; D010940:Plant Proteins