Cytokinin oxidase regulates rice grain production.
Most agriculturally important traits are regulated by genes known as quantitative trait loci (QTLs) derived from natural allelic variations. We here show that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinin. Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield. QTL pyramiding to combine loci for grain number and plant height in the same genetic background generated lines exhibiting both beneficial traits. These results provide a strategy for tailormade crop improvement.
Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
Motoyuki
M
Ashikari
Hitoshi
H
Sakakibara
Shaoyang
S
Lin
Toshio
T
Yamamoto
Tomonori
T
Takashi
Asuka
A
Nishimura
Enrique R
ER
Angeles
Qian
Q
Qian
Hidemi
H
Kitano
Makoto
M
Matsuoka
D000483:Alleles; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018556:Crops, Agricultural / Q000235:genetics / Q000254:growth & development; D003433:Crosses, Genetic; D003583:Cytokinins / Q000378:metabolism*; D035264:Flowers / Q000254:growth & development / Q000378:metabolism; D020869:Gene Expression Profiling; D017343:Genes, Plant; D018519:Meristem / Q000378:metabolism; D012275:Oryza / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D015026:Zeatin / Q000378:metabolism
D003583:Cytokinins; D015026:Zeatin; D010088:Oxidoreductases; C019984:cytokinin oxidase