An-2 Encodes a Cytokinin Synthesis Enzyme that Regulates Awn Length and Grain Production in Rice.
A wide range of morphological and physiological traits have changed between cultivated rice Oryza sativa and wild rice Oryza rufipogon under domestication. Here, we report cloning of the An-2 gene, encoding the Lonely Guy Like protein 6 (OsLOGL6), which catalyzes the final step of cytokinin synthesis in O. rufipogon. The near-isogenic line harboring a wild allele of An-2 in the genetic background of the awnless indica Guangluai 4 shows that An-2 promotes awn elongation by enhancing cell division, but decreases grain production by reducing grains per panicle and tillers per plant. We reveal that a genetic variation in the An-2 locus has a large impact on reducing awn length and increasing tiller and grain numbers in domesticated rice. Analysis of gene expression patterns suggests that An-1 regulates the formation of awn primordial, and An-2 promotes awn elongation. Nucleotide diversity of the An-2 locus in cultivated rice was found to be significantly reduced compared with that of wild rice, suggesting that the An-2 locus was subjected to artificial selection. We therefore propose that the selection of genetic variation in An-2 was due to reduced awn length and increased grain yield in cultivated rice.
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Benguo
B
Gu
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Taoying
T
Zhou
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Jianghong
J
Luo
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Hui
H
Liu
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Yongchun
Y
Wang
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Yingying
Y
Shangguan
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Jingjie
J
Zhu
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Yan
Y
Li
State Key Laboratory of Systematic and Evolutionary Botany, Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Tao
T
Sang
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
Zixuan
Z
Wang
National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China. Electronic address: bhan@ncgr.ac.cn.
Bin
B
Han
D000483:Alleles; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D003583:Cytokinins / Q000096:biosynthesis*; D002523:Edible Grain / Q000235:genetics; D017343:Genes, Plant; D005816:Genetic Complementation Test; D014644:Genetic Variation; D012275:Oryza / Q000201:enzymology / Q000235:genetics*; D040641:Quantitative Trait Loci; D012639:Seeds / Q000235:genetics / Q000254:growth & development
D003583:Cytokinins
Oryza sativa; awn; cytokinin synthesis enzyme; domestication; grain yield