Dominant and pleiotropic effects of a GAI gene in wheat results from a lack of interaction between DELLA and GID1.
Dominance, semidominance, and recessiveness are important modes of Mendelian inheritance. The phytohormone gibberellin (GA) regulates many plant growth and developmental processes. The previously cloned semidominant GA-insensitive (GAI) genes Reduced height1 (Rht1) and Rht2 in wheat (Triticum aestivum) were the basis of the Green Revolution. However, no completely dominant GAI gene has been cloned. Here, we report the molecular characterization of Rht-B1c, a dominant GAI allele in wheat that confers more extreme characteristics than its incompletely dominant alleles. Rht-B1c is caused by a terminal repeat retrotransposons in miniature insertion in the DELLA domain. Yeast two-hybrid assays showed that Rht-B1c protein fails to interact with GA-INSENSITIVE DWARF1 (GID1), thereby blocking GA responses and resulting in extreme dwarfism and pleiotropic effects. By contrast, Rht-B1b protein only reduces interaction with GID1. Furthermore, we analyzed its functions using near-isogenic lines and examined its molecular mechanisms in transgenic rice. These results indicated that the affinity between GID1 and DELLA proteins is key to regulation of the stability of DELLA proteins, and differential interactions determine dominant and semidominant gene responses to GA.
Key Laboratory of Crop Germplasm Resources and Utilization, Ministry of Agriculture, National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Jing
J
Wu
Xiuying
X
Kong
Jianmin
J
Wan
Xueying
X
Liu
Xin
X
Zhang
Xiuping
X
Guo
Ronghua
R
Zhou
Guangyao
G
Zhao
Ruilian
R
Jing
Xiangdong
X
Fu
Jizeng
J
Jia
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant / Q000235:genetics; D005875:Gibberellins / Q000378:metabolism* / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D025941:Protein Interaction Mapping; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D018076:DNA, Complementary; D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins