Gene Details:

• MSU gene ID: LOC_Os04g39430
• RAPdb gene ID: Os04g0469800
• Gene Symbol: D11 CPB1 CYP724B1 GNS4 PMM1
• Genome: MSU7 ,  IRGSP-1.0
• Species: Oryza sativa

Functional Descriptions:

• Molecular and biochemical studies reveal that two different cytochrome P450s, CYP90B2/OsDWARF4 and CYP724B1/D11, function redundantly in C-22 hydroxylation, the rate-limiting step of brassinosteroid biosynthesis.
• The gene was found to encode a novel cytochrome P450 (CYP724B1), which showed homology to enzymes involved in brassinosteroid (BR) biosynthesis.
• Precise determination of the defective step(s) in BR synthesis in D11 mutants proved intractable because of tissue specificity and the complex control of BR accumulation in plants.
• However, 6-deoxotyphasterol (6-DeoxoTY) and typhasterol (TY), but not any upstream intermediates before these compounds, effectively restored BR response in D11 mutants in a lamina joint bending assay.
• Multiple lines of evidence together suggest that the D11/CYP724B1 gene plays a role in BR synthesis and may be involved in the supply of 6-DeoxoTY and TY in the BR biosynthesis network in rice.
• Consistently, transcriptome analyses revealed that SDG725 depletion results in down-regulation by more than two-fold of over 1000 genes, including D11, BRI1 and BU1, which are known to be involved in brassinosteroid biosynthesis or signaling pathways.
• Furthermore, RAVL1 is also required for the expression of the BR biosynthetic genes D2, D11, and BRD1 that are subject to BR negative feedback.
• We have characterized a rice (Oryza sativa) dwarf mutant, dwarf11 (D11), that bears seeds of reduced length.
• To understand the mechanism by which seed length is regulated, the D11 gene was isolated by a map-based cloning method.
• The dwarf phenotype of D11 mutants was restored by the application of the brassinolide (BL).
• Overexpression of CPB1/D11 under the background of CPB1 mutant not only rescued normal panicle architecture and plant height, but also had a larger leaf angle and seed size than the controls.
• Genetic transformation experiments confirmed that a His360Leu amino acid substitution residing in the highly conserved region of CPB1/D11 was responsible for the panicle architecture and seed size changes in the CPB1 mutants.
• Overexpression of GNS4 significantly increased organ size, 1000-grain weight, and panicle size, and subsequently enhanced grain yields in both the Nipponbare and Wuyunjing7 (a high-yielding cultivar) backgrounds.
• A single nucleotide polymorphism (deletion) in the promoter region of GNS4 reduced its expression level in the mutant, leading to reduced grain number and smaller grains.
• Morphological and cellular analyses suggested that GNS4 positively regulates grain size by promoting cell elongation.
• GNS4 was identified as a positive regulator of grain number and grain size in rice.
• We characterized a rice mutant GNS4 (grain number and size on chromosome 4) with reduced organ size, fewer grains per panicle, and smaller grains compared with those of WT.
• Map-based cloning indicated that the GNS4 gene, encoding a cytochrome P450 protein, is a novel allele of DWARF11 (D11).
• These results suggest that GNS4 is key target gene with possible applications in rice yield breeding.
• GNS4 can be targeted in breeding programs to increase yields.
• Overall, it can be concluded that PMM1 is an important gene involved in BRs biosynthesis and affecting the differentiation of spikelet primordia and patterns of panicle branches in rice.
• Overexpression of D4 could successfully rescue the abnormal panicle architecture of PMM1 plants, indicating that PMM1/D11 and D4 function redundantly in BRs biosynthesis.
• PMM1 is a new allele of DWARF11 (D11) PMM1 transcripts are preferentially expressed in young panicles, particularly expressed in the primordia of branches and spikelets during inflorescence development.
• Map-based cloning revealed that a large fragment deletion from the 2nd to 9th exons of PMM1 was responsible for the clustered primary branch morphology in PMM1-1.
• Thus, our results demonstrated that PMM1 determines the inflorescence architecture by controlling brassinosteroid biosynthesis in rice.

Function-related keywords:

• brassinosteroid ,  dwarf ,  BR ,  lamina ,  seed ,  leaf ,  panicle ,  architecture ,  seed-size ,  panicle-architecture ,  grain ,  grains-per-panicle ,  grain-number ,  map-based-cloning ,  grain-yield ,  yield ,  grain-size ,  cell-elongation ,  breeding ,  grain-weight ,  organ-size ,  panicle-size ,  spikelet ,  development ,  inflorescence ,  inflorescence-architecture ,  Brassinosteroid

Literature:

• H3K36 methylation is critical for brassinosteroid-regulated plant growth and development in rice .  DOI:  10.1111/j.1365-313X.2011.04873.x ;  PMID:  22136623
• Erect leaves caused by brassinosteroid deficiency increase biomass production and grain yield in rice .  DOI:  10.1038/nbt1173 ;  PMID:  16369540
• A novel cytochrome P450 is implicated in brassinosteroid biosynthesis via the characterization of a rice dwarf mutant, dwarf11, with reduced seed length .  DOI:  10.1105/tpc.104.024950 ;  PMID:  15705958
• RAV-Like1 maintains brassinosteroid homeostasis via the coordinated activation of BRI1 and biosynthetic genes in rice .  DOI:  10.1105/tpc.109.069575 ;  PMID:  20581303
• CLUSTERED PRIMARY BRANCH 1, a new allele of DWARF11, controls panicle architecture and seed size in rice .  DOI:  10.1111/pbi.12391 ;  PMID:  25923523
• GNS4, a novel allele of DWARF11, regulates grain number and grain size in a high-yield rice variety .  DOI:  10.1186/s12284-017-0171-4 ;  PMID:  28730412
• Panicle Morphology Mutant 1 (PMM1) determines the inflorescence architecture of rice by controlling brassinosteroid biosynthesis .  DOI:  10.1186/s12870-018-1577-x ;  PMID:  30541444
• Notched Belly Grain 4, a Novel Allele of Dwarf 11, Regulates Grain Shape and Seed Germination in Rice (Oryza sativa L.) .  DOI:  10.3390/ijms19124069 ;  PMID:  30558382

Related News:

Gene Resources:

• NCBI ID: AB158759
• UniProt accessions:

Sequences: