Gene Details:

• MSU gene ID: LOC_Os06g03710
• RAPdb gene ID: Os06g0127800
• Gene Symbol: DLT OsGRAS-32 D62 GS6 SMOS2
• Genome: MSU7 ,  IRGSP-1.0
• Species: Oryza sativa

Functional Descriptions:

• Briefly, these results demonstrated that the D62 (DLT/OsGRAS-32) not only participated in the regulation of BR signaling, but also influenced GA metabolism in rice.
• In addition, a ggc repeat region identified in the region that encodes the GRAS domain of GS6 played an important historic role in the domestication of grain size in rice.
• DWARF AND LOW-TILLERING (DLT) is a positive regulator that mediates several BR responses in rice.
• Here, we characterized a rice dwarf and low-tillering (DLT) mutant and cloned the corresponding gene via map-based cloning.
• In addition, both lamina bending and coleoptile elongation assays show that DLT is insensitive or much less responsive to brassinolide (BL), the most active BR, suggesting that DLT is involved in BR signaling.
• Here, we report the identification and cloning of Grain Size 6 (GS6), which plays an important role in reducing grain size in rice.
• GS6, a member of the GRAS gene family, negatively regulates grain size in rice.
• The expression levels of gibberellin (GA) biosynthetic genes including OsCPS1, OsKS1, OsKO1, OsKAO, OsGA20ox2/SD1 and OsGA2ox3 were significantly increased in D62 mutant.
• RT-PCR analysis and promoter activity analysis showed that the D62 gene expressed in all tested tissues including roots, stems, leaves and panicles of rice plant.
• Suppression of DLT can enhance the phenotypes of BR receptor mutant d61-1, and overexpression of DLT obviously suppressed the BR loss-of-function phenotypes of both d61-1 and Go, suggesting that DLT functions downstream of GSK2 to modulate BR responses.
• These results demonstrate that DLT is a GSK2 substrate, further reinforcing that the BIN2/GSK2 kinase has multiple substrates that carry out various BR responses.
• A dwarf mutant, dwarf 62 (D62), was isolated from rice cultivar 93-11 by mutagenesis with gamma-rays.
• Consistent with this conclusion, the accumulation of transcripts of BR biosynthesis genes in the DLT mutant indicated that DLT is involved in feedback inhibition of BR biosynthesis genes.
• Finally, consistent with the fact that DLT is also negatively feedback-regulated by BR treatment, a gel mobility shift assay showed that OsBZR1 can bind to the DLT promoter through the BR-response element.
• In previous studies, the DLT/OsGRAS-32 is confirmed to play positive roles in brassinosteroid (BR) signaling.
• Identification and characterization of dwarf 62, a loss-of-function mutation in DLT/OsGRAS-32 affecting gibberellin metabolism in rice.
• A premature stop at the +348 position in the coding sequence (CDS) of GS6 increased grain width and weight significantly.
• The D62 mutant exhibited decreased activity of alpha-amylase in endosperm and reduced content of endogenous GA(1).
• The dwarf phenotype of DLT is similar to BR-deficient or signaling mutants in rice.
• Knowledge of the function of GS6 might aid efforts to elucidate the molecular mechanisms that control grain development and evolution in rice plants, and could facilitate the genetic improvement of rice yield.
• DLT physically interacts with OSH15 to co-regulate many genes in seedlings and internodes.
• OSH15 targets and promotes the expression of the BR receptor gene BR INSENSITIVE1 (OsBRI1), and DLT facilitates this regulation in a dosage-dependent manner.
• Taken together, our results suggest that DLT interacts with OSH15, which functions in the lower internodes, to modulate rice internode elongation via orchestrating BR signaling and metabolism.
• Wide Grain 3, a GRAS Protein, Interacts with DLT to Regulate Grain Size and Brassinosteroid Signaling in Rice.
• Moreover, we found that WG3 directly interacts with DWARF AND LOW-TILLERING (DLT), a previously reported GRAS protein, and a genetic experiment demonstrated that WG3 and DLT function in a common pathway to regulate grain size.

Function-related keywords:

• BR-signaling ,  BR ,  domestication ,  dwarf ,  tillering ,  lamina ,  grain-size ,  gibberellin ,  ga ,  panicle ,  tiller ,  brassinosteroid ,  grain-width ,  endosperm ,  stem ,  grain ,  yield ,  root ,  seedlings ,  internode-elongation ,  Brassinosteroid ,  Brassinosteroid-Signaling

Literature:

• Identification and characterization of dwarf 62, a loss-of-function mutation in DLT/OsGRAS-32 affecting gibberellin metabolism in rice .  DOI:  10.1007/s00425-010-1263-1 ;  PMID:  20830595
• DWARF AND LOW-TILLERING acts as a direct downstream target of a GSK3/SHAGGY-like kinase to mediate brassinosteroid responses in rice .  DOI:  10.1105/tpc.112.097394 ;  PMID:  22685166
• DWARF AND LOW-TILLERING, a new member of the GRAS family, plays positive roles in brassinosteroid signaling in rice .  DOI:  10.1111/j.1365-313X.2009.03825.x ;  PMID:  19220793
• GS6, a member of the GRAS gene family, negatively regulates grain size in rice .  DOI:  10.1111/jipb.12062 ;  PMID:  23650998
• OrMKK3 Influences Morphology and Grain Size in Rice .  DOI:  10.1007/s12374-020-09290-2 ;  PMID:  33424241
• Rice DWARF AND LOW-TILLERING and the homeodomain protein OSH15 interact to regulate internode elongation via orchestrating brassinosteroid signaling and metabolism .  DOI:  10.1093/plcell/koac196 ;  PMID:  35789396
• Wide Grain 3, a GRAS Protein, Interacts with DLT to Regulate Grain Size and Brassinosteroid Signaling in Rice .  DOI:  10.1186/s12284-022-00601-4 ;  PMID:  36326916

Related News:

Gene Resources:

• NCBI ID: AK106449
• UniProt accessions:

Sequences: