Gene Details:

• MSU gene ID: LOC_Os01g72370
• RAPdb gene ID: Os01g0952800
• Gene Symbol: OsIRO2 OsbHLH056
• Genome: MSU7 ,  IRGSP-1.0
• Species: Oryza sativa

Functional Descriptions:

• Of these genes, a putative basic helix-loop-helix (bHLH) transcription factor gene, named OsIRO2, was strongly expressed in both roots and shoots during Fe deficiency stress.
• OsIRO2 expression in vegetative tissues was restricted almost exclusively to vascular bundles of roots and leaves, and to the root exodermis under Fe-sufficient conditions, and expanded to all tissues of roots and leaves in response to Fe deficiency.
• Microarray analysis demonstrated that OsIRO2 regulates 59 Fe-deficiency-induced genes in roots.
• Gene expression analysis of rice iron-regulated bHLH transcription factor OsIRO2, nicotianamine synthases 1 and 2 (NAS1 and NAS2), yellow-stripe like transporter 15 (YSL15) and iron-regulated transporter (IRT1) indicated that ethylene caused an increase in transcript abundance of both Fe (II) and Fe (III)-phytosiderophore uptake systems.
• RNA interference of OsIRO2 in transgenic rice showed that ethylene acted via this transcription factor to induce the expression of OsNAS1, OsNAS2, OsYSL15, and OsIRT1.
• To elucidate the regulation mechanisms of the genes related to Fe acquisition in graminaceous plants, we characterized the Fe-deficiency-inducible basic helix-loop-helix transcription factor OsIRO2 in rice.
• Some of these genes, including two transcription factors upregulated by Fe deficiency, possessed the OsIRO2 binding sequence in their upstream regions.
• We propose a novel gene regulation network for Fe-deficiency responses, including OsIRO2, IDEs and the two transcription factors.
• Previously, we reported that an Fe-deficiency-inducible basic helix-loop-helix (bHLH) transcription factor, OsIRO2, is responsible for regulation of the genes involved in Fe homeostasis in rice.
• Plants overexpressing OsIRO2 grew better, and OsIRO2-repressed plants showed poor growth compared to non-transformant rice after germination.
• OsIRO2 is responsible for iron utilization in rice and improves growth and yield in calcareous soil.
• These results suggest that OsIRO2 is synchronously expressed with genes involved in Fe homeostasis, and performs a crucial function in regulation not only of Fe uptake from soil but also Fe transport during germination and Fe translocation to grain during seed maturation.
• OsIRO2 expression was also detected in flowers and developing seeds.
• In this study, we produced a new Fe deficiency-tolerant rice by the additional introduction of a barley IDS3 genome fragment with refre1/372 and OsIRO2 (named as IRI lines) for further enhancement in Strategy II phytosiderophore productivity and better growth performance in various environments.
• Our results show that an enhanced tolerance was observed in OsIRO2 introduced line at the early growth stage, refre1/372 introduced line in the late stage, and RI line in all stages among five types of cultivation method.
• Enhancement of Iron Acquisition in Rice by the Mugineic Acid Synthase Gene With Ferric Iron Reductase Gene and OsIRO2 Confers Tolerance in Submerged and Nonsubmerged Calcareous Soils.
• Moreover, we demonstrated that new IRI rice lines exhibited enhanced tolerance to Fe deficiency compared to nontransgenic (NT) rice and rice lines harboring the overexpressing OsIRO2 or the IDS3 fragment under submerged calcareous soil.
• OsIRO3 negatively regulates Fe homeostasis by repressing the expression of OsIRO2.

Function-related keywords:

• root ,  vegetative ,  transporter ,  ethylene ,  transcription-factor ,  shoot ,  vascular-bundle ,  growth ,  grain ,  homeostasis ,  flower ,  yield ,  iron ,  seed ,  tolerance ,  Fe-homeostasis

Literature:

• Ethylene is involved in the regulation of iron homeostasis by regulating the expression of iron-acquisition-related genes in Oryza sativa .  DOI:  10.1093/jxb/erq301 ;  PMID:  21112958
• Isolation and characterization of IRO2, a novel iron-regulated bHLH transcription factor in graminaceous plants .  DOI:  10.1093/jxb/erl054 ;  PMID:  16887895
• A receptor-like protein RMC is involved in regulation of iron acquisition in rice .  DOI:  10.1093/jxb/ert290 ;  PMID:  24014863
• The rice bHLH protein OsIRO2 is an essential regulator of the genes involved in Fe uptake under Fe-deficient conditions .  DOI:  10.1111/j.1365-313X.2007.03149.x ;  PMID:  17559517
• The rice transcription factor IDEF1 is essential for the early response to iron deficiency, and induces vegetative expression of late embryogenesis abundant genes .  DOI:  10.1111/j.1365-313X.2009.04015.x ;  PMID:  19737364
• OsIRO2 is responsible for iron utilization in rice and improves growth and yield in calcareous soil .  DOI:  10.1007/s11103-011-9752-6 ;  PMID:  21331630
• A transcription factor OsbHLH156 regulates Strategy II iron acquisition through localising IRO2 to the nucleus in rice .  DOI:  10.1111/nph.16232 ;  PMID:  31574173
• Enhancement of Iron Acquisition in Rice by the Mugineic Acid Synthase Gene With Ferric Iron Reductase Gene and OsIRO2 Confers Tolerance in Submerged and Nonsubmerged Calcareous Soils .  DOI:  10.3389/fpls.2019.01179 ;  PMID:  31681346
• OsIRO3 negatively regulates Fe homeostasis by repressing the expression of OsIRO2 .  DOI:  10.1111/tpj.15864 ;  PMID:  35689518

Related News:

Gene Resources:

• NCBI ID: AK073385
• UniProt accessions:

Sequences: