Gene Details:

• MSU gene ID: LOC_Os01g63770
• RAPdb gene ID: Os01g0856500
• Gene Symbol: OsAUX1
• Genome: MSU7 ,  IRGSP-1.0
• Species: Oryza sativa

Functional Descriptions:

• The expression of an auxin transporter (OsAUX1) and a tillering inhibitor (OsTB1) were downregulated by overexpression of OsmiR393, which suggested that a gene chain from OsmiR393 to rice tillering may be from OsTIR1 and OsAFB2 to OsAUX1, which affected the transportation of auxin, then to OsTB1, which finally controlled tillering.
• OsAUX1 controls lateral root initiation in rice (Oryza sativa L.).
• The auxin influx carriers in Arabidopsis have been shown to control lateral root development and gravitropism, but little is known about these proteins in rice.
• Three OsAUX1 T-DNA insertion mutants and RNAi knockdown transgenic plants reduced lateral root initiation compared to WT plants.
• OsAUX1 overexpression plants exhibited increased lateral root initiation and OsAUX1 was highly expressed in lateral roots and lateral root primordia.
• Similarly, the auxin reporter, DR5-GUS, was expressed at lower levels in OsAUX1 than in the WT plants, which indicated that the auxin levels in the mutant roots had decreased.
• Overall, our results indicated that OsAUX1 was involved in polar auxin transport and functioned to control auxin-mediated lateral root initiation in rice.
• Polar auxin transport, mediated by influx and efflux transporters, controls many aspects of plant growth and development.
• Exogenous NAA treatment rescued the defective phenotype in OsAUX1-1 plants, whereas IAA and 2,4-D could not, which suggested that OsAUX1 was a putative auxin influx carrier.
• The transcript levels of several auxin-signaling genes and cell cycle genes significantly declined in OsAUX1, hinting that the regulatory role of OsAUX1 may be mediated by auxin-signaling and cell cycle genes.
• OsAUX1 expression in root hair cells is different from its paralogous gene, AtAUX1, expressed in non-hair cells.
• Taken together, our results indicate that OsAUX1 plays an important role in root development and in responses to Cd stress.
• However, OsAUX1 - like AtAUX1 - also localizes at the plasma membrane and seems to function as an auxin tranporter.
• Decreased auxin distribution and contents in OsAUX1 mutant result in reduction of OsCyCB1;1 expression and shortened PR, LR and RH under Cd stress, but can be rescued by the membrane-permeable auxin, 1-naphthaleneacetic acid (NAA).
• Here, we characterize rice OsAUX1 mutants that have longer PR and shorter RH in hydroponic culture, and that are more sensitive to Cd stress compared to WT/Dongjin (DJ).
• Cd contents in the OsAUX1 mutant were not altered but reactive oxygen species (ROS)-mediated damage was enhanced, further increasing the OsAUX1 mutant sensitivity to Cd stress.
• Moreover, protein localization of auxin transporters PIN1 homologs and GFP tagged OsAUX1 overlapped with DR5-VENUS during spikelet development, helping validate these auxin response reporters are reliable markers in rice.
• Rice auxin influx carrier OsAUX1 facilitates root hair elongation in response to low external phosphate.
• Here, we attempted to modify root angle in rice by disrupting the OsAUX1 auxin influx transporter gene in an effort to improve rice P acquisition efficiency.
• We show by X-ray microCT imaging that root angle is altered in the OsAUX1 mutant, causing preferential foraging in the top soil where P normally accumulates, yet surprisingly, P acquisition efficiency does not improve.
• Through closer investigation, we reveal that OsAUX1 also promotes root hair elongation in response to P limitation.
• We demonstrate that OsAUX1 functions to mobilize auxin from the root apex to the differentiation zone where this signal promotes hair elongation when roots encounter low external P.
• We conclude that auxin and OsAUX1 play key roles in promoting root foraging for P in rice.
• The WUSCHEL-related homeobox transcription factor OsWOX4 controls the primary root elongation by activating OsAUX1 in rice.

Function-related keywords:

• tillering ,  tiller ,  transporter ,  auxin ,  root ,  growth ,  iaa ,  cell-cycle ,  lateral-root ,  development ,  stress ,  plasma-membrane ,  root-development ,  root-hair ,  reactive-oxygen-species ,  spikelet ,  auxin-transport ,  auxin-response ,  spikelet-development ,  transcription-factor ,  root-elongation ,  primary-root

Literature:

• OsTIR1 and OsAFB2 downregulation via OsmiR393 overexpression leads to more tillers, early flowering and less tolerance to salt and drought in rice .  DOI:  10.1371/journal.pone.0030039 ;  PMID:  22253868
• Adenosine diphosphate ribosylation factor-GTPase-activating protein stimulates the transport of AUX1 endosome, which relies on actin cytoskeletal organization in rice root development .  DOI:  10.1111/j.1744-7909.2011.01059.x ;  PMID:  21631728
• OsAUX1 controls lateral root initiation in rice (Oryza sativa L.) .  DOI:  10.1111/pce.12467 ;  PMID:  25311360
• The auxin transporter, OsAUX1, is involved in primary root and root hair elongation and in Cd stress responses in rice (Oryza sativa L.) .  DOI:  10.1111/tpj.12929 ;  PMID:  26140668
• Dynamic Regulation of Auxin Response during Rice Development Revealed by Newly Established Hormone Biosensor Markers .  DOI:  10.3389/fpls.2017.00256 ;  PMID:  28326089
• Rice auxin influx carrier OsAUX1 facilitates root hair elongation in response to low external phosphate .  DOI:  10.1038/s41467-018-03850-4 ;  PMID:  29650967
• The WUSCHEL-related homeobox transcription factor OsWOX4 controls the primary root elongation by activating OsAUX1 in rice .  DOI:  10.1016/j.plantsci.2020.110575 ;  PMID:  32771139
• MiR529a controls plant height, tiller number, panicle architecture and grain size by regulating SPL target genes in rice (Oryza sativa L.) .  DOI:  10.1016/j.plantsci.2020.110728 ;  PMID:  33288029
• The Potassium Transporter OsHAK5 Alters Rice Architecture via ATP-Dependent Transmembrane Auxin Fluxes .  DOI:  10.1016/j.xplc.2020.100052 ;  PMID:  33367257

Related News:

Gene Resources:

• NCBI ID:
• UniProt accessions:

Sequences: