Auxin and cytokinin are key endogenous regulators of plant development. Although cytokinin-mediated modulation of auxin distribution is a developmentally crucial hormonal interaction, its molecular basis is largely unknown. Here we show a direct regulatory link between cytokinin signalling and the auxin transport machinery uncovering a mechanistic framework for cytokinin-auxin cross-talk. We show that the CYTOKININ RESPONSE FACTORS (CRFs), transcription factors downstream of cytokinin perception, transcriptionally control genes encoding PIN-FORMED (PIN) auxin transporters at a specific PIN CYTOKININ RESPONSE ELEMENT (PCRE) domain. Removal of this cis-regulatory element effectively uncouples PIN transcription from the CRF-mediated cytokinin regulation and attenuates plant cytokinin sensitivity. We propose that CRFs represent a missing cross-talk component that fine-tunes auxin transport capacity downstream of cytokinin signalling to control plant development.
- MeSH
- Arabidopsis MeSH
- chromatinová imunoprecipitace MeSH
- cytokininy metabolismus MeSH
- geneticky modifikované rostliny MeSH
- konfokální mikroskopie MeSH
- kořeny rostlin metabolismus MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- kyseliny indoloctové metabolismus MeSH
- membránové transportní proteiny genetika metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- responzivní elementy MeSH
- signální transdukce MeSH
- transkripční faktory genetika metabolismus MeSH
- zelené fluorescenční proteiny MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Plant architecture is one of the key factors that affect plant survival and productivity. Plant body structure is established through the iterative initiation and outgrowth of lateral organs, which are derived from the shoot apical meristem and root apical meristem, after embryogenesis. Here we report that ADP1, a putative MATE (multidrug and toxic compound extrusion) transporter, plays an essential role in regulating lateral organ outgrowth, and thus in maintaining normal architecture of Arabidopsis. Elevated expression levels of ADP1 resulted in accelerated plant growth rate, and increased the numbers of axillary branches and flowers. Our molecular and genetic evidence demonstrated that the phenotypes of plants over-expressing ADP1 were caused by reduction of local auxin levels in the meristematic regions. We further discovered that this reduction was probably due to decreased levels of auxin biosynthesis in the local meristematic regions based on the measured reduction in IAA levels and the gene expression data. Simultaneous inactivation of ADP1 and its three closest homologs led to growth retardation, relative reduction of lateral organ number and slightly elevated auxin level. Our results indicated that ADP1-mediated regulation of the local auxin level in meristematic regions is an essential determinant for plant architecture maintenance by restraining the outgrowth of lateral organs.
- MeSH
- Arabidopsis genetika růst a vývoj MeSH
- kořeny rostlin genetika růst a vývoj metabolismus MeSH
- květy genetika růst a vývoj MeSH
- kyseliny indoloctové metabolismus MeSH
- meristém růst a vývoj metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- proteiny přenášející organické kationty genetika MeSH
- regulace genové exprese u rostlin MeSH
- výhonky rostlin genetika růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
