A molecular rheostat adjusts auxin flux to promote root protophloem differentiation

P. Marhava, A. E. L. Bassukas, M. Zourelidou, M. Kolb, B. Moret, A. Fastner, W. X. Schulze, P. Cattaneo, U. Z. Hammes, C. Schwechheimer () and C. S. Hardtke ()
Additional contact information
P. Marhava: University of Lausanne
A. E. L. Bassukas: Technical University of Munich
M. Zourelidou: Technical University of Munich
M. Kolb: Technical University of Munich
B. Moret: University of Lausanne
A. Fastner: Regensburg University
W. X. Schulze: University of Hohenheim
P. Cattaneo: University of Lausanne
U. Z. Hammes: Technical University of Munich
C. Schwechheimer: Technical University of Munich
C. S. Hardtke: University of Lausanne

Nature, 2018, vol. 558, issue 7709, 297-300

Abstract: Abstract Auxin influences plant development through several distinct concentration-dependent effects 1 . In the Arabidopsis root tip, polar auxin transport by PIN-FORMED (PIN) proteins creates a local auxin accumulation that is required for the maintenance of the stem-cell niche2–4. Proximally, stem-cell daughter cells divide repeatedly before they eventually differentiate. This developmental gradient is accompanied by a gradual decrease in auxin levels as cells divide, and subsequently by a gradual increase as the cells differentiate5,6. However, the timing of differentiation is not uniform across cell files. For instance, developing protophloem sieve elements (PPSEs) differentiate as neighbouring cells still divide. Here we show that PPSE differentiation involves local steepening of the post-meristematic auxin gradient. BREVIS RADIX (BRX) and PROTEIN KINASE ASSOCIATED WITH BRX (PAX) are interacting plasma-membrane-associated, polarly localized proteins that co-localize with PIN proteins at the rootward end of developing PPSEs. Both brx and pax mutants display impaired PPSE differentiation. Similar to other AGC-family kinases, PAX activates PIN-mediated auxin efflux, whereas BRX strongly dampens this stimulation. Efficient BRX plasma-membrane localization depends on PAX, but auxin negatively regulates BRX plasma-membrane association and promotes PAX activity. Thus, our data support a model in which BRX and PAX are elements of a molecular rheostat that modulates auxin flux through developing PPSEs, thereby timing PPSE differentiation.

Date: 2018
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41586-018-0186-z Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:558:y:2018:i:7709:d:10.1038_s41586-018-0186-z

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-018-0186-z

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().