Marhava, P. and Bassukas, A. E. L. and Zourelidou, M. and Kolb, M. and Moret, B. and Fastner, A. and Schulze, W. X. and Cattaneo, P. and Hammes, U. Z. and Schwechheimer, C. and Hardtke, C. S. (2018) A molecular rheostat adjusts auxin flux to promote root protophloem differentiation. NATURE, 558 (7709). 297-+. ISSN 0028-0836, 1476-4687
Full text not available from this repository. (Request a copy)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 niche(2-4). 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 differentiate(5,6). 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 plasmamembrane-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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PLASMA-MEMBRANE; ARABIDOPSIS-THALIANA; DEPENDENT GROWTH; TRANSPORT; EFFLUX; PROTEIN; PHOSPHORYLATION; ENDOCYTOSIS; GRADIENTS; FEEDBACK; |
| Subjects: | 500 Science > 580 Botanical sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Pflanzenwissenschaften > Lehrstuhl für Zellbiologie und Pflanzenphysiologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 09 Mar 2020 10:01 |
| Last Modified: | 09 Mar 2020 10:01 |
| URI: | https://pred.uni-regensburg.de/id/eprint/14403 |
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