PLETHORA gradient formation mechanism separates auxin responses

By Ari Pekka Mähönen, K. T. Tusscher, Riccardo Siligato, Ondřej Smetana, Sara Díaz-Triviño, J. Salojärvi, Guy Wachsman, Kalika Prasad, R. Heidstra, Ben Scheres. Nature, 2014

374 citations recorded by the source corpus.

During plant growth, dividing cells in meristems must coordinate transitions from division to expansion and differentiation, thus generating three distinct developmental zones: the meristem, elongation zone and differentiation zone. Simultaneously, plants display tropisms, rapid adjustments of their direction of growth to adapt to environmental conditions. It is unclear how stable zonation is maintained during transient adjustments in growth direction. In Arabidopsis roots, many aspects of zonation are controlled by the phytohormone auxin and auxin-induced PLETHORA (PLT) transcription factors, both of which display a graded distribution with a maximum near the root tip. In addition, auxin is also pivotal for tropic responses. Here, using an iterative experimental and computational approach, we show how an interplay between auxin and PLTs controls zonation and gravitropism. We find that the PLT gradient is not a direct, proportionate readout of the auxin gradient. Rather, prolonged high auxin levels generate a narrow PLT transcription domain from which a gradient of PLT protein is subsequently generated through slow growth dilution and cell-to-cell movement. The resulting PLT levels define the location of developmental zones. In addition to slowly promoting PLT transcription, auxin also rapidly influences division, expansion and differentiation rates. We demonstrate how this specific regulatory design in which auxin cooperates with PLTs through different mechanisms and on different timescales enables both the fast tropic environmental responses and stable zonation dynamics necessary for coordinated cell differentiation.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/8b6c70d526527e2b02b21a6acae52719f8b373ea

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Citations in the corpus

Implications of Abscisic Acid in the Drought Stress Tolerance of Plants (2020, background): “The transcriptional gradient of PLT1 and PLT2 is highly correlated with the auxin gradient in the root meristem [200,202].”