15 mayo 2020

Nutrient dose-responsive transcriptome changes driven by Michaelis-Menten kinetics underlie plant growth rates.

DOI : 10.1073/pnas.1918619117

José Miguel Álvarez

An increase in nutrient dose leads to proportional increases in crop biomass and

agricultural yield. However, the molecular underpinnings of this nutrient

dose-response are largely unknown. To investigate, we assayed changes in the

Arabidopsis root transcriptome to different doses of nitrogen (N)-a key plant

nutrient-as a function of time. By these means, we found that rate changes of

genome-wide transcript levels in response to N-dose could be explained by a

simple kinetic principle: the Michaelis-Menten (MM) model. Fitting the MM model

allowed us to estimate the maximum rate of transcript change (V max), as well as

the N-dose at which one-half of V max was achieved (K m) for 1,153

N-dose-responsive genes. Since transcription factors (TFs) can act in part as

the catalytic agents that determine the rates of transcript change, we

investigated their role in regulating N-dose-responsive MM-modeled genes. We

found that altering the abundance of TGA1, an early N-responsive TF, perturbed

the maximum rates of N-dose transcriptomic responses (V max), K m, as well as

the rate of N-dose-responsive plant growth. We experimentally validated that

MM-modeled N-dose-responsive genes included both direct and indirect TGA1

targets, using a root cell TF assay to detect TF binding and/or TF regulation

genome-wide. Taken together, our results support a molecular mechanism of

transcriptional control that allows an increase in N-dose to lead to a

proportional change in the rate of genome-wide expression and plant growth.

Investigadores Participantes del Centro

Laboratorio de Regulación del Genoma Vegetal

Doctor en Ciencias Biológicas, Pontificia Universidad Católica de Chile



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