The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators

Abstract

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.

Wandering between hot and cold: temperature dose-dependent responses

“…Internal signals, such as plant hormones (e.g. auxin [4,5] and brassinosteroids [6]), transcriptional co-activators (e.g. ANGUSTIFOLIA3 [7]), and small RNAs [8,9], have been shown to generate a specific output depending on the concentration.…”

Genome wide association analysis of root hair traits in rice reveals novel genomic regions controlling epidermal cell differentiation

“…A single gene, LOC_Os08g12820, a proteasome/cyclosome repeat containing protein, was significant in the gene-level analysis, is expressed in both cells and hairs, and contains a cis-acting RHE in its putative promoter region. The Arabidopsis ortholog of this gene, AT2G32730, RPN2a, is differentially phosphorylated under auxin application, indicating a possible role in root hair growth [ 85 ]. This suggests that LOC_Os08g12820 warrants further investigation into its role in root hair growth.…”

The role of indole derivative in the growth of plants: A review

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