Article

Multiple Facets of Arabidopsis Seedling Development Require * Indole-3-Butyric Acid-Derived Auxin

Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005, USA.
The Plant Cell (Impact Factor: 9.34). 03/2011; 23(3):984-99. DOI: 10.1105/tpc.111.083071
Source: PubMed

ABSTRACT

Levels of auxin, which regulates both cell division and cell elongation in plant development, are controlled by synthesis, inactivation, transport, and the use of storage forms. However, the specific contributions of various inputs to the active auxin pool are not well understood. One auxin precursor is indole-3-butyric acid (IBA), which undergoes peroxisomal β-oxidation to release free indole-3-acetic acid (IAA). We identified ENOYL-COA HYDRATASE2 (ECH2) as an enzyme required for IBA response. Combining the ech2 mutant with previously identified iba response mutants resulted in enhanced IBA resistance, diverse auxin-related developmental defects, decreased auxin-responsive reporter activity in both untreated and auxin-treated seedlings, and decreased free IAA levels. The decreased auxin levels and responsiveness, along with the associated developmental defects, uncover previously unappreciated roles for IBA-derived IAA during seedling development, establish IBA as an important auxin precursor, and suggest that IBA-to-IAA conversion contributes to the positive feedback that maintains root auxin levels.

Download full-text

Full-text

Available from: Rebekah A Rampey
    • "Similarly, the conversion of IBA to IAA (the principal form of auxin) occurs in peroxisomes. The predicted pathway for IBA metabolism also parallels with β-oxidation of fatty acids (Strader et al., 2011). Since, most of developmental changes as well as abiotic/biotic stresses are associated with modulation of cellular energetics and hormone levels, underlying signaling are either directly or indirectly integrated with redox-regulatory metabolic network. "

    No preview · Article · Feb 2016 · Advances in Agronomy
  • Source
    • "short root hair (Spiess et al., 2014) mes17 ill2 iar3, mes17 ibr3 not so severe shortroot hair phenotype (Spiess et al., 2014) Iar4 short root hairs. Rescued by oxYUCCA1 (Quint et al., 2009) YUCCA1ox long root hair phenotype (Zhao et al., 2001yucca1 yucca2 yucca4 yucca6 hairy root hair phenotype (Chen and Xiong, 2009)IBA-transport cdcg36(pen3,pdr8) long root hairs (Strader et al., 2011)IAA-perception tir1, tir1 afb2 afb3 short root hairs (Dharmasiri et al., 2005) pEXP7a:TIR1 longer root hairs (Ganguly et al., 2010) "
    [Show abstract] [Hide abstract]
    ABSTRACT: Auxin is a crucial growth regulator in plants. However, a comprehensive understanding of how auxin induces cell expansion is perplexing, because auxin acts in a concentration- and cell-type dependent manner. Consequently, it is desirable to focus on certain cell types to exemplify the underlying growth mechanisms. On the other hand, plant tissues display supracellular growth (beyond the level of single cells) and, hence, other cell types might compromise the growth of a certain tissue. Tip-growing cells do not display neighbour-induced growth constrains and, therefore, are a valuable source of information for growth controlling mechanisms. Here we focus on auxin-induced cellular elongation in root hairs, exposing a mechanistic view of plant growth regulation. We highlight a complex interplay between auxin metabolism and transport, steering root hair development in response to internal and external triggers. Auxin signalling modules and downstream cascades of transcription factors define a developmental program, which appears rate-limiting for cellular growth. With this knowledge in mind, the root hair cell is a very suitable model system to dissect cellular effectors required for cellular expansion.
    Preview · Article · Jan 2016 · Plant physiology
    • "Additionally, while the frequency of the oscillation in DR5 expression was unperturbed, the amplitude of the oscillation was diminished. Following disruption of auxin biosynthesis in roots with mutations in[5], similar alterations in the amplitude of the DR5 oscillation were observed. Based on the reduction in prebranch site and LR numbers observed in roots with decreased amplitude of the DR5 oscillation, the authors conclude that both aspects of the oscillation, frequency and amplitude, are necessary for LR pre-patterning. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Plasticity in plant form is achieved through differential elaboration of developmental pre-patterns during postembryonic organ development. A new report links the output of the root clock, an oscillatory transcriptional pre-patterning mechanism, with cell-type-specific production of the plant hormone auxin, and identifies a downstream component required for elaboration of the pre-pattern. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Jun 2015 · Current biology: CB
Show more