Abstract
Auxin is involved in many aspects of root development and physiology, including the formation of lateral roots. Improving our understanding of how the auxin response is mediated at the protein level over time can aid in developing a more complete molecular framework of the process. This study evaluates the effects of exogenous auxin treatment on the Arabidopsis root proteome after exposure of young seedlings to auxin for 8, 12, and 24 h, a timeframe permitting the initiation and full maturation of individual lateral roots. Root protein extracts were processed to peptides, fractionated using off-line strong-cation exchange, and analyzed using ultra-performance liquid chromatography and data independent acquisition-based mass spectrometry. Protein abundances were then tabulated using label-free techniques and evaluated for significant changes. Approximately 2000 proteins were identified during the time course experiment, with the number of differences between the treated and control roots increasing over the 24 h time period, with more proteins found at higher abundance with exposure to auxin than at reduced abundance. Although the proteins identified and changing in levels at each time point represented similar biological processes, each time point represented a distinct snapshot of the response. Auxin coordinately regulates many physiological events in roots and does so by influencing the accumulation and loss of distinct proteins in a time-dependent manner. Data are available via ProteomeXchange with the identifier PXD001400.
Highlights
Auxin regulates many critical aspects of root development and physiology, including the response to gravity and light [1], the orientation and extent of cell division [2], and the initiation of lateral roots [3]
To compare the auxin response of the plant root proteome relative to that of the transcriptome, Arabidopsis Col-0 seedlings were grown in continuous light on agar plates for 5–6 d following germination and transferred to agar plates plus or minus 1 μM IAA for 8, 12, or 24 h in biological triplicate, identical to the procedure described for two recent transcriptomic analyses [13,14]
Under these conditions the auxin-treated seedlings exhibited the temporal inhibition of primary root elongation and increases in lateral root initiation as reported previously [13], where elongation was significantly different from controls at 30 min and lateral root initiation was statistically significant by 8 h
Summary
Auxin regulates many critical aspects of root development and physiology, including the response to gravity and light [1], the orientation and extent of cell division [2], and the initiation of lateral roots [3] These processes are controlled by the establishment and maintenance of distinct intracellular pools of auxin generated by cellular- and tissue-specific gradients of the hormone [2]. The present working model of lateral root formation consists of programed cell death processes in distal lateral root cap cells leading to the cyclical release of auxin The transport of this released auxin to pericycle cells leads to the conversion of a subset of these cells to lateral root primordia and subsequently lateral roots. The biochemistry of lateral root formation beyond these initial cell fate decisions suggests a suite of processes both inside (symplastic) and outside (apoplastic) the plasma membrane [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
