Lateral Root Inducible System in <em>Arabidopsis</em> and Maize

Abstract

Lateral root development contributes significantly to the root system, and hence is crucial for plant growth. The study of lateral root initiation is however tedious, because it occurs only in a few cells inside the root and in an unpredictable manner. To circumvent this problem, a Lateral Root Inducible System (LRIS) has been developed. By treating seedlings consecutively with an auxin transport inhibitor and a synthetic auxin, highly controlled lateral root initiation occurs synchronously in the primary root, allowing abundant sampling of a desired developmental stage. The LRIS has first been developed for Arabidopsis thaliana, but can be applied to other plants as well. Accordingly, it has been adapted for use in maize (Zea mays). A detailed overview of the different steps of the LRIS in both plants is given. The combination of this system with comparative transcriptomics made it possible to identify functional homologs of Arabidopsis lateral root initiation genes in other species as illustrated here for the CYCLIN B1;1 (CYCB1;1) cell cycle gene in maize. Finally, the principles that need to be taken into account when an LRIS is developed for other plant species are discussed.

Transcriptional Regulation of zma-MIR528a by Action of Nitrate and Auxin in Maize

“…On the other hand, NPA-treated seedlings subjected to a short pulse (6 h) of the auxin NAA did not show evident growth differences with respect to its control (NPA alone) and contrasted with H 2 O imbibition ( Figure 4 B bottom and Supplementary Material, Figure S4C ). However, extended incubation with NAA promoted the emergence of multiple lateral roots ( Supplementary Material, Figure S4D ), confirming the reported physiological effect of exogenous auxin [ 35 ].…”

“…Seeds were disinfected with 6% commercial NaClO solution under constant agitation (250 rpm) for about 5 min and rinsed five times with 100 mL of fresh sterilized water. Imbibition, vertical germination, and seedling establishment were performed as previously reported [ 35 ]. Briefly, seeds were placed in paper towel rolls and incubated vertically in cylindrical containers with a 12 h light/12 h dark photoperiod at 28 °C.…”

“…Rolls were soaked in 150 mL of either sterile water (control condition; mock) or 30 mM KNO 3 solution for 72 h, with sampling after 24, 48, and 72 h of continuous treatment. For exogenous auxin addition, experiments were performed as recommended by [ 35 ]. Seeds were imbibed for 72 h in water (mock) or 50 µM N-1-naphthylphthalamic acid (NPA, auxin transport inhibitor).…”

TOR senses and regulates spermidine metabolism during seedling establishment and growth in maize and Arabidopsis

“…For long-term seedling growth phenotyping and treatments, whole seeds were rolled in a paper towel and placed vertically in a cylindrical container under 16 h light/8 h darkness photoperiod at 28°C as described previously ( Crombez et al., 2016 ). The paper towel was imbibed in water (mock), 50 μM AZD-8055 (AZD), 0.1 mM (for non-germinated seeds) or 0.2 mM (for germinated seeds) Spermidine (Spd), or combination of both (Spd/AZD).…”

Cellular and gene expression patterns associated with root bifurcation in Selaginella

“…After a series of well-orchestrated divisions, a new root meristem is formed that grows out of the parent root. Interestingly, important insights into the anatomical development and molecular regulation of LR formation were obtained by employing LR inducible systems, allowing synchronous induction of many LRs (Himanen et al, 2002;Himanen et al, 2004;Vanneste et al, 2005;De Smet et al, 2008;De Rybel et al, 2010;Jansen et al, 2013;Xuan et al, 2015;Crombez et al, 2016;Herrbach et al, 2017).…”