Adventitious Roots and Lateral Roots: Similarities and Differences

Abstract

In addition to its role in water and nutrient uptake, the root system is fundamentally important because it anchors a plant to its substrate. Although a wide variety of root systems exist across different species, all plants have a primary root (derived from an embryonic radicle) and different types of lateral roots. Adventitious roots, by comparison, display the same functions as lateral roots but develop from aerial tissues. In addition, they not only develop as an adaptive response to various stresses, such as wounding or flooding, but also are a key limiting component of vegetative propagation. Lateral and adventitious roots share key elements of the genetic and hormonal regulatory networks but are subject to different regulatory mechanisms. In this review, we discuss the developmental processes that give rise to lateral and adventitious roots and highlight knowledge acquired over the past few years about the mechanisms that regulate adventitious root formation.

Regulation of Hormonal Control, Cell Reprogramming, and Patterning during De Novo Root Organogenesis

“…roots from leaves) without exogenous supplementation of hormones (Bellini et al, 2014). Making roots de novo requires generating the different tissues and cell types of the new organ.…”

A Co-Opted Hormonal Cascade Activates Dormant Adventitious Root Primordia upon Flooding in Solanum dulcamara

“…Although AR primordia do not necessarily originate from the pericycle as lateral root (LR) primordia do, on the molecular and physiological level, initiation of AR and LR primordia show considerable similarity, with auxin taking a central role in both cases (Bellini et al, 2014). Mutants defective in the initiation of ARs have been identified in rice and maize (Zea mays; Inukai et al, 2001;Taramino et al, 2007;Kitomi et al, 2011), and the underlying genes of crown rootless1/adventitious rootless1 (CRL1/ARL1; in rice) and rootless concerning crown and seminal roots (RTCS; in maize) were shown to encode orthologous members of the LATERAL ORGAN BOUNDARIES DOMAIN/ASYMMETRIC LEAVES2-LIKE (LBD/ASL) protein family involved in LR initiation in Arabidopsis (Arabidopsis thaliana; Kitomi et al, 2011;Liu et al, 2005).…”

Branching Out in Roots: Uncovering Form, Function, and Regulation

“…4). This adaptive mechanism involves suppressing lateral root initiation on the dry side of a root Bellini et al (2014) and formatting based on Hochholdinger et al (2004b). The original description of the mutant phenotypes detailed in the table can be found in: Boerjan et al (1995), Delarue et al (1998), Fukaki et al (2002), Sorin et al (2005), Sibout et al (2006), Dello Ioio et al (2007), and Negi et al (2010 …”

“…Both are regulated by nutrient and hormonal signals (Bellini et al, 2014;Giehl and von Wirén, 2014), which act locally to induce or inhibit root branching. The net effect of these adaptive responses is to increase the surface area of the plant root system in the most important region of the soil matrix for resource capture (e.g.…”

“…Due to space limits, we cannot provide an exhaustive review of this subject area, focusing instead on recent research advances. However, we direct readers to several recent in-depth reviews on lateral root (Lavenus et al, 2013;Orman-Ligeza et al, 2013) and adventitious root development (Bellini et al, 2014).…”