Molecular Bases for the Regulation of Adventitious Root Generation in Plants

Abstract

The formation of adventitious roots (ARs) is an ecologically and economically important developmental process in plants. The evolution of AR systems is an important way for plants to cope with various environmental stresses. This review focuses on identified genes that have known to regulate the induction and initiation of ARs and offers an analysis of this process at the molecular level. The critical genes involved in adventitious rooting are the auxin signaling-responsive genes, including the AUXIN RESPONSE FACTOR (ARF) and the LATERAL ORGAN BOUNDARIES-DOMAIN (LOB) gene families, and genes associated with auxin transport and homeostasis, the quiescent center (QC) maintenance, and the root apical meristem (RAM) initiation. Several genes involved in cell wall modulation are also known to be involved in the regulation of adventitious rooting. Furthermore, the molecular processes that play roles in the ethylene, cytokinin, and jasmonic acid signaling pathways and their crosstalk modulate the generation of ARs. The crosstalk and interaction among many molecular processes generates complex networks that regulate AR generation.

Paradoxes of Plant Epigenetics

“…It is caused by the ability of plant cells to change their identity in response to signals from surrounding cells, physiological signals, and signals from the environment. This ability, that was discovered in the studies with chimeric plants (Poethig, 1989;Irish, 1991;Szymkowiak and Sussex, 1996) and in experiments on de novo regeneration of roots (reviews Xu, 2018;Li, 2021) and shoots (Shin et al, 2020;Lardon and Geelen, 2020) from various organs indicates that plant cells easily change the genetic program of development.…”

Understanding the Intricate Web of Phytohormone Signalling in Modulating Root System Architecture

“…Other members of the same transporter are found to transport IBA [ 132 , 133 ], which has been tested to have the highest ability to induce adventitious rooting [ 134 ]. Other hormones such as ethylene have been shown to regulate the positioning of AR primordia [ 135 ]. In the fern, Ceratopteris richardii , an intermediate clade WOX (IC-WOX) gene, CrWOXA , which is exclusively expressed in root founder cells during LR and AR initiation, regulates AR organogenesis.…”

“…In tomato, zeatin levels increased during AR induction and extension, which was reduced after IAA treatment [ 141 ]. CK also negatively affect PIN, YUCCA6 and LAX3 expression, leading to reduced auxin flow and hence, AR repression ( Figure 4 ) [ 135 ]. Transcriptomic studies dealing with poplar softwood cuttings revealed that PtARRs were significantly downregulated during a time course of 6 h that was concomitant with an increase in auxin signalling genes, depicting a general antagonism between auxin and CK during AR induction [ 142 ].…”

Synergism and antagonism in plant acclimation to abiotic stress combinations

“…A suitable example is the control of root architecture for optimized nutrient foraging under the impact of single or combinatorial stresses (Li 2021, Kumar et al 2020. The effect of hormones on root patterning differs among species and genotypes (Ristova et al 2018).…”