Molecular Mechanisms of Adventitious Root Formation

Adventitious root formation constitutes a de novo organogenesis process whereby new roots emerge from non-root tissues such as stems, leaves or hypocotyls. At its core, this process is regulated by an intricate network of phytohormones—chiefly the auxins—whose distribution, synthesis and signalling coordinates the acquisition of competence, induction of founder cells and subsequent root primordium development. Polar auxin transport establishes local concentration maxima that trigger transcriptional reprogramming via Auxin Response Factors, AUX/IAA inhibitory proteins and downstream transcription factors of the LBD, WOX and ERF families. Concomitant cross-talk with ethylene, jasmonates, cytokinins and reactive oxygen and nitrogen species modulates phase transitions from cell division to differentiation. Omics studies have exposed myriad regulators of hormone homeostasis, signal transduction, endosomal trafficking and epigenetic modification that integrate environmental cues—such as wounding or flooding—with intrinsic developmental programmes. Advances in quantitative genomics, genome-wide association studies and functional screens have begun to unravel the polygenic nature of rooting capacity and its variation among species, paving the way for targeted improvement of clonal propagation and stress resilience in crops and forestry species.

Research from Nature Portfolio

Recent studies have elucidated a direct regulatory module linking auxin-responsive transcription factors to a key organ-forming regulator in trees. Work employing a heterologous poplar model demonstrated that two members of the Auxin Response Factor family bind to the promoter of a BABY BOOM transcription factor, enhancing its expression in response to exogenous indole-3-acetic acid. Overexpression of these ARFs in poplar significantly increased adventitious root initiation and outgrowth. The research further uncovered a novel interaction between one ARF and an RNA helicase, suggesting that post-transcriptional mechanisms cooperate with transcriptional activation to fine-tune root-forming programmes under auxin stimuli.

Molecular Mechanisms of Adventitious Root Formation publication trend

The graph below shows the total number of articles in molecular mechanisms of adventitious root formation across all publications each year (not limited to Nature Index journals).

Technical terms

Adventitious root: A root arising from non-root tissues, enabling vegetative propagation and stress adaptation.

Auxin Response Factor (ARF): A transcription factor that binds auxin response elements to modulate gene expression in response to auxin.

Expression quantitative trait loci (eQTL): Genomic regions that explain variation in gene expression levels across individuals.

Genome-wide association study (GWAS): A population-scale analysis linking genetic variants to phenotypic traits, such as rooting efficiency.

Reactive oxygen species (ROS): Signal molecules including hydrogen peroxide that influence hormone signalling and cell differentiation during root induction.

References

1. Expression quantitative trait loci mapping identified PtrXB38 as a key hub gene in adventitious root development in Populus. New Phytologist (2023).
2. GWAS identifies candidate genes controlling adventitious rooting in Populus trichocarpa. Horticulture Research (2023).
3. Adventitious Root Formation in Plants: The Implication of Hydrogen Peroxide and Nitric Oxide †. Antioxidants (2023).
4. LkARF7 and LkARF19 overexpression promote adventitious root formation in a heterologous poplar model by positively regulating LkBBM1. Communications Biology (2023).
5. Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings. Frontiers in Plant Science (2016).