Stem cells: Engines of plant growth and development

Authors: HONG, LIU - University Of California Berkeley; Fletcher, Jennifer

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2023
Publication Date: 10/4/2023
Citation: Hong, L., Fletcher, J.C. 2023. Stem cells: Engines of plant growth and development. International Journal of Molecular Sciences. 24(19). Article 14889. https://doi.org/10.3390/ijms241914889.
DOI: https://doi.org/10.3390/ijms241914889

Interpretive Summary: Plants, unlike animals, continually grow and form organs such as leaves and flowers throughout their lifetime. This lifelong growth pattern is dependent on the activity of stem cells in the shoot and root tips. Here we review the evidence that plant stem cell populations are established and maintained by overlapping networks of protein and hormone signaling pathways. Key genes in these stem cell signaling pathways have been selected during plant domestication to increase yield, and currently are being targeted to accelerate the domestication of new crop species as well as to improve plant regeneration processes.

Technical Abstract: The development of both animals and plants relies on populations of pluripotent stem cells that provide the cellular raw materials for organ and tissue formation. Plant stem cell reservoirs are housed at the shoot and root tips in structures called meristems, with the shoot apical meristem (SAM) producing all the aerial leaf, stem and flower organs throughout the life cycle. The SAM thus acts as the engine of plant development, and has unique structural and molecular features that allows it to balance self-renewal with differentiation and act as a constant source of new cells for organogenesis while simultaneously maintaining a stem cell reservoir for future organ formation. Studies have identified key roles for intercellular regulatory networks that establish and maintain meristem activity, including the KNOX transcription factor pathway and the CLV-WUS stem cell feedback loop. In addition, the plant hormones cytokinin and auxin act through their downstream signaling pathways in the SAM to promote stem cell activity and direct organ initiation. This review discusses how the various regulatory pathways collectively orchestrate SAM function and touches on how their manipulation can alter stem cell activity to improve crop yield.