Meristem Initiation and de novo Stem Cell Formation

Area of Science:

• Plant developmental biology
• Meristem regulation
• Stem cell biology

Background:

• Plant aerial architecture depends on meristem activity for axis development.
• Shoot apical meristems (SAM) establish the main stem, while axillary meristems (AMs) enable plant branching.
• AMs arise post-embryonically from leaf axil cells, organizing into SAM-like structures.

Purpose of the Study:

• To review recent findings on the de novo establishment of stem cell populations and regulatory niches in AMs.
• To highlight the importance of these processes for the indeterminate fate of AMs.
• To discuss the concept of 'premeristems' as a transient stage in stem cell formation.

Main Methods:

• Review of current scientific literature on plant meristem development.
• Analysis of regulatory networks involved in de novo stem cell formation.
• Comparative discussion of meristem formation processes.

Main Results:

• De novo stem cell formation for AMs is a progressive process, not instantaneous.
• A transient regulatory network, distinct from functional meristem networks, initiates stem cell formation.
• This transient stage is termed 'premeristems'.

Conclusions:

• The concept of premeristems offers a new perspective on the initiation of axillary meristems.
• Understanding this transient phase is key to comprehending plant branching and indeterminate growth.
• The premeristem concept may be applicable to the formation of other plant meristems.