Rho GTPase Signaling in Plant Growth Dynamics

Rho GTPases are pivotal signal transducers that govern dynamic plant cell growth through the regulation of cytoskeleton organisation, membrane traffic and cell wall deposition. In plants, the Rho-of-Plants (ROP) family operates as binary molecular switches, cycling between GTP-bound active and GDP-bound inactive states, to direct processes including pollen tube and root hair tip growth, formation of specialised cell wall patterns in xylem vessels, and differential cell expansion in response to environmental and hormonal stimuli. This spatio-temporal control is mediated by guanine nucleotide exchange factors (GEFs), which catalyse ROP activation, and GTPase-activating proteins (GAPs), which promote inactivation. Signal integration from auxin, abscisic acid and mechanical forces leads to the formation of nanometre-scale signalling clusters at the plasma membrane, orchestrating cytoskeletal rearrangement and exocytosis. Recent advances further reveal a reaction–diffusion mechanism underlying ROP domain self-organisation as well as ROP effector roles in hormonal crosstalk and stem cell niche maintenance. Insights into Rho GTPase signalling not only advance our understanding of plant morphogenesis but also inform strategies for crop improvement and enhanced stress resilience.

Research from Nature Portfolio

Recent studies have delineated two subtypes of ROP GTPase-activating proteins that assemble into distinct membrane domains to modulate tip growth and cell width in moss. One class of GAPs clusters active ROPs to constrain domain size, while the other rapidly inactivates ROPs, together ensuring balanced polar expansion. Parallel investigations in Arabidopsis leaf pavement cells demonstrate that auxin triggers sterol-dependent nanoclustering of receptor kinases, which stabilises membrane domains and promotes ROP6 activation. This nanoclustering is integral to cortical microtubule organisation and engenders a positive feedback loop reinforcing cell polarity.

Rho GTPase Signaling in Plant Growth Dynamics publication trend

The graph below shows the total number of articles in rho gtpase signaling in plant growth dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Rho GTPase (ROP): A plant-specific small GTP-binding protein that functions as a molecular switch to regulate cytoskeletal and membrane dynamics.

Guanine nucleotide exchange factor (GEF): Protein that activates Rho GTPases by promoting the exchange of GDP for GTP.

GTPase-activating protein (GAP): Protein that inactivates Rho GTPases by stimulating their intrinsic GTP hydrolysis.

CRIB domain: A conserved motif in effector proteins that binds selectively to the active form of Rho GTPases.

Nanoclustering: The assembly of membrane proteins into discrete, nanometre-scale clusters that spatially organise signal transduction.

References

1. Two subtypes of GTPase-activating proteins coordinate tip growth and cell size regulation in Physcomitrium patens. Nature Communications (2023).
2. Auxin-induced signaling protein nanoclustering contributes to cell polarity formation. Nature Communications (2020).
3. Physcomitrium patens PpRIC, an ancestral CRIB-domain ROP effector, inhibits auxin-induced differentiation of apical initial cells. Cell Reports (2023).
4. Genetic analysis of GEFs and GDIs in rice reveals the roles of OsGEF5, OsGDI1, and OsGEF3 in the regulation of grain size and plant height. The Crop Journal (2023).
5. A Rho-based reaction-diffusion system governs cell wall patterning in metaxylem vessels. Scientific Reports (2018).