Figure 6.

N-Terminal Extensions in CAMKK4/5 Promote Stomatal Inhibition in the SPCH and MUTE Stages.

(A) Protein schematic (left) and images of phenotypes associated with expressing CAMKK5 in the SPCH, MUTE, and FAMA stages of stomatal development as indicated.

(B) to (D) The 10-DPG seedlings expressing CAMKK5∆N_ext in the SPCH (B), MUTE (C), and FAMA (D) stages show wild-type stomatal development patterns.

(E) to (G) The 10-DPG seedlings expressing CAMKK5∆N_int in the SPCH (E), MUTE (F), and FAMA (G) stages show wild-type stomatal development patterns. Thus, both N_ext and N_int have a positive function in inhibiting stomatal development but do not prevent CAMKK4/5 from inducing stomatal clustering in the FAMA stage.

(H) to (J) The 10-DPG seedlings expressing CAMKK5∆C_term in the SPCH (H), MUTE (I), and FAMA (J) stages show the same stomatal development patterns as controls (A).

The relative activity of each kinase variant in in vitro kinase assays is depicted as follows (+, less active than full length; ++, comparable activity to the full-length CAMKK). Hashed boxes in schematic representations of kinase variants indicate the region(s) that were removed. All images are of 10-DPG abaxial cotyledons, and bars = 25 μm.