Table 1.
Steady-state currents of wild-type, pp2c.d2/5/6 triple mutant, PP2C.D5 and SAUR19/63 overexpression lines and saur56-1 saur60-2 double mutant fitted to a Boltzmann function
| Genotype | gmax (mS cm−2) | V 1/2 (mV) | δ |
|---|---|---|---|
| I K, out | |||
| Col 0 | 3.93 ± 0.05 (A) | –16 ± 1 (X) | 2.12 ± 0.08 |
| pp2c.d2/5/6 | 4.07 ± 0.03 (A) | –33 ± 1 (Y) | |
| PGC:PP2C.D5 | 3.49 ± 0.0(B) | –3 ± 1 (Z) | |
| StrepII-SAUR19 | 1.81 ± 0.03 (C) | –31 ± 2 (Y) | |
| SAUR63-YFP-HA | 1.98 ± 0.02 (C) | –42 ± 3 (Y) | |
| I K,in | |||
| Col-0 | 0.79 ± 0.06 (a) | –176 ± 2 | –1.47 ± 0.21 |
| pp2c.d2/5/6 | 0.19 ± 0.03 (b) | ||
| PGC:PP2C.D5 | 1.55 ± 0.10 (c) | ||
| StrepII-SAUR19 | 0.14 ± 0.03 (b) | ||
| SAUR63-YFP-HA | 0.00 ± 0.03 (d) | ||
|
I K, out | |||
| Col-0 | 3.98 ± 0.10 (I) | –15 ± 2 (x) | 2.12 ± 0.15 |
| saur56-1 saur60-2 | 5.33 ± 0.33 (J) | 5 ± 2 (y) | |
| I K,in | |||
| Col-0 | 0.91 ± 0.19 (i) | –179 ± 8 | –1.40 ± 0.24 |
| saur56-1 saur60-2 | 2.86 ± 0.62 (j) | ||
After instantaneous background current subtraction, steady-state currents were fitted to a Boltzmann function of the form IK = gmax* (V–EK)/(1+e δF(V–V1/2)/RT), where V1/2 is the voltage giving half-maximal activation of the current IK, δ is the voltage sensitivity coefficient, gmax is the maximum conductance, EK is the K+ equilibrium voltage, and R and T have their usual meanings. The data were adjusted to ensure the equivalents between Col-0 currents. Fittings for IK,out yielded common voltage-sensitivity coefficients (δ), and IK,in were fitted with common voltage-sensitivity coeficients (δ) and common midpoint voltage (V1/2). Different letters within each dataset indicate statistically significant differences determined by one-way analysis of variance Scheffe test (P < 0.05).