Figure 1. Cold‐induced OST1 kinase activity is independent of ABA and ABA receptors.

• A, B
  In‐gel kinase assay of OST1 activity in ABA receptor mutants under cold stress. Ten‐day‐old wild‐type, ost1‐3, pyr1 pyl1,4, pyr1 pyl1,2,4, pyr1 pyl4,5,8 and pyr1 pyl1,4,5,8 mutants were treated at 4°C for 2 h. Total protein extracts were prepared and separated on SDS–PAGE gel containing 0.1 mg/ml GST‐∆ABF2 as a substrate, and incubated with 60 μCi of [γ‐³²P]ATP. Representative pictures are shown in (A), and relative kinase activity is shown in (B).
• C, D
  In‐gel kinase assay of OST1 activity in ABI1‐OE14 and abi1 abi2hab1 mutants under cold stress. Representative pictures are shown in (C), and relative kinase activity is shown in (D).

Data information: In (A and C), Top, gel autoradiograph; bottom, Coomassie Brilliant Blue (CBB) staining of RuBisCO large subunit was used as a loading control. The ratio of band intensity of OST1 to RuBisCO in the wild type with cold treatment for 2 h was set to 1.00. In (B and D), each bar represents the mean ± SEM of three biological repeats. *P < 0.05 (two‐tailed t‐test).Source data are available online for this figure.