Supplemental Fig. 1 BiFC identification of the CDKG2/RCY1 interaction in the transiently transformed Arabidopsis mesophyll protoplasts.Protoplasts transformed with YNE-CDKG2/YCE (M) and YNE/YCE (M)-RCY1 represented the negative control.Bars =10 m.

Supplemental Fig. 2Yeast cells constitutively expressing CDKG2 are sensitive to salinity stress. Spot assay of theW303-1a yeast strain transformed with empty vector (pYES2/NTC) or CDKG2. Serial ten-fold dilutions were spotted on SC agar plates containing 0, 300 or 700 mM NaCl and cultured at 30°C for 48 hbefore photographing.

Supplemental Fig. 3 Phenotypes of the cdkg2mutants and CDKG2overexpression plants under salinity conditions.a, c Seedlings of Col-0 and cdkg2mutants (a) and VC and OE plants (c) were grown for 11 days under normal conditions (control), 100 mM or 150 mM NaCl before photographing.b, dComparison of root length between Col-0 and cdkg2mutants (b) and VC and OE plants (d) under different concentration of NaCl. The VC plants are a transgenic line carrying an empty vector.OE plants are transgenic lines constitutively expressing CDKG2.Data are expressed as mean values±SE. The double asterisks represent significant difference determined by the Student’s t-test at P < 0.01.

Supplemental Fig. 4 The ratio of Na+/K+and proline content in the tissue of wild type and cdkg2mutants.aNa+/K+ratio in the dry seeds or seeds germinated for 48 h under control (H2O) and 150 mM NaCl. Less Na+/K+ratio was found in cdkg2mutants than that in Col-0. b The proline content of wild type and cdkg2mutants in the dry seeds, imbibed seeds and germinated seeds. Data are expressed as mean values±SD.

Supplemental Fig. 5Transcript abundance of genes associated with flowering time under the salinity stress conditions in A. thaliana. Col-0 and cdkg2 mutants were grown under normal conditions for two weeks, followed by two irrigations with 200 mM NaCl. After floral bud formation, seedlings were harvested for RNA isolation. Transcript levels relative to that of AtActin2are presented. The relative expression levels of Col-0 under normal conditions were set at 1.0. Error bars represent mean±SD from threetechnicalreplicates. The experiment was repeated once with similar results.

Supplementary Table 1. Sequences of PCR primers used

Experiment / Primer name / Primers (5’-3’)
T-DNA identification / CDKG2-1-LP / CCAACACGGCATATATCATCC
CDKG2-2-RP / ATACCAGAAAGGAGACGTGGC
CDKG2-2-LP / CCAACACGGCATATATCATCC
CDKG2-2-RP / TCCAAGGCAGTCACAAAACTC
LBb1.3 / ATTTTGCCGATTTCGGAAC
Over-expression / CDKG2-OE-F / AAGGATCCATGGCGGCTGGGAGGAAT
CDKG2-OE-R / CCGAGCTCTCAGCCAAACAGACCGCC
Subcellular localization / CDKG2-GFP-F / AAGGATCCATGGCGGCTGGGAGGAAT
CDKG2-GFP-R / AAGTCGACGCCAAACAGACCGCCAGAC
GUS staining / CDKG2-GUS-F / AAAAGCTTGCCAACTATCCGCACTTTAAT
CDKG2-GUS-R / AAGGATCCCATACAGAACTTCGGTGAGAAAG
BiFC / RCY1-F / AAAGGATCCATGATTTACACTGCTATCGACAATTT
RCY1-R / AAACCCGGGATGGTGCCTACGACGGTCTT
RT-PCR / CDKG2-RT-F / ATTGTTCAATGGGAAAACGG
CDKG2-RT-R / TTCACAAATCACCACGGACC
Real-time PCR / LFY-QF / CGGCTTAGATTATCTGTTCCACTTG
LFY-QR / ACTCGCTCCTGATTTCTTCGC
FT-QF / GAGACCCTCTTATAGTAAGCA
FT-QR / CTTCCTCCGCAGCCACTCA
FLD-QF / TGCGGGAGAAGCTGCTCATAA
FLD-QR / GCCTTTGCAGATTGAGCCATG
FCA-QF / GAACTGGACAGCAGCAAGGCTGTTG
FCA-QR / TAGGGTGCCTATGCGTTCTCTCTCC
LD-QF / CAACTAATCCTGGAATGAGTGG
LD-QR / GGTTGTTGAGATTGGTTGTTGT
FY-QF / GATGCCTGGATCAATGGGAATG
FY-QR / TGCTGCTGTTGGAAAGGGTTGT
FLK-QF / CCACCAATGGTCGCTCAGCAAG
FLF-QR / ATCCGTAGCGTATCCTCCAGGCG
FVE-QF / TCTCCTCAAGCAACGACACC
FVE-QR / TGCGTTTTCTTCCCACTTTCT
FPA-QF / CCACCAGCAGATAAGGCAAA
FPA-QR / GTACCCTGACCATCCCCAGA
FLC-QF / CTAGCCAGATGGAGAATAATCATCATG
FLC-QR / TTAAGGTGGCTAATTAAGTAGTGGGAG
SOC1-QF / AGCTGCAGAAAACGAGAAGCTCTCTG
SOC1-QR / GGGCTACTCTCTTCATCACCTCTTCC
AP1-QF / CATGGGTGGTCTGTATCAAGAAGAT
AP1-QR / CATGCGGCGAAGCAGCCAAGGTT
Actin2-QF / GGTAACATTGTGCTCAGTGGTGG
Actin2-QR / AACGACCTTAATCTTCATGCTGC

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