Analysis of cngc19 and cngc20 T-DNA insertion lines. (A) Genomic organization of CNGC19 and CNGC20 and the respective T-DNA insertions for cngc19-1 (SALK line 027306) and cngc20-1 (SALK line 129133). Exons are shown in bold. (B) Absence of CNGC19 mRNA from cngc19-1 plants (lane 2), but presence in Col-0 (lane 1) and a backcrossed CNGC19 wild type (WT, lane 3). Upper traces: PCR result using CNGC19 gene-specific primers, which amplified a 348 bp fragment downstream of the T-DNA insertion, lower traces: Actin2 primers were used as a control. (C) Corresponding PCR analysis of the T-DNA insertion line cngc20-1 with cDNA from Col-0 (lane 1), cngc20-1 (lane 2) and a backcrossed CNGC20 wild type (WT, lane 3). CNGC20 gene-specific primers, which span a 310 bp fragment downstream of the T-DNA insertion, were used. No PCR fragment was amplified from cDNA from homozygous cngc20-1 (lane 2). (D) Unchanged root growth of cngc19-1 plants. Root length increase of cngc19-1 and wild type seedlings were measured during a 7-day growth period, starting 4 days after stratification. Mutant (orange bars) and wild type (black bars) plants grew vertically on half-strength MS agar plates in the absence (control) or presence of 10 μM ABA or 50 mM NaCl. Data represent mean ± SEM (n = 30). (E) Absence of a salt-dependent growth phenotype in cngc19-1 and cngc20-1. Photographs show representative plants from wild type, cngc19-1, and cngc20-1 after a 12-day growth period in the absence or presence of 75 mM NaCl. (F) Fresh weight of wild type (black circles), cngc19-1 (orange circles), and cngc20-1 (green circles) shoots after a 12-day growth period in the presence of 0, 25, 50, or 75 mM NaCl. Data represent mean ± SEM (n = 6). The dry weight did also not differ significantly between wild type and mutants (not shown). (G) K/Na content in shoots of plants shown in (E) and (F) as a function of the applied salt-concentration. Data represent mean ± SEM (n = 6). Color code as in (F).