Figure 2.

csaat1a Knockout Mutants Are Sensitive to UV-B and MMS.

(A) Gene structure of CSAat1A with T-DNA insertion sites found in the csaat1a mutants. Exons, filled black rectangles; introns, solid lines; untranslated regions, filled blue rectangles.

(B) Expression of CSAat1A in wild-type (Col-0) and csaat1a mutant seedlings, and mutant seedlings overexpressing CSAat1A (OE); RT-PCR products after 30 cycles with gene-specific primers and ACTIN as a loading control. Three replicate experiments were performed. a, Col-0; b, csaat1a-1; c, csaat1a-2; d, 35Spro-CSAat1A-Flag in csaat1a-1 (OE-1); e, 35Spro-CSAat1A-Flag in csaat1a-2 (OE-2).

(C) Twelve-day-old wild-type, csaat1a mutant, and CSAat1A OE seedlings were treated with UV-B (130 μmol m⁻² s⁻¹) for 30 min. After treatment, plants were transferred to a growth chamber for 5 d and then photographed. Bars = 1 cm.

(D) Six-day-old wild-type, csaat1a mutant, and CSAat1A OE seedlings were treated with the indicated concentrations of MMS. Photographs were taken 10 d after treatment. Bar = 1 cm.

(E) The fresh weight of 20 seedlings from each group shown in (C) was measured. All data represent means ± se of at least five replicate experiments (Student’s t test, **P < 0.01).

(F) The fresh weight of 10 seedlings from each group shown in (D) was measured. All data represent means ± se of at least five replicate experiments (Student’s t test, *P < 0.05 and **P<0.01).