Figure 2.

Molecular Identification of the cau1 Gene.

(A) Map-based cloning of the cau1 locus on chromosome 4.

(B) Structure of the CAU1 gene and the mutation in the cau1 allele. Black boxes represent exons, and black lines represent introns. The Arabidopsis Genome Initiative number for CAU1 is At4g31120.

(C) Complementation assay of drought tolerance in cau1. Wild-type, cau1 mutant, 35S/CAU1-cau1 (cau1 harboring construct 35S/CAU1-pBI121), and skb1-2 plants were subjected to dehydration for 12 d, reirrigation, and recovery for 1 week.

(D) Ion accumulation profile of skb1-2. Seven cationic elements in skb1-2 mutant plants were measured by ICP-MS. Open black circles represent Z values (y axis) of individual wild-type controls, and gray lines highlight ion profiles of skb1-2 individuals. Median Z values of the wild type (n > 30) and skb1-2 mutant (n > 30) were calculated, and the consequent ion profiles were outlined by the blue line and the red line, respectively. *P < 0.05 and **P < 0.01.