Figure 5.

Map-based cloning of CHS2. A, A genetic map of the CHS2 locus on chromosome IV. Positions of the markers used for mapping are indicated above the line. The corresponding nucleotide positions are numbered in kilobases below the line. The number of recombinants is indicated in parentheses. Predicted genes are shown by arrows indicating the direction of transcription. B, A schematic diagram of the genomic structure of the CHS2 gene. Boxes and lines indicate exons and introns, respectively. The nucleotide substitutions in chs2 and chs2-s1 are shown. C, Complementation of the chs2 mutant. Wild-type Col, chs2, and Col transformed with a genomic clone containing the mutated chs2 (Col/CHS2:chs2) were grown at 22°C for 2 weeks (left) and then treated at 4°C for 10 d (right). D, Screening of the chs2 suppressor chs2-s1. EMS-mutagenized chs2 plants were grown at 22°C for 2 weeks and then treated at 4°C for 10 d. E, PR1 gene expression in Col, chs2, Col/CHS2:chs2, and chs2-s1 plants treated at 4°C for 6 d by real-time RT-PCR. The data represent means of three replicates ± sd. Similar results were observed in three independent experiments. F, Trypan blue staining of the leaves from chs2, Col/CHS2:chs2, and chs2-s1 plants. Bar = 100 μm.