Figure 1.

Identification of CAX1 as a candidate gene for the QTL CdTol2. A, Densification of the QTL CdTol2. Five additional markers (red) were used to confirm the localization and reduce the CdTol2 locus to a 3-centiMorgan region [for marker descriptions, see Supplemental Table S3; all other markers are defined in Courbot et al. (2007)]. The vertical dashed line represents the LOD score threshold (1.5) for QTL detection at an error level of α = 0.05. Bars indicate the one-LOD (10-fold) support interval, and whiskers (lines extending beyond bars) indicate the two-LOD (100-fold) support intervals. BC1 individuals were phenotyped at 0.5 mm CaNO₃ in the study by Courbot et al. (2007). B, CAX1 transcript levels in BC1 individuals displaying the Ah/Alp (h) or Alp/Alp (a) allelic combinations at the CdTol2 locus. At least three cuttings for each BC1 genotype were transferred in hydroponic solution according to the work by Courbot et al. (2007) for 4 weeks. Clones were pooled together, and CAX1 expression levels were assessed through qPCR analysis. Data are means ± sd (n = 9). *, P < 0.05 (Student’s t test).