Abstract
Pungency in the fruit of pepper (Capsicum spp.) is due to the accumulation of capsaicinoids. We isolated two genes characterized as putative Capsicum acyl-transferase genes (Catf-1 and Catf-2) from the placenta of pungent pepper, which displayed consensus motifs of acyl-transferase, H***D and DFG*G. The expression pattern of Catf-1 coincided with the accumulation of capsaicinoids in pungent pepper. The Catf-1 was expressed in placenta of pungent pepper fruit, but not in other organs, such as leaf, flower, seed and pericarp. Accumulation of mRNA of Catf-1 varied with the developmental stages of the pungent pepper fruits. Genomic PCR and Southern blot studies revealed the presence of a sequence deletion at the 5′ end of the Catf-1 coding region in the non-pungent line. In the F2 population obtained from a cross between a non-pungent strain (‘mGTY-1’) and a pungent strain (‘277 long’), the genotype at the Catf-1 locus cosegregated with the phenotype for fruit pungency. These results suggest that Catf-1 is a candidate gene differentiating pungent from non-pungent peppers.
