Contrasting modes for loss of pungency between cultivated and wild species of Capsicum.

摘要

Studies documenting the inheritance of pungency or 'heat' in pepper (Capsicum spp.) have revealed that mutations at a single locus, Pun1, are responsible for loss of pungency in cultivars of the two closely related species Capsicum annuum and Capsicum chinense. In this study, we present the identification of an unreported null allele of Pun1 from a non-pungent accession of Capsicum frutescens, the third species in the annuum-chinense-frutescens complex of domesticated Capsicums. The loss of pungency phenotype in C. frutescens maps to Pun1 and co-segregates with a molecular marker developed to detect this allele of Pun1, pun1(3). Loss of transcription of pun1(3) is correlated with loss of pungency. Although this mutation is allelic to pun1 and pun1(2), the mutation causing loss of pungency in the undomesticated Capsicum chacoense, pun2, is not allelic to the Pun1 locus as shown by mapping and complementation studies. The different origins of non-pungency in pepper are discussed in the context of the phylogenetic relationship of the known loss of pungency alleles.