Evolutionary relationships, hybridization and diversification under domestication of the locoto chile (Capsicum pubescens) and its wild relatives

PALOMBO, NAHUEL E.; WEISS-SCHNEEWEISS, HANNA; CARRIZO GARCÍA, CAROLINA

Frontiers in Plant Science

Frontiers Media SA

Año: 2024 vol. 15

Patterns of geneticvariation in crops are the result of multiple processes that haveoccurred during their domestication and improvement, and areinfluenced by their wild progenitors that often remain understudied.The locoto chile, Capsicum pubescens, is a crop grown mainly inmid-highlands of SouthCentral America. This species is not known fromthe wild and exists only as a cultigen. The evolutionary affinitiesand exact origin of C. pubescens have still not been elucidated, withhypotheses suggesting its genetic relatedness and origin to two wildputative ancestral Capsicum species from the Central Andes, C.eximium and C. cardenasii. In the current study, RAD-sequencing wasapplied to obtain genome-wide data for 48 individuals of C. pubescensand its wild allies representing different geographical areas.Bayesian, Maximum Likelihood and coalescent-based analyticalapproaches were used to reconstruct population genetic patterns andphylogenetic relationships of the studied species. The resultsrevealed that C. pubescens forms a well-defined monotypic lineageclosely related to wild C. cardenasii and C. eximium, and also to C.eshbaughii. The primary lineages associated with the diversificationunder domestication of C. pubescens were also identified. Althoughdirect ancestordescendant relationship could not be inferred withinthis group of taxa, hybridization events were detected between C.pubescens and both C. cardenasii and C. eximium. Therefore, althoughhybrid origin of C. pubescens could not be inferred, gene flowinvolving its wild siblings was shown to be an important factorcontributing to its contemporary genetic diversity. The data allowedfor the inference of the center of origin of C. pubescens incentral-western Bolivia highlands and for better understanding of thedynamics of its gene pool. The results of this study are essentialfor germplasm conservation and breeding purposes, and provideexcellent basis for further research of the locoto chile and its wildrelatives.p { margin-bottom: 0.25cm; line-height: 115% }