Phylogenetic incongruence and interspecific crossability in the tomatillos (Physalis, Solanaceae)

SMITH STACEY D.; DEANNA ROCÍO; PRETZ CHELSEA

Rorchester

Congreso; Botany 2018; 2018

Botanical Society of America

Resolving the phylogeny of the tomatillo genus Physalis has long been challenging due to extensive phylogenetic incongruence. Unlike other genera in the physaloid clade of Solanaceae (the tomato family), analyses of many nuclear and plastid markers have failed to recover consistently supported clades in this group of roughly 90 Neotropical species. Incongruence in a phylogeny can be due to several processes which include, but are not limited to, interspecific gene flow leading to introgression or rapid diversification resulting in incomplete lineage sorting. Distinguishing among these processes can be challenging and requires combining information about geographic distributions, patterns of genetic variation, and reproductive barriers. In the present study, we have conducted interspecific and intraspecific crosses among Physalis species to assess their breeding systems and determine if geographically proximate species are capable of exchanging genes. We focused on four native North American species with varying degrees of range overlap (P. acutifolia, P. cinerascens, P. hederifolia, and P. heterophylla) and included one geographically distant species, P. peruviana from South America. We used these data to test the prediction that overlapping species are cross-fertile, a result which could help to explain the widespread phylogenetic incongruence across the genus. These studies will provide the foundation for future research to directly test the relationship between interspecific hybridization and patterns of genomic variation in this charismatic clade.