Phylogenetic relationships and evolution of Physaloids (Physalideae, Solanaceae)

SMITH STACEY D.; DEANNA ROCÍO; BARBOZA GLORIA E.

Quito

Congreso; XII Congreso Latinoamericano de Botánica; 2018

Asociacion Latinoamericana de Botánica

Physalideae is one of the most morphological diverse and genera-rich tribes in the tomato family (Solanaceae). This group is commonly called ?physaloids? for the conspicuous inflated fruiting calyces in many of the genera, including the species-rich Physalis and Deprea. Despite the economic importance of this clade, which includes tomatillo and groundcherries, the evolutionary history and taxonomy of Physalideae are largely unresolved. This work combines molecular phylogenetics with comparative morphological studies to resolve position and circumscription of Physalideae genera and to trace the evolution of the inflated calyx. In order to resolve phylogenetic relationships, we sampled 231 Physalideae species (77 % of the tribe), sequenced four markers (ITS, LEAFY, trnL-F and waxy), and performed a suite of maximum likelihood and Bayesian analyses. Fruiting calyx variation was scored as non-accrescent, partially accrescent-appressed, or inflated, and shifts in character state were estimated with stochastic mapping. Eight out of 30 genera (Alkekengi, Aureliana, Deprea, Leucophysalis, Nothocestrum, Physaliastrum, Quincula, and Vassobia) were resolved as strongly supported monophyletic groups, whereas taxonomical rearrangements are required for the non-monophyletic genera. For example, Brachistus should be synonymized under Witheringia, Chamaesaracha rzedowskiana should be excluded from Chamaesaracha and Tzeltalia calidaria from Tzeltalia. More dramatic disagreements between this phylogeny and current classification are found in Physalis and the Iochrominae subtribe, leading to the need for additional rearrangements. Across the clade, analyses of evolution of calyx accrescence estimated over 80 changes, with shifts between partially accrescent-appressed to inflated calyces roughly twice as common as non-accrescent to partially accrescent-appressed calyces. Overall, calyx inflation is a highly convergent trait, making characters related to flowers and habit more useful for differentiating clades corresponding to genera. This study represents the most extensive phylogenetic reconstruction in the Physalideae tribe to date and provides a robust framework for addressing questions about biogeography and diversification of this species-rich group.