Format: ORAL

Le Min Choo1, 2, Rowan Schley1

1 Department of Geography, University of Exeter, Exeter, United Kingdom 2 Singapore Botanic Gardens, National Parks Board, Singapore

Introgression and duplication are two of the most dramatic phenomena that a genome may encounter, each with myriad outcomes, ranging from increased evolutionary potential through to a heightened likelihood of extinction. Both processes have greatly influenced the evolution of plant diversity, particularly within the legume family which holds more than 20,000 species. Among the most species-rich legume communities occur in tropical rainforests, which are emblematic for their diversity. Accordingly, here we explore the influence of introgression and genome duplication on legume tree genera found in tropical rainforests, spanning the tropics. Sindora, from the Detarioideae subfamily, comprises 20 species found in palaeotropical rainforests, and has experienced whole genome duplication in its history. As such, phylogenetic reconstruction is challenging within the group due to the high abundance of paralogues. Sindora is known to hybridise extensively, forming syngameons of many interfertile species, and so here we investigate whether introgression has contributed to the present day ability of the genus to form interspecific hybrids using a bespoke phylogenetic pipeline that aims to account for paralogy. The extent of the syngameon and the nature of hybridisation are also studied using present day hybrids. Inga, from the Caesalpinioideae subfamily, comprises 300 species and typifies the rapid rainforest tree radiations that gave rise to most Neotropical tree diversity. Introgression can catalyse such events of rapid diversification, and so here we assess whether hybridisation catalysed rapid diversification in Inga. Firstly, we ascertain the extent of introgression across Inga, following which we test whether introgression of loci underlying chemical defences against herbivory facilitated rapid speciation, given the ecological advantage of novel defences in resisting the relentless insect herbivory experienced by rainforest trees. Overall, we aim to assess whether transfer of adaptive variation through introgression helped generate the unmatched diversity of rainforest trees.