Abstract Detail

Phylogenomics and evolution of Superrosids

Guo, Jing [1], Xu, Weibin [2], Hu, Yi [3], Huang, Jie [1], Zhao, Yiyong [1], Zhang, Lin [1], Huang, Chien-Hsun [1], Ma, Hong  [4].

Phylotranscriptomics in Cucurbitaceae Reveal Multiple Whole Genome Duplications and Key Morphological and Molecular Innovations.

Climbing plants are abundant in tropical rainforests, representing a large number of the floristic diversity and have evolved multiple climbing strategies including tendril, twining stem, hooks, and sticky adventitious roots to acquire sufficient space and sunlight. The climbing habit has arisen independently many times with a great deal phylogenetic diversity covering nearly 65% angiosperm families, and has been hypothesized to be a key innovation of angiosperms. Cucurbiaceae, a family containing ~1000 species and many important crops, is characterized by tendril-based climbing habit and the pepo fruit. Here, we sampled a total of 136 cucurbit species with transcriptomes and genomes, involving 127 newly sequenced ones, representing nearly 90% of all known cucurbit diversity and took multiple nuclear datasets to reconstruct Cucurbitaceae phylogeny. Our results established a robust phylogeny and classified them into eight major clades. We analyzed diversification dynamics, whole genome duplication (WGD), and ancestral morphologies, and found that after early genome duplication event(s), a burst of diversification and morphological innovations in flower, fruit and root characters (tendril, fruit type, pollen size, stamen number, and style number) occurred under the climate optimum in the Early Eocene (58.9-53.2 Ma). Two species-rich clades (Clade VII and VIII), which together comprise ~80% of extant cucurbits species, experienced a rapid increase in diversification near the Mid-Eocene Climatic Optimum (~45 Ma), suggesting a key role in shaping the diversity of cucurbits. We found that the cucurbit-specific tendril identity gene TEN originated from a paleo-polyploidization at the origin of the family. Our results support the hypothesis that cucurbits diversity might be driven by increased genetic materials from polyploidization and new states of traits under drastic changes in paleoclimate.

1 - Fudan University, Institute of Plant Biology, Center of Evolutionary Biology, School of Life Sciences, Shanghai 200433, China
2 - Guangxi Zhuangzu Autonomous Region and Chinese Academy of Sciences, Guangxi Institute of Botany, Guilin 541006, China
3 - Pennsylvania State University, Department of Biology, the Huck Institutes of Life Sciences,, University Park, PA, USA
4 - Dept Biology, 510 Mueller Lab-Penn State Univ, University Park, PA, 16802, United States

Whole-genome duplication

Presentation Type: Colloquium Presentations
Session: COL07, Phylogenomics and evolution of superrosids
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 4:15 PM
Number: COL07005
Abstract ID:348
Candidate for Awards:None

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