DEPARTMENT OF PLANT SCIENCE AND LANDSCAPE ARCHITECTURE
Spring 2019 Seminar Series
Friday April 12TH at noon, W.B. Young 002
Title: Evolution of Rosaceae fruit types on the basis of a new nuclear-gene phylogeny and impact of whole-genome duplication on fleshy fruits
Speaker: By Hong Ma
Abstract:
Fruits are the defining feature of angiosperms, likely have
contributed to angiosperm successes by protecting and dispersing
seeds, and provide foods to humans and other animals, with many
morphological types and important ecological and agricultural
implications. Rosaceae is a family with ∼3000 species and an
extraordinary spectrum of distinct fruits, including fleshy peach,
apple, and strawberry prized by their consumers, as well as dry
achenetum and follicetum with features facilitating seed dispersal,
excellent for studying fruit evolution. To address Rosaceae fruit
evolution and other questions, we generated 125 new transcriptomic
and genomic datasets and identified hundreds of nuclear genes to
reconstruct a well-resolved Rosaceae phylogeny with highly
supported monophyly of all subfamilies and tribes. Molecular clock
analysis revealed an estimated age of ∼101.6 Ma for crown
Rosaceae and divergence times of tribes and genera, providing a
geological and climate context for fruit evolution. Phylogenomic
analysis yielded strong evidence for numerous whole genome
duplications (WGDs), supporting the hypothesis that the apple tribe
had a WGD and revealing another one shared by fleshy fruitbearing
members of this tribe, with moderate support for WGDs in
the peach tribe and other groups. Ancestral character reconstruction
for fruit types supports independent origins of fleshy fruits from dryfruit
ancestors, including the evolution of drupes (e.g., peach) and
pomes (e.g., apple) from follicetum, and drupetum (raspberry and
blackberry) from achenetum. We propose that WGDs and
environmental factors, including animals, contributed to the evolution
of the many fruits in Rosaceae, which provide a foundation for
understanding fruit evolution.
For more information, contact: PSLA at christine.strand@uconn.edu