@article {20402, title = {Plastome evolution in the sole hemiparasitic genus laurel dodder (Cassytha) and insights into the plastid phylogenomics of Lauraceae}, year = {2017}, abstract = {

To date, little is known about the evolution of plastid genomes (plastomes) in Lauraceae. As one of the top five largest families in tropical forests, the Lauraceae contain many species that are important ecologically and economically. Lauraceous species also provide wonderfulmaterials to study the evolutionary trajectory in response to parasitism because they contain both nonparasitic and parasitic species. This study compared the plastomes of nine Lauraceous species, including the sole hemiparasitic and herbaceous genus Cassytha (laurel dodder; here represented by Cassytha filiformis).We found differential contractions of the canonical inverted repeat (IR), resulting in two IR types present in Lauraceae. These two IR types reinforce Cryptocaryeae and Neocinnamomum\–Perseeae\–Laureae as two separate clades. Our data reveal several traits unique to Cas. filiformis, including loss of IRs, loss or pseudogenization of 11 ndh and rpl23 genes, richness of repeats, and accelerated rates of nucleotide substitutions in protein-coding genes. Although Cas. filiformis is low in chlorophyll content, our analysis based on dN/dS ratios suggests that both its plastid house-keeping and photosynthetic genes are under strong selective constraints. Hence, we propose that short generation time and herbaceous lifestyle rather than reduced photosynthetic ability drive the accelerated rates of nucleotide substitutions in Cas. filiformis.

}, keywords = {genome rearrangement, hemiparasitic plant, Lauraceae, laurel, plastid genome, substitution rate}, doi = {10.1093/gbe/evx177}, author = {Wu, Chung-Shien and Wang, Ting-Jen and Wu, Chia-Wen and Wang, Ya-Nan and Chaw, Shu-Miaw} } @article {20385, title = {Stout camphor tree genome fills gaps in understanding of flowering plant genome evolution}, year = {2019}, abstract = {

We present reference-quality genome assembly and annotation for the stout camphor tree (Cinnamomum kanehirae (Laurales, Lauraceae)), the first sequenced member of the Magnoliidae comprising four orders (Laurales, Magnoliales, Canellales and Piperales) and over 9,000 species. Phylogenomic analysis of 13 representative seed plant genomes indicates that magnoliid and eudicot lineages share more recent common ancestry than monocots. Two whole-genome duplication events were inferred within the magnoliid lineage: one before divergence of Laurales and Magnoliales and the other within the Lauraceae. Small-scale segmental duplications and tandem duplications also contributed to innovation in the evolutionary history of Cinnamomum. For example, expansion of the terpenoid synthase gene subfamilies within the Laurales spawned the diversity of Cinnamomum monoterpenes and sesquiterpenes.

}, author = {Chaw, Shu-Miaw and Liu, Yu-Ching and Wu, Yu-Wei and Wang, Han-Yu and Lin, Chan-Yi I and Wu, Chung-Shien and Ke, Huei-Mien and Chang, Lo-Yu and Hsu, Chih-Yao and Yang, Hui-Ting and Sudianto, Edi and Hsu, Min-Hung and Wu, Kun-Pin and Wang, Ling-Ni and Leebens-Mack, James H and Tsai, Isheng J} }