Deeply Altered Genome Architecture in the Endoparasitic Flowering Plant Sapria himalayana Griff. (Rafflesiaceae)

第一作者：Liming Cai

第一单位：哈佛大学

通讯作者：Charles C. Davis

 Abstract 

背景回顾：Despite more than 2,000-fold variation in genome size, key features of genome architecture are largely conserved across angiosperms.

提出问题：Parasitic plants have elucidated the many ways in which genomes can be modified, yet we still lack comprehensive genome data for species that represent the most extreme form of parasitism.

主要研究：Here, we present the highly modified genome of the iconic endophytic parasite Sapria himalayana Griff. (Rafflesiaceae), which lacks a typical plant body.

结果1-基因丢失：First, 44% of the genes conserved in eurosids are lost in Sapria, dwarfing previously reported levels of gene loss in vascular plants. These losses demonstrate remarkable functional convergence with other parasitic plants, suggesting a common genetic roadmap underlying the evolution of plant parasitism.

结果2-内含子变异：Second, we identified extreme disparity in intron size among retained genes. This includes a category of genes with introns longer than any so far observed in angiosperms, nearing 100 kb in some cases, and a second category of genes with exceptionally short or absent introns.

结果3-基因水平转移：Finally, at least 1.2% of the Sapria genome, including both genic and intergenic content, is inferred to be derived from host-to-parasite horizontal gene transfers (HGTs) and includes genes potentially adaptive for parasitism.

结果4-寄生历史：Focused phylogenomic reconstruction of HGTs reveals a hidden history of former host-parasite associations involving close relatives of Sapria’s modern hosts in the grapevine family.结论：Our findings offer a unique perspective into how deeply angiosperm genomes can be altered to fit an extreme form of plant parasitism and demonstrate the value of HGTs as DNA fossils to investigate extinct symbioses.

 通讯作者 

**Charles C. Davis**

doi: https://doi.org/10.1016/j.cub.2020.12.045

Journal: Current Biology

Published date: Jan 22, 2021