摘要
Orobanchaceae is the largest family of parasiticplants,containing autotrophic and parasiticplants with all degrees of parasitism.This makes it byfar the best family for studying the origin and evolution of plant parasitism.Here we provide three high-quality genomes of orobanchaceous plants,the autotrophic Lindenbergia luchunensis and the holoparasitic plants Phelipanche aegyptiaca and Orobanche cumana.Phylogenomic analysis of these three genomes together with those previously published and the transcriptomes of other orobanchaceous species createda robust phylogeneticframework forOrobanchaceae.We found that an ancient whole-genome duplication(WGD;about 73.48million years ago),which occurred earlierthan theoriginof Orobanchaceae,mighthave contributed totheemergence of parasitism.However,no WGD events occurred in any lineage of orobanchaceous parasites except for Striga after divergence from their autotrophic common ancestor,suggesting that,in contrast with previous speculations,WGD is not associated with the emergence of holoparasitism.We detected evident convergent gene loss in all parasites within Orobanchaceae and between Orobanchaceae and dodder Cuscuta australis.The gene families in the orobanchaceous parasites showed a clear pattern of recent gains and expansions.The expanded gene families are enriched in functions related to the development of the haustorium,suggesting that recent gene family expansions may have facilitated the adaptation of orobanchaceous parasites to different hosts.This study illustrates a stepwise pattern in the evolution of parasitism in the orobanchaceous parasites and will facilitate future studieson parasitism and the control of parasitic plants in agriculture.
基金
This work was supported by the National Natural Science Foundation of China(32000179 Y.X.)
the Strategic Priority Research Program of Chinese Academy of Sciences(XDPB16 J.W.)
the CAS"Light of West China"Program(G.S.)
the Special Research Assistant of Chinese Academy of Sciences(Y.X.and J.Z.)
the Postdoctoral Directional Training Foundation of Yunnan Province(Y.X.).
