Plastome of mycoheterotrophic Burmannia itoana Mak. (Burmanniaceae) exhibits extensive degradation and distinct rearrangements

PeerJ

article

Xiaojuan Li¹  Xin Qian¹  Gang Yao³  Zhongtao Zhao¹  Dianxiang Zhang¹ 

[1] Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences;College of Life Sciences, University of Chinese Academy of Sciences;South China Limestone Plants Research Center, College of Forestry and Landscape Architecture, South China Agricultural University

关键词: Plastome;    Heterotroph;    Rearrangement;    Burmannia itoana;    Degradation;   

DOI  :  10.7717/peerj.7787

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Plastomes of heterotrophs went through varying degrees of degradation along with the transition from autotrophic to heterotrophic lifestyle. Here, we identified the plastome of mycoheterotrophic species Burmannia itoana and compared it with those of its reported relatives including three autotrophs and one heterotroph (Thismia tentaculata) in Dioscoreales. B. itoana yields a rampantly degraded plastome reduced in size and gene numbers at the advanced stages of degradation. Its length is 44,463 bp with a quadripartite structure. B. itoana plastome contains 33 tentatively functional genes and six tentative pseudogenes, including several unusually retained genes. These unusual retention suggest that the inverted repeats (IRs) regions and possibility of being compensated may prolong retention of genes in plastome at the advanced stage of degradation. Otherwise, six rearrangements including four inversions (Inv1/Inv2/Inv3/Inv4) and two translocations (Trans1/Trans2) were detected in B. itoana plastome vs. its autotrophic relative B. disticha. We speculate that Inv1 may be mediated by recombination of distinct tRNA genes, while Inv2 is likely consequence of extreme gene losses due to the shift to heterotrophic lifestyle. The other four rearrangements involved in IRs and small single copy region may attribute to multiple waves of IRs and overlapping inversions. Our study fills the gap of knowledge about plastomes of heterotroph in Burmannia and provides a new evidence for the convergent degradation patterns of plastomes en route to heterotrophic lifestyle.

【 授权许可】

CC BY