The first complete plastid genome of Burmannia disticha L. from the mycoheterotrophic monocot family Burmanniaceae

Abstract

Burmanniaceae is one major group within the monocot order Dioscoreales that has not had its plastome sequenced. Members of Burmanniaceae are mostly achlorophyllous, although the genus Burmannia also includes autotrophs. Here, we report sequencing and analysis of the first Burmanniaceae plastid genome from Burmannia disticha L.. This plastome is 157,480 bp and was assembled as a circular sequence with the typical quadripartite structure of plant plastid genomes. This plastome has a regular number of potentially functional genes with a total of 111, including 78 protein coding genes, 4 ribosomal RNA (rRNA) genes, and 29 tRNA genes. The ratio of the total length of genic:intergenic DNA is 1.58:1, and the mean length of intergenic regions is 398 bp, the longest being 1918 bp. The overall GC content of the B. disticha plastome is 34.90%, and the IR regions in B. disticha are more GC rich (39.50%) than the LSC (32.30%) and SSC (28.80%) regions. Phylogenetic analysis of protein-coding sequences from plastomes of related species in the order Dioscoreales support a clade comprising Burmanniaceae and Dioscoreaceae. This phylogenetic placement is congruent with previous findings based on nuclear and mitochondrial evidence.

The Complete Chloroplast Genome of Trichopus zeylanicus, And Phylogenetic Analysis with Dioscoreales

“…As shown in the previous studies, our comparison also confirmed that the IR region was more conserved than the LSC and SSC regions within these species ( Fig. 3; Zhao et al, 2018;Ma et al, 2018).…”

“…The intron and intergenic spacer region covered 36.1% of the genome (intron 7%, and intergenic spacer 29%). Overall guanine-cytosine (GC) content of T. zeylanicus chloroplast genome was 37.24% which is similar to closely related species (Zhao et al, 2018;Ma et al, 2018). The GC contents of the LSC and SSC regions are 31.5% and 31.4%, respectively, whereas that of the IR regions is 42.2%.…”

“…5). As previously shown, in all selected Dioscoreaceae species, except in D. zingiberensis, the junction between IRb and LSC (JLB) located within rps19 (IRb expanded to 2 to 279 bp of the 5¢-end of this gene; Ma et al, 2018). Difference in JLB boundary was also observed within Nartheciaceae species.…”

“…The comparison of chloroplast genome of three families of Dioscoreales (Dioscoreaceae, Burmanniaceae, and Nartheciaceae) and their evolutionary relationship was previously reported (Zhao et al, 2018;Ma et al, 2018). In this study, we extended the comparative analysis by including 11 Dioscoreales representing five families (Dioscoreaceae, Nartheciaceae, Taccaceae, Burmanniaceae, and Trichopodaceae; Table 2).…”

Peer Review #3 of "Plastome of mycoheterotrophic Burmannia itoana Mak. (Burmanniaceae) exhibits extensive degradation and distinct rearrangements (v0.1)"

“…Burmannia contains about 60 species spanning from autotrophic, hemi-mycoheterotrophic to mycoheterotrophic (Jonker 1938;Zhang 1999;Wu et al 2010), which could provide an excellent model system for understanding the evolution of plastome responding to the lifestyle shift from autotrophic to heterotrophic. Although the plastome of autotrophic Burmannia disticha (Ma et al 2018) has been described, the plastome of mycoheterotrophic species in Burmannia has never been reported, hindering our efforts in elucidation of plastid evolution in the genus. Aiming to provide new evidence in our understanding of the mechanism of plastid evolution in mycoheterotrophic angiosperms, here we focus on Burmannia itoana, a mycoheterotrophic perennial herb ( Fig.…”