Plastome evolution in the Caesalpinia group (Leguminosae) and its application in phylogenomics and populations genetics

Planta ◽  
2021 ◽  
Vol 254 (2) ◽  
Author(s):  
Paulo Aecyo ◽  
André Marques ◽  
Bruno Huettel ◽  
Ana Silva ◽  
Tiago Esposito ◽  
...  
Keyword(s):  
Plastome Evolution

scholarly journals The chloroplast genome evolution of Venus slipper (Paphiopedilum): IR expansion, SSC contraction, and highly rearranged SSC regions

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yan-Yan Guo ◽  
Jia-Xing Yang ◽  
Ming-Zhu Bai ◽  
Guo-Qiang Zhang ◽  
Zhong-Jian Liu
Keyword(s):  
Gene Order ◽  
Inverted Repeat ◽  
Single Copy ◽  
Gene Content ◽  
Comparative Genomic ◽  
Substitution Rates ◽  
Plastome Evolution ◽  
Chloroplast Genomes ◽  
Ideal System ◽  
Small Single Copy

Abstract Background Paphiopedilum is the largest genus of slipper orchids. Previous studies showed that the phylogenetic relationships of this genus are not well resolved, and sparse taxon sampling documented inverted repeat (IR) expansion and small single copy (SSC) contraction of the chloroplast genomes of Paphiopedilum. Results Here, we sequenced, assembled, and annotated 77 plastomes of Paphiopedilum species (size range of 152,130 – 164,092 bp). The phylogeny based on the plastome resolved the relationships of the genus except for the phylogenetic position of two unstable species. We used phylogenetic and comparative genomic approaches to elucidate the plastome evolution of Paphiopedilum. The plastomes of Paphiopedilum have a conserved genome structure and gene content except in the SSC region. The large single copy/inverted repeat (LSC/IR) boundaries are relatively stable, while the boundaries of the inverted repeat and small single copy region (IR/SSC) varied among species. Corresponding to the IR/SSC boundary shifts, the chloroplast genomes of the genus experienced IR expansion and SSC contraction. The IR region incorporated one to six genes of the SSC region. Unexpectedly, great variation in the size, gene order, and gene content of the SSC regions was found, especially in the subg. Parvisepalum. Furthermore, Paphiopedilum provides evidence for the ongoing degradation of the ndh genes in the photoautotrophic plants. The estimated substitution rates of the protein coding genes show accelerated rates of evolution in clpP, psbH, and psbZ. Genes transferred to the IR region due to the boundary shift also have higher substitution rates. Conclusions We found IR expansion and SSC contraction in the chloroplast genomes of Paphiopedilum with dense sampling, and the genus shows variation in the size, gene order, and gene content of the SSC region. This genus provides an ideal system to investigate the dynamics of plastome evolution.

scholarly journals Extensive genomic rearrangements mediated by repetitive sequences in plastomes of Medicago and its relatives

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shuang Wu ◽  
Jinyuan Chen ◽  
Ying Li ◽  
Ai Liu ◽  
Ao Li ◽  
...  
Keyword(s):  
Tandem Repeats ◽  
Genome Instability ◽  
Repetitive Sequences ◽  
Genomic Analysis ◽  
Genomic Rearrangements ◽  
Comparative Genomic ◽  
Length Variation ◽  
Substitution Rates ◽  
Repeat Content ◽  
Plastome Evolution

Abstract Background Although plastomes are highly conserved with respect to gene content and order in most photosynthetic angiosperms, extensive genomic rearrangements have been reported in Fabaceae, particularly within the inverted repeat lacking clade (IRLC) of Papilionoideae. Two hypotheses, i.e., the absence of the IR and the increased repeat content, have been proposed to affect the stability of plastomes. However, this is still unclear for the IRLC species. Here, we aimed to investigate the relationships between repeat content and the degree of genomic rearrangements in plastomes of Medicago and its relatives Trigonella and Melilotus, which are nested firmly within the IRLC. Results We detected abundant repetitive elements and extensive genomic rearrangements in the 75 newly assembled plastomes of 20 species, including gene loss, intron loss and gain, pseudogenization, tRNA duplication, inversion, and a second independent IR gain (IR ~ 15 kb in Melilotus dentata) in addition to the previous first reported cases in Medicago minima. We also conducted comparative genomic analysis to evaluate plastome evolution. Our results indicated that the overall repeat content is positively correlated with the degree of genomic rearrangements. Some of the genomic rearrangements were found to be directly linked with repetitive sequences. Tandem repeated sequences have been detected in the three genes with accelerated substitution rates (i.e., accD, clpP, and ycf1) and their length variation could be explained by the insertions of tandem repeats. The repeat contents of the three localized hypermutation regions around these three genes with accelerated substitution rates are also significantly higher than that of the remaining plastome sequences. Conclusions Our results suggest that IR reemergence in the IRLC species does not ensure their plastome stability. Instead, repeat-mediated illegitimate recombination is the major mechanism leading to genome instability, a pattern in agreement with recent findings in other angiosperm lineages. The plastome data generated herein provide valuable genomic resources for further investigating the plastome evolution in legumes.

scholarly journals Phylogenetic and Comparative Analyses of Complete Chloroplast Genomes of Chinese Viburnum and Sambucus (Adoxaceae)

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1143 ◽  
Author(s):  
Hang Ran ◽  
Yanyan Liu ◽  
Cui Wu ◽  
Yanan Cao
Keyword(s):  
Genomic Structure ◽  
Phylogenetic Analyses ◽  
Sister Relationship ◽  
Plastome Evolution ◽  
Chloroplast Genomes ◽  
Flora Of China ◽  
Phylogenetic Resolution ◽  
Sister Relationships ◽  
Phylogenomic Analyses ◽  
Cp Genome

Phylogenetic analyses of complete chloroplast genome sequences have yielded significant improvements in our understanding of relationships in the woody flowering genus Viburnum (Adoxaceae, Dipsacales); however, these relationships were evaluated focusing only on Viburnum species within Central and South America and Southeast Asia. By contrast, despite being a hotspot of Viburnum diversity, phylogenetic relationships of Viburnum species in China are less well known. Here, we characterized the complete chloroplast (cp) genomes of 21 Viburnum species endemic to China, as well as three Sambucus species. These 24 plastomes were highly conserved in genomic structure, gene order and content, also when compared with other Adoxaceae. The identified repeat sequences, simple sequence repeats (SSRs) and highly variable plastid regions will provide potentially valuable genetic resources for further population genetics and phylogeographic studies on Viburnum and Sambucus. Consistent with previous combined phylogenetic analyses of 113 Viburnum species, our phylogenomic analyses based on the complete cp genome sequence dataset confirmed the sister relationship between Viburnum and the Sambucus-Adoxa-Tetradoxa-Sinadoxa group, the monophyly of four recognized sections in Flora of China (i.e., Viburnum sect. Tinus, Viburnum sect. Solenotinus, Viburnum sect. Viburnum and Viburnum sect. Pseudotinus) and the nonmonophyly of Viburnum sect. Odontotinus and Viburnum sect. Megalotinus. Additionally, our study confirmed the sister relationships between the clade Valvatotinus and Viburnum sect. Pseudotinus, as well as between Viburnum sect. Opulus and the Odontotinus-Megalotinus group. Overall, our results clearly document the power of the complete cp genomes in improving phylogenetic resolution, and will contribute to a better understanding of plastome evolution in Chinese Adoxaceae.

scholarly journals Plastome Reduction in the Only Parasitic Gymnosperm Parasitaxus Is Due to Losses of Photosynthesis but Not Housekeeping Genes and Apparently Involves the Secondary Gain of a Large Inverted Repeat

2019 ◽  
Vol 11 (10) ◽  
pp. 2789-2796 ◽  
Author(s):  
Xiao-Jian Qu ◽  
Shou-Jin Fan ◽  
Susann Wicke ◽  
Ting-Shuang Yi
Keyword(s):  
Inverted Repeat ◽  
Chlorophyll Biosynthesis ◽  
Housekeeping Genes ◽  
Parasitic Plants ◽  
Structural Features ◽  
Regulation System ◽  
Biosynthesis Pathway ◽  
Plastid Genomes ◽  
Plastome Evolution ◽  
Selection For

Abstract Plastid genomes (plastomes) of parasitic plants undergo dramatic reductions as the need for photosynthesis relaxes. Here, we report the plastome of the only known heterotrophic gymnosperm Parasitaxus usta (Podocarpaceae). With 68 unique genes, of which 33 encode proteins, 31 tRNAs, and four rRNAs in a plastome of 85.3-kb length, Parasitaxus has both the smallest and the functionally least capable plastid genome of gymnosperms. Although the heterotroph retains chlorophyll, all genes for photosynthesis are physically or functionally lost, making photosynthetic energy gain impossible. The pseudogenization of the three plastome-encoded light-independent chlorophyll biosynthesis genes chlB, chlL, and chlN implies that Parasitaxus relies on either only the light-dependent chlorophyll biosynthesis pathway or another regulation system. Nesting within a group of gymnosperms known for the absence of the large inverted repeat regions (IRs), another unusual feature of the Parasitaxus plastome is the existence of a 9,256-bp long IR. Its short length and a gene composition that completely differs from those of IR-containing gymnosperms together suggest a regain of this critical, plastome structure-stabilizing feature. In sum, our findings highlight the particular path of lifestyle-associated reductive plastome evolution, where structural features might provide additional cues of a continued selection for plastome maintenance.

scholarly journals Mobile Elements Shape Plastome Evolution in Ferns

2018 ◽  
Vol 10 (10) ◽  
pp. 2558-2571 ◽  
Author(s):  
Tanner A Robison ◽  
Amanda L Grusz ◽  
Paul G Wolf ◽  
Jeffrey P Mower ◽  
Blake D Fauskee ◽  
...  
Keyword(s):  
Mobile Elements ◽  
Plastome Evolution

scholarly journals Punctuated plastome reduction and host–parasite horizontal gene transfer in the holoparasitic plant genus Aphyllon

2018 ◽  
Vol 285 (1887) ◽  
pp. 20181535 ◽  
Author(s):  
Adam C. Schneider ◽  
Harold Chun ◽  
Saša Stefanović ◽  
Bruce G. Baldwin
Keyword(s):  
Mitochondrial Genome ◽  
Gene Tree ◽  
Recent Common Ancestor ◽  
Evolutionary Time ◽  
Fine Grained ◽  
Plastome Evolution ◽  
Chloroplast Genomes ◽  
Stem Lineage ◽  
Patterns And Processes ◽  
Host Parasite

Foundational studies of chloroplast genome (plastome) evolution in parasitic plants have focused on broad trends across large clades, particularly among the Orobanchaceae, a species-rich and ecologically diverse family of root parasites. However, the extent to which such patterns and processes of plastome evolution, such as stepwise gene loss following the complete loss of photosynthesis (shift to holoparasitism), are detectable at shallow evolutionary time scale is largely unknown. We used genome skimming to assemble eight chloroplast genomes representing complete taxonomic sampling of Aphyllon sect. Aphyllon, a small clade within the Orobanchaceae that evolved approximately 6 Ma, long after the origin of holoparasitism. We show substantial plastome reduction occurred in the stem lineage, but subsequent change in plastome size, gene content, and structure has been relatively minimal, albeit detectable. This lends additional fine-grained support to existing models of stepwise plastome reduction in holoparasitic plants. Additionally, we report phylogenetic evidence based on an rbcL gene tree and assembled 60+ kb fragments of the Aphyllon epigalium mitochondrial genome indicating host-to-parasite horizontal gene transfers (hpHGT) of several genes originating from the plastome of an ancient Galium host into the mitochondrial genome of a recent common ancestor of A. epigalium . Ecologically, this evidence of hpHGT suggests that the host–parasite associations between Galium and A. epigalium have been stable at least since its subspecies diverged hundreds of thousands of years ago.

scholarly journals The first complete chloroplast genome of the Genistoid legume Lupinus luteus: evidence for a novel major lineage-specific rearrangement and new insights regarding plastome evolution in the legume family

2014 ◽  
Vol 113 (7) ◽  
pp. 1197-1210 ◽  
Author(s):  
Guillaume E. Martin ◽  
Mathieu Rousseau-Gueutin ◽  
Solenn Cordonnier ◽  
Oscar Lima ◽  
Sophie Michon-Coudouel ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Lupinus Luteus ◽  
Complete Chloroplast Genome ◽  
Major Lineage ◽  
Plastome Evolution

scholarly journals The complete chloroplast genome of Myriophyllum spicatum reveals a 4‐kb inversion and new insights regarding plastome evolution in Haloragaceae

2020 ◽  
Vol 10 (6) ◽  
pp. 3090-3102 ◽  
Author(s):  
Yi‐Ying Liao ◽  
Yu Liu ◽  
Xing Liu ◽  
Tian‐Feng Lü ◽  
Ruth Wambui Mbichi ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Myriophyllum Spicatum ◽  
Complete Chloroplast Genome ◽  
Plastome Evolution

Plastome and Nuclear Phylogenies of Dwarf Mistletoes (Arceuthobium: Viscaceae)

2021 ◽  
Vol 46 (2) ◽  
pp. 389-402
Author(s):  
Adam C. Schneider ◽  
Kate M. Sanders ◽  
Jacob H. Idec ◽  
Yun Jee Lee ◽  
Shawn C. Kenaley ◽  
...  
Keyword(s):  
New World ◽  
Sequence Data ◽  
Strong Support ◽  
Species Level ◽  
Species Relationships ◽  
Plastome Evolution ◽  
Subspecies Level ◽  
Infraspecific Taxa ◽  
Ribosomal Cistron ◽  
Number Of Individuals

Abstract— Dwarf mistletoes are a lineage of morphologically-reduced stem parasites inhabiting Pinaceae and Cupressaceae throughout the northern hemisphere and equatorial East Africa. Though diagnosable by a suite of morphological traits, phylogenetic knowledge of species relationships has been limited to studies employing either comprehensive taxonomic sampling of one or two genes, or more sequence data from a limited number of individuals. We used data from genome skimming to assemble 3kb of the nuclear ribosomal cistron and up to 45kb of the plastome to clarify the phylogenetic root of the genus, monophyly of species, and relationships among infraspecific taxa. Genomic differentiation among terminal taxa was variable; however, we found strong support for reciprocally monophyletic New World and Old World lineages, congruent nrDNA and plastome topologies at the species level and below, and monophyly of most taxonomic sections and species. Plastome gene content was stable across the genus with minimal pseudogenization or loss, as in other hemiparasites, with the notable exception of cemA. These findings form the basis of our re-evaluation of historical biogeographical hypotheses, species- and subspecies-level taxonomy, and plastome evolution in Arceuthobium. More broadly, this work provides a foundation for future clade-focused comparative and biosystematics studies of Arceuthobium.

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