Genes Rpl2 Research Articles

Taken to extremes: Loss of plastid rpl32 in Streptophyta and Cuscuta’s unconventional solution for its replacement

The evolution of plant genomes is riddled with exchanges of genetic material within one plant (endosymbiotic gene transfer/EGT) and between unrelated plants (horizontal gene transfer/HGT). These exchanges have left their marks on plant genomes. Parasitic plants with their special evolutionary niche provide ample examples for these processes because they are under a reduced evolutionary pressure to maintain autotrophy and thus to conserve their plastid genomes. On the other hand, the close physical connections with different hosts enabled them to acquire genetic material from other plants. Based on an analysis of an extensive dataset including the parasite Cuscuta campestris and other parasitic plant species, we identified a unique evolutionary history of rpl32 genes coding for an essential plastid ribosomal subunit in Cuscuta. Our analysis suggests that the gene was most likely sequestered by HGT from a member of the Oxalidales order serving as host to an ancestor of the Cuscuta subgenus Grammica. Oxalidales had suffered an ancestral EGT of rpl32 predating the evolution of the genus Cuscuta. The HGT subsequently relieved the plastid rpl32 from its evolutionary constraint and led to its loss from the plastid genome. The HGT-based acquisition in Cuscuta is supported by a high sequence similarity of the mature L32 protein between species of the subgenus Grammica and representatives of the Oxalidales, and by a surprisingly conserved transit peptide, whose functionality in Cuscuta was experimentally verified. The findings are discussed in view of an overall pattern of EGT events for plastid ribosomal subunits in Streptophyta.

Unified Assembly of Chloroplast Genomes: A Comparative Study of Grapes Representing Global Geographic Diversity

The genus Vitis, known for its economically important fruit—grape—is divided into three geographical groups, American, East Asian, and Eurasian, along with a hybrid group. However, previous studies on grape phylogeny using chloroplast genomes have been hindered by limited sample sizes and inconsistent methodologies, resulting in inaccuracies. In this study, we employed the GetOrganelle software with consistent parameters to assemble the chloroplast genomes of 21 grape cultivars, ensuring comprehensive representation across four distinct groups. A comparative analysis of the 21 grape cultivars revealed structural variation, showing chloroplast genome sizes ranging from 160,813 bp to 161,275 bp. In 21 Vitis cultivars, genome annotation revealed 134 to 136 genes, comprising 89 to 91 protein-coding genes (PCGs), 37 tRNAs, and 8 rRNAs. Our observations have pinpointed specific occurrences of contraction and expansion phenomena at the interfaces between inverted repeat (IR) regions and single-copy (SC) regions, particularly in the vicinity of the rpl2, ycf1, ndhF, and trnN genes. Meanwhile, a total of 193 to 198 SSRs were identified in chloroplast genomes. The diversification pattern of chloroplast genomes exhibited strong concordance with the phylogenetic relationships of the Euvitis subgenera. Phylogenetic analysis based on conserved chloroplast genome strongly clustered the grape varieties according to their geographical origins. In conclusion, these findings enhance our understanding of chloroplast genome variation in Vitis populations and have important implications for cultivar selection, breeding, and conservation efforts.

Chloroplast genome sequencing and divergence analysis of 18 Pyrus species: insights into intron length polymorphisms and evolutionary processes.

Pears constitute an essential temperate crop and are primarily produced through interspecific hybridization owing to self-incompatibility that complicates their breeding history. To address this, we sequenced the complete chloroplast (cp) genomes of 18 Pyrus and one Malus species using the Illumina HiSeq4000 platform. The cp genomes ranged from 159,885 bp to 160,153bp and exhibited a conserved circular DNA structure with an average GC content of 36.5%. Each cp genome contained 127 genes, including 83 protein-coding, 36 tRNA, and 8 rRNA genes. Divergence analysis with mVISTA showed high conservation in the coding regions and notable variations in the non-coding regions. All species shared 17 intron-containing genes, with ycf3 and clpP each having two introns. Five intron-containing genes (ndhB, rpl2, rps12, trnA-UGC, and trnE-UUC) were located in the inverted repeat regions, while trnL-UAA was located in the large single-copy region, with conserved intron lengths across Pomoideae. We identified polymorphic intron sequences in the rpl22, petB, clpP, ndhA, and rps16 genes and designed primers for these regions. Notably, the two Pyrus ussuriensis accessions Doonggeullebae and Cheongdangrori showed intron-length polymorphisms despite being classified as the same species. Phylogenetic analysis of the cp genome sequences revealed two major clusters, indicating distinct maternal lineages and evolutionary origins. This study underscores the importance of cp gene polymorphisms in P. fauriei, P. calleryana, P. ussuriensis, and P. pyrifolia, providing valuable insights into Pyrus evolution as well as aiding in the conservation and breeding of pear germplasm.

Study on the role of RPL23 gene in active immunity of termite Reticulitermes chinensis against Metarhizium anisopliae

Ribosomal proteins are considered to be involved in the immunity of different animals against pathogens. The protein level of RPL23 increased after fungal infection in termites, but how it influence active immunity in termites is unknown. The role of RPL23 gene was studied to evaluate its impact on active immunity of termite Reticulitermes chinensis against entomopathogenic fungus (EPF) Metarhizium anisopliae. The RPL23 gene fragment (414 bp) was cloned and phylogenetic analysis revealed that it’s very close to termite Coptotermes formosanus. Expression of RPL23 gene was significantly higher in abdomen as compared to thorax and head. Silencing RPL23 gene had no significant impact on the frequency and time of allogrooming towards fungus exposed termites from nestmates, which showed that nestmates acquired spores from infected termites through allogrooming. Expression of immune genes (GNBP1, GNBP2 and phenoloxidase) and apoptosis related genes (TNF-α, caspase 1, caspase 3 and caspase 8) decreased significantly in nestmates of fungus-treated termites after silencing of RPL23 gene as compared to control. Antifungal activity and survival of RPL23 silenced nestmates of fungus-treated termites also decreased. To sum up, this study found that silencing of RPL23 gene broke the active immunity against M. anisopliae infection, reduced the antifungal activity of termites, weakened cell apoptosis, and led to increased mortality of termites, which may help to find a potential alternative for chemical insecticides to control termites.

The Complete Chloroplast Genome of Meconopsis simplicifolia and Its Genetic Comparison to Other Meconopsis Species.

Background: Chloroplasts, due to their high conservation and lack of recombination, serve as important genetic resources for the classification and evolutionary analysis of closely related species that are difficult to distinguish based on their morphological features. Meconopsis simplicifolia (M. simplicifolia), an endangered herb within the Meconopsis genus, has demonstrated therapeutic potential in treating various diseases. However, the highly polymorphic morphology of this species poses a challenge for accurate identification. Methods: In this study, the complete chloroplast genome of M. simplicifolia was sequenced and assembled using Illumina sequencing technology. Simple sequence repeats (SSRs) and repetitive sequences were characterized. In addition, a comparative analysis was conducted with the chloroplast genomes of six other Meconopsis species. Results: The chloroplast genome of M. simplicifolia has a quadripartite circular structure with a total length of 152,772 bp. It consists of a large single-copy region of 83,824 bp and a small single-copy region of 17,646 bp, separated by a pair of inverted repeat sequences (IRa and IRb, 25,651 bp). The genome contains 131 genes, 33 SSRs, and 27 long repetitive sequences. Comparative analysis with six other chloroplast genomes of Meconopsis revealed that M. simplicifolia is closely related to M. betonicifolia and that the rpl2 (ribosomal protein L2) gene in the IRb region has been deleted. This deletion is of significant importance for future taxonomic studies of M. simplicifolia. Conclusions: This study provides a valuable reference for the identification of M. simplicifolia and contributes to a deeper understanding of the phylogeny and evolution of the Meconopsis genus.

Comparative analyses of plastomes in Allaeanthus and Malaisia: structure, evolution, and phylogeny.

The small genera Allaeanthus and Malaisia within the Moraceae have important edible, medicinal, and economic value. However, complete plastome blueprints and a well-resolved evolutionary history of these two genera are still lack, thereby limiting their conservation and application. The recent discovery of a new distribution of Allaeanthus kurzii in Hainan, China, marked by the collection of two unique samples, alongside three samples of Malaisia scandens, has opened new avenues for research. This study aimed to compare the Allaeanthus and Malaisia plastomes of Hainan Province samples with those of samples from other regions, focusing on plastome structure, codon usage bias, natural selection, and the evolutionary history of A. kurzii and M. scandens. The results showed that both species had a quadripartite plastome structure, with sizes ranging from 162,134 to 162,170bp for A. kurzii and 161,235 to 162,134bp for M. scandens. Both species displayed loss of the infA gene and reduction of the rpl22 gene. Two highly variable regions (petD-trnD-GUC and rpl20-clpP) and three highly variable genes (rpl20, petB, and rpl16) were identified in A. kurzii, while two highly variable regions (ycf2-ndhB and ccsA-ndhE) and three highly variable genes (psbT, rpl36, and ycf2) were found in M. scandens. The protein-coding sequences (CDSs) of the Allaeanthus and Malaisia plastomes exhibited similar patterns of adaptive indices and codon usage frequencies. The genes associated with photosynthesis underwent strong purifying selection. Phylogenetic analysis revealed that Allaeanthus, Broussonetia, and Malaisia constituted a monophyletic group, with Malaisia being more closely related to Broussonetia. Broussonetia diversified approximately 19.78 million years ago, Malaisia approximately 4.74 million years ago, and Allaeanthus approximately 16.18 million years ago. These new plastome-based discoveries will guide conservation planners and medicinal plant breeders and genetic resource development for these species in the region.

Chloroplast genomes of Simarouba Aubl., molecular evolution and comparative analyses within Sapindales

Simarouba, a neotropical genus in the family Simaroubaceae, currently lacks comprehensive genomic data in existing databases. This study aims to fill this gap by providing genomic resources for three Simarouba species, S. amara, S. versicolor, and S. glauca. It also aims to perform comparative molecular evolutionary analyses in relation to other species within the order Sapindales. The analysis of these three Simarouba species revealed the presence of the typical quadripartite structure expected in plastomes. However, some pseudogenization events were identified in the psbC, infA, rpl22, and ycf1 genes. In particular, the CDS of the psbC gene in S. amara was reduced from 1422 bp to 584 bp due to a premature stop codon. Nucleotide diversity data pointed to gene and intergenic regions as promising candidates for species and family discrimination within the group, specifically matK, ycf1, ndhF, rpl32, petA-psbJ, and trnS-trnG. Selection signal analyses showed strong evidence for positive selection on the rpl23 gene. Phylogenetic analyses indicated that S. versicolor and S. glauca have a closer phylogenetic relationship than S. amara. We provide chloroplast genomes of three Simaruba species and use them to elucidate plastome evolution, highlight the presence of pseudogenization, and identify potential DNA barcode regions.

The plastomes of Lepismium cruciforme (Vell.) Miq and Schlumbergera truncata (Haw.) Moran reveal tribe-specific rearrangements and the first loss of the trnT-GGU gene in Cactaceae.

Recent studies have revealed atypical features in the plastomes of the family Cactaceae, the largest lineage of succulent species adapted to arid and semi-arid regions. Most plastomes sequenced to date are from short-globose and cylindrical cacti, while little is known about plastomes of epiphytic cacti. Published cactus plastomes reveal reduction and complete loss of IRs, loss of genes, pseudogenization, and even degeneration of tRNA structures. Aiming to contribute with new insights into the plastid evolution of Cactaceae, particularly within the tribe Rhipsalideae, we de novo assembled and analyzed the plastomes of Lepismium cruciforme and Schlumbergera truncata, two South American epiphytic cacti. Our data reveal many gene losses in both plastomes and the first loss of functionality of the trnT-GGU gene in Cactaceae. The trnT-GGU is a pseudogene in L. cruciforme plastome and appears to be degenerating in the tribe Rhipsalideae. Although the plastome structure is conserved among the species of the tribe Rhipsalideae, with tribe-specific rearrangements, we mapped around 200 simple sequence repeats and identified nine nucleotide polymorphism hotspots, useful to improve the phylogenetic resolutions of the Rhipsalideae. Furthermore, our analysis indicated high gene divergence and rapid evolution of RNA editing sites in plastid protein-coding genes in Cactaceae. Our findings show that some characteristics of the Rhipsalideae tribe are conserved, such as plastome structure with IRs containing only the ycf2 and two tRNA genes, structural degeneration of the trnT-GGU gene and ndh complex, and lastly, pseudogenization of rpl33 and rpl23 genes, both plastid translation-related genes.

Chloroplast genomes of Eriobotrya elliptica and an unknown wild loquat “YN-1”

The chloroplast genomes of wild loquat can help to determine their place in the history of evolution. Here, we sequenced and assembled two novel wild loquat’s chloroplast genomes, one is Eriobotrya elliptica, and the other is an unidentified wild loquat, which we named “YN-1”. Their sizes are 159,471 bp and 159,399 bp, respectively. We also assembled a cultivated loquat named ‘JFZ’, its chloroplast genome size is 159,156 bp. A comparative study was conducted with six distinct species of loquats, including five wild loquats and one cultivated loquat. The results showed that both E. elliptica and “YN-1” have 127 genes, one gene more than E. fragrans, which is psbK. Regions trnF-GAA-ndhJ, petG-trnP-UGG, and rpl32-trnL-UAG were found to exhibit high variability. It was discovered that there was a positive selection on rpl22 and rps12. RNA editing analysis found several chilling stress-specific RNA editing sites, especially in rpl2 gene. Phylogenetic analysis results showed that “YN-1” is closely related to E. elliptica, E. obovata and E. henryi.

Plastome evolution of Engelhardia facilitates phylogeny of Juglandaceae

BackgroundEngelhardia (Juglandaceae) is a genus of significant ecological and economic importance, prevalent in the tropics and subtropics of East Asia. Although previous efforts based on multiple molecular markers providing profound insights into species delimitation and phylogeography of Engelhardia, the maternal genome evolution and phylogeny of Engelhardia in Juglandaceae still need to be comprehensively evaluated. In this study, we sequenced plastomes from 14 samples of eight Engelhardia species and the outgroup Rhoiptelea chiliantha, and incorporated published data from 36 Juglandaceae and six outgroup species to test phylogenetic resolution. Moreover, comparative analyses of the plastomes were conducted to investigate the plastomes evolution of Engelhardia and the whole Juglandaceae family.ResultsThe 13 Engelhardia plastomes were highly similar in genome size, gene content, and order. They exhibited a typical quadripartite structure, with lengths from 161,069 bp to 162,336 bp. Three mutation hotspot regions (TrnK-rps16, ndhF-rpl32, and ycf1) could be used as effective molecular markers for further phylogenetic analyses and species identification. Insertion and deletion (InDels) may be an important driving factor for the evolution of plastomes in Juglandoideae and Engelhardioideae. A total of ten codons were identified as the optimal codons in Juglandaceae. The mutation pressure mostly contributed to shaping codon usage. Seventy-eight protein-coding genes in Juglandaceae experienced relaxed purifying selection, only rpl22 and psaI genes showed positive selection (Ka/Ks > 1). Phylogenetic results fully supported Engelhardia as a monophyletic group including two sects and the division of Juglandaceae into three subfamilies. The Engelhardia originated in the Late Cretaceous and diversified in the Late Eocene, and Juglandaceae originated in the Early Cretaceous and differentiated in Middle Cretaceous. The phylogeny and divergence times didn’t support rapid radiation occurred in the evolution history of Engelhardia.ConclusionOur study fully supported the taxonomic treatment of at the section for Engelhardia species and three subfamilies for Juglandaceae and confirmed the power of phylogenetic resolution using plastome sequences. Moreover, our results also laid the foundation for further studying the course, tempo and mode of plastome evolution of Engelhardia and the whole Juglandaceae family.

Multilocus sequence analysis of ‘Candidatus Phytoplasma asteris’ associated with phyllody of cucumber in India and development of loop‐mediated isothermal amplification (LAMP) assay for its detection

A survey assessed cucumber phyllody disease incidence in Chikkaballapura, Bengaluru Rural, Bengaluru Urban, and Bagalkote districts of Karnataka, India. The average disease incidence ranged from 8 to 18 %. A total of 9 samples showing phyllody and little leaf symptoms were collected and association of phytoplasma was confirmed through 16S rRNA gene amplification, using universal primer pair P1/P7, and followed by nested PCR using primer R16F2n/R16R2. Further, characterization through multilocus sequence analysis targeting secY and rpl22 genes confirmed all nine strains as part of the 16SrI group ('Candidatus Phytoplasma asteris'). Additionally, four weed species (Lecusa aspera, Parthenium hysterophorus, Acaranthus sp., and Amaranthus viridis) found in cucumber fields tested positive for phytoplasma (16SrI) disease. In-silico RFLP analysis of the amplified F2n/R2 region of the 16S rRNA gene indicated that two phytoplasma strains (CuPP1 and CuPP3) from Chikkaballapura belonged to subgroup X (16SrI-X), one phytoplasma strain (CuPP2) belonged to subgroup B (16SrI–B). While the remaining strains from Bangalore Urban, Bengaluru Rural, and Bagalkote districts belonged to subgroup B (16SrI–B). A loop-mediated isothermal amplification (LAMP) detection protocol was also developed for 'Ca P. asteris', targeting the phytoplasma 16S ribosomal DNA. Comparison of assay sensitives demonstrated that LAMP technique is highly efficient and could detect the presence of phytoplasma up to 50 fg of template DNA. LAMP-based detection offers superior ease of use, cost-effectiveness, and rapid results. To the best of our knowledge, this is the first report of phytoplasma causing phyllody disease in cucumber crop in India.

Genetic Variation among the Partial Gene Sequences of the Ribosomal Protein Large-Two, the Internal Transcribed Spacer, and the Small Ribosomal Subunit of Blastocystis sp. from Human Fecal Samples.

In the present study, we compared the genetic variability of fragments from the internal transcribed spacer region (ITS) and the small subunit ribosomal DNA (SSUrDNA) as nuclear markers, in contrast with the ribosomal protein large two (rpl2) loci, placed in the mitochondrion-related organelles (MROs) within and among human fecal samples with Blastocystis. Samples were analyzed using polymerase chain reaction (PCR)-sequencing, phylogenies, and genetics of population structure analyses were performed. In total, 96 sequences were analyzed, i.e., 33 of SSUrDNA, 35 of rpl2, and 28 of ITS. Only three subtypes (STs) were identified, i.e., ST1 (11.4%), ST2 (28.6%), and ST3 (60%); in all cases, kappa indexes were 1, meaning a perfect agreement among ST assignations. The topologies of phylogenetic inferences were similar among them, clustering to each ST in its specific cluster; discrepancies between phylogeny and assignment of STs were not observed. The STRUCTURE v2.3.4 software assigned three subpopulations corresponding to the STs 1-3, respectively. The population indices were consistent with those previously reported by other groups. Our results suggest the potential use of the ITS and rpl2 genes as molecular markers for Blastocystis subtyping as an alternative approach for the study of the genetic diversity observed within and between human isolates of this microorganism.

Complete chloroplast genome of Saxifraga fortunei var. pilosissima (Saxifragaceae) endemic to Ulleung-do island, Korea

The Saxifraga fortunei var. pilosissima Nakai is an endemic species to Ulleung-do island. Here we report the complete chloroplast genome sequence of S. fortunei var. pilosissima, which was 151,186 bp in total length with the large single copy (LSC) region of 83,536 bp, the small single copy (SSC) region of 17,644 bp, and two inverted repeat (IR) regions of 25,003 bp. The chloroplast genome contained 131 genes, including 86 protein-coding, 37 tRNA, 8 rRNA genes, and GC (guanine-cytosine) content was 37.8%. Additionally, we found that the chloroplast genome of S. fortunei var. pilosissima exhibited intron loss in the rpl2 gene. Within the IR region, six protein-coding genes, seven tRNA genes, and four rRNA genes were duplicated. In the chloroplast genome of S. fortunei var. pilosissima, there are a total of 17 genes containing introns. Among them, 15 genes contain one intron each, while two genes contain two introns. Phylogenetic analysis based on 37 representative chloroplast genomes of the Saxifragaceae suggested that genus Saxifraga is monophyletic and S. fortunei var. pilosissima is placed in sect. Irregulares Haw. and grouped with S. fortunei, S. rufescens, and S. stolonifera with a strong maximum likelihood bootstrap support value.

Two chloroplast genomes with reduced inverted repeat regions in Mammillaria series Stylothelae (Cactaceae)

Background: The chloroplast genomes of Cactaceae exhibit boundary modifications in the inverted repeat regions (IRs), gene inversions, and deletions. Among nine Mammillaria species, three distinct chloroplast structures have been identified, although not all of these correspond to the morphology-based classification of the genus.
 Question: Is there a distinct chloroplast genome structure in the species of Mammillaria series Stylothelae?
 Studied species: Mammillaria bocasana and M. erythrosperma.
 Study site and dates: Mexico from 2019 to 2023.
 Methods: Chloroplast DNA was sequenced, and chloroplast genomes were de novo assembled using the Fast-Plast program. Complete plastome sequences were annotated and verified. The sequences were aligned in MAUVE program to detect possible structural changes. A maximum likelihood phylogeny was executed to evaluate the relationships of the studied species.
 Results: The plastomes ranged from 107,368 bp in Mammillaria bocasana to 108,069 bp in M. erythrosperma. Both presented a quadripartite structure and contained 108 genes. The IRs were ~ 1,600 bp long and included the genes rpl2, rpl23 (pseudo), and trnI-CAU. MAUVE identified a ~ 21 kb inversion in the large single copy containing a block of genes related to photosynthesis. The phylogenetic analysis placed both species in a single clade separated from the other species within Mammillaria subg. Mammillaria.
 Conclusions: The studied species of Mammillaria series Stylothelae exhibited a different and synapomorphic chloroplast genome structure. Other Mammillaria chloroplast genome structures have evolved independently in different lineages.

Comparative plastome analysis of the sister genera Ceratocephala and Myosurus (Ranunculaceae) reveals signals of adaptive evolution to arid and aquatic environments

BackgroundExpansion and contraction of inverted repeats can cause considerable variation of plastid genomes (plastomes) in angiosperms. However, little is known about whether structural variations of plastomes are associated with adaptation to or occupancy of new environments. Moreover, adaptive evolution of angiosperm plastid genes remains poorly understood. Here, we sequenced the complete plastomes for four species of xerophytic Ceratocephala and hydrophytic Myosurus, as well as Ficaria verna. By an integration of phylogenomic, comparative genomic, and selection pressure analyses, we investigated evolutionary patterns of plastomes in Ranunculeae and their relationships with adaptation to dry and aquatic habitats.ResultsOwing to the significant contraction of the boundary of IRA/LSC towards the IRA, plastome sizes and IR lengths of Myosurus and Ceratocephala are smaller within Ranunculeae. Compared to other Ranunculeae, the Myosurus plastome lost clpP and rps16, one copy of rpl2 and rpl23, and one intron of rpoC1 and rpl16, and the Ceratocephala plastome added an infA gene and lost one copy of rpl2 and two introns of clpP. A total of 11 plastid genes (14%) showed positive selection, two genes common to Myosurus and Ceratocephala, seven in Ceratocephala only, and two in Myosurus only. Four genes showed strong signals of episodic positive selection. The rps7 gene of Ceratocephala and the rpl32 and ycf4 genes of Myosurus showed an increase in the rate of variation close to 3.3 Ma.ConclusionsThe plastomic structure variations as well as the positive selection of two plastid genes might be related to the colonization of new environments by the common ancestor of Ceratocephala and Myosurus. The seven and two genes under positive selection might be related to the adaptation to dry and aquatic habitats in Ceratocephala and Myosurus, respectively. Moreover, intensified aridity and frequent sea-level fluctuations, as well as global cooling, might have favored an increased rate of change in some genes at about 3.3 Ma, associated with adaptation to dry and aquatic environments, respectively. These findings suggest that changing environments might have influenced structural variations of plastomes and fixed new mutations arising on some plastid genes owing to adaptation to specific habitats.

Extreme Reconfiguration of Plastid Genomes in Papaveraceae: Rearrangements, Gene Loss, Pseudogenization, IR Expansion, and Repeats.

The plastid genomes (plastomes) of angiosperms are typically highly conserved, with extreme reconfiguration being uncommon, although reports of such events have emerged in some lineages. In this study, we conducted a comprehensive comparison of the complete plastomes from twenty-two species, covering seventeen genera from three subfamilies (Fumarioideae, Hypecooideae, and Papaveroideae) of Papaveraceae. Our results revealed a high level of variability in the plastid genome size of Papaveraceae, ranging from 151,864 bp to 219,144 bp in length, which might be triggered by the expansion of the IR region and a large number of repeat sequences. Moreover, we detected numerous large-scale rearrangements, primarily occurring in the plastomes of Fumarioideae and Hypecooideae. Frequent gene loss or pseudogenization were also observed for ndhs, accD, clpP, infA, rpl2, rpl20, rpl32, rps16, and several tRNA genes, particularly in Fumarioideae and Hypecooideae, which might be associated with the structural variation in their plastomes. Furthermore, we found that the plastomes of Fumarioideae exhibited a higher GC content and more repeat sequences than those of Papaveroideae. Our results showed that Papaveroideae generally displayed a relatively conserved plastome, with the exception of Eomecon chionantha, while Fumarioideae and Hypecooideae typically harbored highly reconfigurable plastomes, showing high variability in the genome size, gene content, and gene order. This study provides insights into the plastome evolution of Papaveraceae and may contribute to the development of effective molecular markers.

A connection between the ribosome and two S. pombe tRNA modification mutants subject to rapid tRNA decay.

tRNA modifications are crucial in all organisms to ensure tRNA folding and stability, and accurate translation. In both the yeast Saccharomyces cerevisiae and the evolutionarily distant yeast Schizosaccharomyces pombe, mutants lacking certain tRNA body modifications (outside the anticodon loop) are temperature sensitive due to rapid tRNA decay (RTD) of a subset of hypomodified tRNAs. Here we show that for each of two S. pombe mutants subject to RTD, mutations in ribosomal protein genes suppress the temperature sensitivity without altering tRNA levels. Prior work showed that S. pombe trm8Δ mutants, lacking 7-methylguanosine, were temperature sensitive due to RTD, and that one class of suppressors had mutations in the general amino acid control (GAAC) pathway, which was activated concomitant with RTD, resulting in further tRNA loss. We now find that another class of S. pombe trm8Δ suppressors have mutations in rpl genes, encoding 60S subunit proteins, and that suppression occurs with minimal restoration of tRNA levels and reduced GAAC activation. Furthermore, trm8Δ suppression extends to other mutations in the large or small ribosomal subunit. We also find that S. pombe tan1Δ mutants, lacking 4-acetylcytidine, are temperature sensitive due to RTD, that one class of suppressors have rpl mutations, associated with minimal restoration of tRNA levels, and that suppression extends to other rpl and rps mutations. However, although S. pombe tan1Δ temperature sensitivity is associated with some GAAC activation, suppression by an rpl mutation only modestly inhibits GAAC activation. We propose a model in which ribosomal protein mutations result in reduced ribosome concentrations, leading to both reduced ribosome collisions and a reduced requirement for tRNA, with these effects having different relative importance in trm8Δ and tan1Δ mutants. This model is consistent with our results in S. cerevisiae trm8Δ trm4Δ mutants, known to undergo RTD, fueling speculation that this model applies across eukaryotes.

USE OF THE rpl32-trnL REGION OF THE CHLOROPLAST GENOME IN THE MOLECULAR TAXONOMY OF HERACLEUM SPECIES

In recent decades, the invasion of alien plant species has acquired the status of one of the greatest threats to biodiversity. Invasive plants can not only displace native species but also transform ecosystems, which leads to more global negative consequences. An additional danger is the hybridization of invasive species with closely related native plants, which can contribute to the emergence of more aggressive invasive forms. The territory of Ukraine is also actively colonized by alien plants, among which the group of giant borschts (Heracleum, Apiaceae) attracts special attention. In addition to the impact on ecosystems, these plants are dangerous for people, because they can cause photochemical burns when in contact with the skin. For one of the species of this group, namely H. mantegazzianum Sommier & Levier, the possibility of hybridization with the aboriginal European species H. sphondylium L. However, both parental species and potential hybrid forms from the territory of Ukraine remain unexplored using molecular genetic methods. In this work, for the first time, we amplified and sequenced the spacer region of the chloroplast genome between the rpl32 and trnL genes for samples of H. mantegazzianum and H. sphondylium. The obtained sequences were compared with each other and with rpl32-trnL sequences available in the GenBank database for other species of the genus Heracleum. Phylogenetic analysis showed that the use of the rpl32-trnL region allows dividing all species of the genus into two main groups, one of which includes H. mantegazzianum and H. sphondylium Thus, the rpl32-trnL site can be successfully used for molecular identification of Ukrainian representatives of the genus Heracleum, as well as for determining the direction of hybridization for potential hybrid forms between the invasive species H. mantegazzianum and the native representative of the Ukrainian flora H. sphondylium. Key words: bioinformatic analysis, genetic polymorphism, molecular markers, molecular genomics, rpl32-trnL intergenic spacer, interspecific hybridization, Heracleum, Apiaceae.

Exploring the chloroplast genomics, comparative analysis, evolution, and phylogenetic relationships of Phylica pubescens (Rhamnaceae) in the Cape Flora

Phylica (Rhamnaceae) plants are mainly distributed in southern Africa and nearby islands. They play a crucial role in studying diversification rates, climate change, and vegetation evolution in the Cape Flora. However, there have been no reports on the complete chloroplast genome of Phylica species, which is essential for investigating evolution and phylogenetic relationships. Herein, we sequenced the complete chloroplast genome of Phylica pubescens and conducted a comparative analysis with 12 Rhamnaceae species. The chloroplast genome size of Phylica pubescens was 161,187 bp, similar to that of other Rhamnaceae species. The absence of infA and psbL genes in certain Rhamnaceae species, compared to Phylica pubescens, has no apparent impact on these species. Positive selection has been observed in the rpl32, psbK, and psbH genes of Rhamnaceae species. Some highly variable regions (trnH-GUG–psbA, trnK-UUU–rps16, rps16–trnQ-UUG, trnS-GCU–trnG-UCC, trnR-UCU–atpA, atpH–atpI, trnC-GCA–petN, trnT-GGU–psbD, psbZ–trnG-GCC, trnT-UGU–trnL-UAA, ndhC–trnV-UAC, accD–psaI, petA–psbJ, ndhF–rpl32, and rpl32–trnL-UAG) were identified, which might be useful for phylogenetic analysis. Based on complete chloroplast genomes for the greatest number of species, the phylogenetic tree of the Rhamnaceae was reconstructed. Phylica pubescens displayed a close phylogenetic relationship with Spyridium species. This study provides valuable information regarding the complete chloroplast genome of Phylica pubescens and its comparative analysis with other Rhamnaceae species. These findings enhance our knowledge of the evolution within the Rhamnaceae family and shed light on the relationships between Phylica pubescens and closely related taxa.

Insight into chloroplast genome structural variation of the Mongolian endemic species Adonis mongolica (Ranunculaceae) in the Adonideae tribe

Adonis mongolica is a threatened species that is endemic to Mongolia. It is a medicinal plant from the Adonis genus and has been used to treat heart diseases. However, the genomics and evolution of this species have not been thoroughly studied. We sequenced the first complete plastome of A. mongolica and compared it with ten Adonideae species to describe the plastome structure and infer phylogenetic relationships. The complete plastome of A. mongolica was 157,521 bp long and had a typical quadripartite structure with numerous divergent regions. The plastomes of Adonideae had relatively constant genome structures and sizes, except for those of Adonis. The plastome structure was consistent across Adonis. We identified a 44.8 kb large-scale inversion within the large single-copy region and rpl32 gene loss in the Adonis plastomes compared to other members of the Adonideae tribe. Additionally, Adonis had a smaller plastome size (156,917–157,603 bp) than the other genera within the tribe (159,666–160,940 bp), which was attributed to deletions of intergenic regions and partial and complete gene losses. These results suggested that an intramolecular mutation occurred in the ancestor of the Adonis genus. Based on the phylogenetic results, Adonis separated earlier than the other genera within the Adonideae tribe. The genome structures and divergences of specific regions in the Adonis genus were unique to the Adonideae tribe. This study provides fundamental knowledge for further genomic research in Mongolia and a better understanding of the evolutionary history of endemic plants.