The genus Lirianthe in the family Magnoliaceae includes approximately 25 species, each with exceptional landscaping and horticultural or medical worth. Many of these plants are considered rare and protected due to their endangered status. The limited knowledge of species within this genus and the absence of research on its chloroplast genome have greatly impeded studies on the relationship between its evolution and systematics. In this study, the chloroplast genomes of 8 species from the genus Lirianthe were sequenced and analyzed, their phylogenetic relationships with other genera of the family Magnoliaceae are also elucidated. The results showed that the chloroplast genome sizes of the 8 Lirianthe species ranged from 159,548 to 159,833 bp. The genomes consisted of a large single copy region, a small single copy region, and a pair of inverted repeat sequences. The GC content was very similar across species. Gene annotation revealed that the chloroplast genomes contained 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes, totaling 130 genes. Codon usage analysis indicated that codon usage was highly conserved among the 8 Lirianthe species. Repeat sequence analysis identified 42-49 microsatellite sequences, 16-18 tandem repeats, and 50 dispersed repeats, with microsatellite sequences being predominantly single nucleotide repeats. DNA polymorphism analysis revealed 10 highly variable regions located in the large single copy and small single copy regions, among which rpl32-trnL, petA-psbJ and trnH-psbA are recommended candidate DNA barcodes for the genus Lirianthe species. The inverted repeat boundary regions show little variation between species and are generally conserved. Phylogenetic tree analysis confirmed the monophyly of the genus Lirianthe and its closest relationship with the genera, Talauma and Dugandiodendron. Morphological studies found noticeable differences between Lirianthe species in aspects including leaf indumentum, stipule scars, floral orientation, tepal number, tepal texture, and fruit dehiscence. In summary, this study elucidated the chloroplast genome evolution within Lirianthe and laid a foundation for further systematic and taxonomic research of this genus.

Dendrobium Sw have multiple photosynthetic pathways but due to the lack of identification, the influence of CAM pathway on the plastid genomic evolution of Dendrobium and the origin of CAM pathway are still poorly understood. In this study, based on the results of δ13C, net photosynthetic rates (Pn) and titratable acid value, we identified Dendrobium species into three photosynthetic pathways. Then the chloroplast whole genome characteristics of 10 Dendrobium species were analyzed with next-generation sequencing technology. The quadripartite-structure plastomes ranged from 151,673 bp to 160,375 bp and included 127 to 132 genes. Five noncoding mutational hotspots (rbcL-accD, atpB-rbcL, rbcL, trnLUAA, accD, Pi > 0.10) were identified. A total of 41–60 SSRs were recognized, the average trinucleotide content was only about 4%, which is probably due to a more conserved SSR. Among multiple photosynthetic pathways, the apparent differences in IR junctions of SSC/IRB junctions (JSBs) were measured within chloroplast genomes, and the chloroplast genome size of constitutive CAM plants is shorter because of their ndh gene loss or pseudogenization, and this phenomenon accounts for a decreasing proportion of constitutive CAM, facultative CAM, and obligate C3 plants, so that the loss of the ndh gene may be speculated to be closely related to the CAM pathway. Phylogenetic analyses showed that there are multiple independent CAM origins in selected Dendrobium species, and the ancestral Dendrobium plastome possessed full ORFs for all ndh genes. The study aims to clarify the chloroplast genomic features of different photosynthetic pathways, enrich the genomic data of CAM plants, and provide genetic information from different perspectives for further systematic study of Dendrobium.

Capirona (Calycophyllum spruceanum Benth.) belongs to subfamily Ixoroideae, one of de major lineages in the Rubiaceae family, and is an important timber tree, with origin in the Amazon Basin and has widespread distribution in Bolivia, Peru, Colombia, and Brazil. In this study, we obtained the first complete chloroplast (cp) genome of capirona from department of Madre de Dios located in the Peruvian Amazon. High-quality genomic DNA was used to construct librar-ies. Pair-end clean reads were obtained by PE 150 library and the Illumina HiSeq 2500 platform. The complete cp genome of C. spruceanum has a 154,480 bp in length with typical quadripartite structure, containing a large single copy (LSC) region (84,813 bp) and a small single-copy (SSC) region (18,101 bp), separated by two inverted repeat (IR) regions (25,783 bp). The annotation of C. spruceanum cp genome predicted 87 protein-coding genes (CDS), 8 ribosomal RNA (rRNA) genes, 37 transfer RNA (tRNA) genes and 01 pseudogene. A total of 41 simple sequence repeats (SSR) of this cp genome were divided into mononucleotides (29), dinucleotides (5), trinucleotides (3), and tetranucleotide (4). Most of these repeats were distributed in the noncoding regions. Whole chloroplast genome comparison with the other six Ixoroideae species revealed that the small single copy and large single copy regions showed more divergence than invert regions. Finally, phylogenetic analysis resolved that C. spruceanum is a sister species to Emmenopterys henryi, and confirms its position within the subfamily Ixoroideae. This study reports for the first time the genome organization, gene content, and structural features of the chloroplast genome of C. spruceanum, providing valuable information for genetic and evolutionary studies in the genus Calycophyllum and beyond.

Cleomaceae is an important group that is medicinally and economically important. However, its systematic position has been controversial. In this study, we have obtained three chloroplast genomes sequencing results of Cleomaceae species. The genome sizes ranged from 157,073 bp (Sieruela rutidosperma) to 158,152 bp (Gynandropsis gynandra). These chloroplast genomes have a typical quadripartite formation with a large single-copy (LSC) region (86,422-87,242bp), a small single-copy (SSC) region (18,485-18,548bp), and a pair of inverted repeat (IR) regions (26,083-26,184bp). The chloroplast genomes encoded 131-132 genes, comprising 8 rRNA genes, 37 tRNA genes, and 79-84 protein-coding genes. The overall GC contents of the three chloroplast genomes are almost identical (35.81%-36.02%). The phylogenetic trees concluding 8 Cleomaceae plants were constructed based on ML and BI methods. The results showed that Gynandropsis gynandra and Sieruela rutidosperma were in the same branch, with Corynandra viscosa as their sister. Six hypervariable areas were identified, containing clpP, matK, ndhF, atpH-atpI, atpF-atpH and petN-psbM which could be used in species identification and population genetics studies. This study provides valuable information for further species identification, evolutionary and genetic studies of Cleomaceae in the future.

Bulbophyllum is one of the largest genera and presents some of the most intricate taxonomic problems in the family Orchidaceae, including species of ornamental and medical importance. The lack of knowledge regarding the characterization of Bulbophyllum chloroplast (cp) genomes has imposed current limitations on our study. Here, we reported the complete cp genomes of seven Bulbophyllum species, including B. ambrosia, B. crassipes, B. farreri, B. hamatum, B. shanicum, B. triste and B. violaceolabellum, and compared with related taxa to provide a better understanding of their genomic information on taxonomy and phylogeny. A total of 28 Bulbophyllum cp genomes exhibit typical quadripartite structures with lengths ranging from 145,092 bp to 165,812 bp and GC content of 36.60% to 38.04%. Each genome contained 125–132 genes, encompassing 74–86 protein-coding genes, 38 tRNA genes, and eight rRNA genes. The genome arrangements, gene contents and length were similar with differences observed in ndh gene composition. A total of 18–49 long repeats and 38–80 simple sequence repeats (SSRs) were detected and the single-nucleotide (A/T) was dominant in Bulbophyllum cp genomes, with an obvious A/T preference. An analysis of relative synonymous codon usage (RSCU) revealed Leucine (Leu) was the most frequently used codon, while cysteine (Cys) was the least used. Six highly variable regions including ndhF-trnLUAG, trnTUGU-trnLUAA, trnFGAA-ndhJ, rps15-trnNGUU, rbcL-accD and psbI-trnSGCU were identified based on the ranking of the Pi values, had the potential to serve as DNA markers for species identification and phylogeny of the genus Bulbophyllum. Phylogenetic analysis based on the complete cp genome sequences and 68 protein-coding genes strongly supported 28 Bulbophyllum species can be divided into four branches and sects. Brachyantha, Cirrhopetalum, Leopardinae defined by morphology were non-monophyly. Our results enriched the genetic resources of Bulbophyllum species, providing valuable information to illustrate the complicated taxonomy, phylogeny and evolution process of the genus.

Sphingolipids are ubiquitous in eukaryotes and certain prokaryotes, where they serve as vital components of biological membranes and as bioactive molecules. Chloroplasts have complex membrane structures that play crucial roles in photosynthesis, but their specific sphingolipidome remains unreported. In this study, we used high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) to analyze the sphingolipidome of purified Arabidopsis thaliana chloroplasts. We detected 92 chloroplast sphingolipids. The chloroplast sphingolipidome differed from total leaf (TL) samples, having a higher content of free long-chain bases and hydroxyceramides, and a greater proportion of complex sphingolipids with 16C fatty acid (FA) forms. Notably, chloroplast glucosylceramides were predominantly the d18:1 h16:0 and t18:1 h16:0 forms, rather than the 24C FA form found in TL and other cellular structures. Comparing the sphingolipidomes of different cellular structures underscores the inhomogeneity of intracellular distribution of sphingolipids. This provides a robust reference for further elucidating the function of sphingolipids in plant cells.

In our article in Genome Biology Ecology six years ago, one complete plastid genome of Belian was assembled for comparative analyses of the plastomes in Lauraceae. However, Ariati et al. (2023) concluded that our sequenced Belian individual could be located in the clade of Myristicaceae instead of that of Lauraceae. Here, we performed re-analyses of additional two Belian plastomes, along with 42 plastomes from plants spanning ten families of the Magnoliids. The plastomes of the three Belian individuals range from 157,535 to 157,577 bp in length. Comparative genomic analysis revealed 170 mutation sites in their plastomes, which include 111 substitutions, 53 indels, and six microinversions. Phylogeny was reconstructed using maximum likelihood and Bayesian approaches for 44 magnoliids species indicated that our three Belian individuals are nested among the species in the family Lauraceae rather than Myristicaceae.

Cycas (family Cycadaceae), spread throughout tropical and subtropical regions, is crucial in con-servation biology. Due to the subtle morphological variations between species, a solid spe-cies-level phylogeny for Cycas is lacking. Because of the rapid progress in high-throughput se-quencing technology, it has become feasible to acquire complete chloroplast (cp) genome se-quences, which provide a molecular foundation for phylogenetic research. In the present study, we employed next-generation sequencing technology to assemble and analyze the chloroplast genomes of six Cycas plants, including their genome structure, GC content, and nucleotide di-versity. The Cycas chloroplast genome spans 162,038 to 162,159 bp and contains 131 genes, in-cluding 86 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Through a comparative analysis, we found that the chloroplast genome of Cycas was highly conserved, as indicated by the contraction and expansion of the inverted repeat (IR) re-gions and sequence polymorphisms. In addition, several non-coding sites (psbK-psbI, petN-psbM, trnE-UUC-psbD, ndhC-trnM-CAU, and rpl32-trnP-GGG) showed significant varia-tion. The utilization of phylogenetic analysis relying on protein-coding genes has substantiated the division of Cycas primarily into four groups. The application of these findings will prove valuable in evaluating genetic diversity and the phylogenetic connections among closely related species. Moreover, it will provide essential support for the advancement of wild germplasm re-sources.

Abstract: Chloroplast is a new hotspot in the field of plant transformation system of plant genetic engineering. Initially developed in Chlamydomonas and tobacco, it is now feasible in a broad range of species. They exploit the homologous recombination and segregation pathways acting on chloroplast genomes and are based on direct repeats, transient co-integration or co-transformation and segregation of trait and marker genes. Foreign site-specific recombinases and their target sites provide an alternative and effective method for removing marker genes from plastids.Chloroplast genetic engineering has many advantages over nuclear genetic enginering, especially site-specific introduction of foreign genes ,leading to the absence of gene siliency and positon effect,which providing the available to explore the regulation and mechanism of chloroplast genes`expression in vitro .It also can identify the structure and function of the chloroplast genome , the expression of chloroplast affect the nulear genome. In this paper, the basic methodology of chloroplast transformation, the current techniques and applications, and the future possibilities for Chloroplast genetic engineering was reviewed[1-3].

Chloroplasts are ancient organelles responsible for photosynthesis and various biosynthetic functions essential to most life on Earth. Many of these functions require tightly controlled regulatory processes to maintain homeostasis at the protein level. One such regulatory mechanism is the ubiquitin-proteasome system whose fundamental role is increasingly emerging in chloroplasts. In particular, the role of E3 ubiquitin ligases as determinants in the ubiquitination and degradation of specific intra-chloroplast proteins. Here, we highlight recent advances in understanding the roles of plant E3 ubiquitin ligases in chloroplast function.

Sweet cucumber (Solanum muricatum) sect. Basarthrum, is a neglected horticultural crop native of the Andean region. It is naturally distributed very close to potatoes (Solanum sect. Petota) and tomatoes (Solanum sect. Lycopersicon), two groups of high economic importance. To date, molecular tools for this crop are still undetermined. We here obtained the first complete chloroplast (cp) genome of sweet cucumber and compared with seven Solanaceae species. Pair-end clean reads were obtained by PE 150 library and the Illumina HiSeq 2500 platform. The complete cp genome of S. muricatum had a 155,681 bp with typical quadripartite structure, containing a large single copy (LSC) region (86,182 bp) and a small single-copy (SSC) region (18,360 bp), separated by two inverted repeat (IR) regions (25,568 bp). The annotation of chloroplast genome predicted 88 protein-coding genes (CDS), 8 ribosomal RNA (rRNA) genes, 37 transfer RNA (tRNA) genes, and one pseudogene. A total of 48 perfect microsatellites were identified, divided in mononucleotide repeats (32), followed by tetranucleotide (6) and dinucleotides (5). SSRs with trinucleotides repeats (3), pentanucleotide (1) and hexanucleotide (1) repeats motifs in these genomes were identified in lower quantity. Most of these repeats were distributed in the noncoding regions. Whole chloroplast genome comparison with the other seven Solanaceae species revealed that the small and large single copy regions showed more divergence than inverted regions. Finally, phylogenetic analysis resolved that S. muricatum is a sister species to members of sections Petota + Lycopersicum + Etuberosum. This study reports for the first time the genome organization, gene content, and structural features of the cp genome of S. muricatum. Also, this study may provide the basis for evaluating genetic diversity within Solanum, and will be useful to examine the evolutionary processes in sweet cucumber landraces.

Plastid genomes are in general highly conserved given their slow evolutionary rate, thus large changes in their structure are unusual. However, when specific rearrangements are present, they are often phylogenetically informative. Asteraceae is a highly diverse family whose evolution is long driven by polyploidy (up to 48x) and hybridisation, both processes usually complicating systematic inferences. In this study, we have generated one of the most comprehensive plastome-based phylogenies of family Asteraceae, providing information about the structure, genetic diversity, and repeat composition of these sequences. By comparing the whole plastome sequences obtained, we confirmed the double inversion located in the long single copy region, for most of the species analysed (with the exception of basal tribes), a well-known feature for Asteraceae plastomes. We also show that genome size, gene order and gene content are highly conserved along the family. However, species representative of the basal subfamily Barnadesioideae -as well as in the sister family Calyceraceae - are lacking the pseudogene rps19 located in one inverted repeat. The phylogenomic analysis conducted here, based on 63 protein-coding genes, 30 transfer RNA genes and 21 ribosomal RNA genes from 36 species of Asteraceae, are overall consistent with the general consensus for the family’s phylogeny, while resolving the position of tribe Senecioneae and revealing some incongruences at tribe level between reconstructions based on nuclear and plastid DNA data.

The present study provides a detailed analysis of the chloroplast genome of Microula sikkimensis. The genome was consisted of altogether 149,428bp and distinct regions, including large single-copy (81329bp), small single-copy (17261bp), and inverted repeat (25419bp). The genome contained 112 genes, including 78 protein-coding genes, 30 tRNA genes, and 4 rRNA genes, some exhibited duplication in the IR region. The chloroplast genome displayed different GC content across regions, with the IR region exhibiting the highest. Codon usage analysis and the identification of simple sequence repeats (SSRs) offer valuable genetic markers. Comparative analysis with other Boraginaceae species highlighted conservation and diversity in coding and noncoding regions. Phylogenetic analysis placed M. sikkimensis within the Boraginaceae family, revealing its distinct relationship with specific species.

Poro-poro is an important native fruit used in traditional Peruvian medicine with relevant agro-industrial and pharmaceutical potential for its antioxidant capacity for human health. However, to date, there have been few genetic studies. The lack of genomic exploration limits the possibility of expanding our knowledge of its molecular evolution, new molecular pathways, genetic traits, and evolutionary relationships. Here, we report the plastid genome sequence of Passiflora tripartita var. mollissima and the reconstructed phylogenetic tree to infer the phylogenetic relationships among Passiflora species. Our phylogenetic analysis showed that poro-poro is most closely related to Passiflora menispermifolia and Passiflora oerstedii. In summary, our study provides the basis for developing new molecular markers that constitutes a valuable resource for studying molecular evolution and domestication. It also provides a powerful foundation for conservation genetics research and plant breeding programs. To our knowledge, this is the first report on the plastid genome of Passiflora tripartita var. mollissima from Peru.

Garcinia indica (Thouars) Choisy (commonly known as Kokum) is an important medicinal plant in Ayurvedic medicine and belonging to the Clusiaceae family. Kokum is a highly traded medicinal plant species of India, dried rind of fruits and butter from seeds are traded in the markets. This study aimed to assemble the complete chloroplast (cp) genome of G. indica and compare it with the previously published cp genome within the Garcinia taxa to identify the potential species-specific barcode marker for Kokum authentication. The assembled cp genome, with a size of 1,56,891 bp, exhibits a typical quadripartite structure. The large single-copy (LSC) region spans 85,580 bp, and the small single-copy (SSC) region spans 17,181 bp, together comprising 64.5% of the genome. The pair of inverted repeats (IRA and IRB) are each 27,065 bp, covering the remaining 35.5% of the genome. A total of 126 unique genes were identified, including 86 protein-coding genes, 32 tRNA genes, and 8 rRNA genes. Phylogenetic analysis using complete cp genomes from 12 species in the Clusiaceae family indicated that 10 Garcinia species form a sister clade. Notably, the ycf1 gene in the LSC region was more divergent within the Garcinia species. This study presents the first report on the chloroplast genome of G. indica. This chloroplast genome resource provides a basis for identifying new DNA barcode marker as well as species-specific marker for herbal drug authentication of Kokum, and species delineation within the Garcinia genus.

Core chlorophytes possess glycerol-3-phosphate dehydrogenases (GPDs) with an unusual bidomain structure, consisting of a glycerol-3-phosphate phosphatase (GPP) domain fused to canonical GPD domains. These plastid-localized enzymes have been implicated in stress responses, being required for the synthesis of glycerol under high salinity and triacylglycerols under nutrient deprivation. However, their regulation under varying environmental conditions is poorly understood. C. reinhardtii transgenic strains expressing constitutively bidomain GPD2 did not accumulate glycerol or triacylglycerols in the absence of any environmental stress. Although, the glycerol contents of both wild type and transgenic strains increased significantly upon exposure to high salinity. Cycloheximide, an inhibitor of cytoplasmic protein synthesis, abolished this response in the wild type. In contrast, GPD2 transgenic strains were still capable of glycerol accumulation when cultured in medium containing cycloheximide and NaCl. Thus, pre-existing GPD2 protein appears to become activated for glycerol synthesis upon salt stress. Interestingly, staurosporine, a non-specific inhibitor of protein kinases, prevented this post-translational GPD2 protein activation. Structural modeling analyses suggested that substantial conformational rearrangements, possibly triggered by high salinity, may characterize an active GPD2 GPP domain. Understanding this mechanism(s) may provide insights into the rapid acclimation responses of microalgae to osmotic/salinity stress.

Vernonia amygdalina is an important nutritional and medicinal plant that is used to treat various diseases such as malaria and diabetes in Nigeria. In this study, we sequenced, assembled, and annotated the complete nucleotide sequence of the chloroplast genome of a V. amygdalina species isolated in Awka, Nigeria. The chloroplast genome is 153 149 bp in length and has a conserved structure that includes the LSC (84261 bp) region, the SSC (13152 bp) region, and the IR (27868 bp) regions. A total of 131 genes were identified, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Comparative analysis of the genome revealed species variations in the LSC region associated with the geographical location of the V. amygdalina plant. Phylogenetic analysis of the chloroplast genomes using FastTree showed that V. amygdalina clustered closest to the chloroplast of the Crepidiastrum genus. This study identifies the characteristics of the V. amygdalina chloroplast genome, which will improve our understanding of intraspecies diversity and the identification of potential molecular markers to determine geographical origin.

Peanut (Arachis hypogaea) contains allergenic proteins, which make it harmful to the sensitised population. The presence of peanut in foods must be indicated on label, to prevent accidental consumption by allergic population. In this work, we use chloroplast markers for specifically detection of peanut by real-time PCR, in order to increase the assay sensitivity. Binary mixtures of raw and processed peanut flour in wheat were performed at concentrations ranging from 100000 to 0.1 mg/kg. DNA isolation from peanut, mixtures and other legumes was carried out following three protocols for obtaining genomic and chloroplast-enrich DNA. Quantity and quality of DNA was evaluated, obtaining better results for protocol 2. Specificity and sensitivity of the method has been assayed with specific primers for three chloroplast markers (mat k, rpl16 and trnH-psbA) and Ara h 6 peanut allergen-coding region was selected as nuclear low-copy target and TaqMan probes. Efficiency and linear correlation of calibration curves were within the adequate ranges. Mat k chloroplast marker yielded the most sensitive and efficient detection for peanut. Moreover, detection of mat K in binary mixtures of processed samples was possible up to 10 mg/kg even after boiling, and autoclave 121°C 15 min, with acceptable efficiency and linear correlation. Applicability of the method has been assayed in several commercial food products.

The order Nymphaeales, consisting of three families with a record of eight genera, has gained significant interest from botanists probably due to its position as a basal-angiosperm. The phylogenetic relationships within the order have well been studied and resolved; however, a few controversial nodes still remain in the Nymphaeaceae including the position of the genus Nuphar. The position of the genus Nuphar and the monophyly of the Nymphaeaceae family remain uncertain. This study adds to the increasing number of completely sequenced plastid genomes of the Nymphaeales and applies large chloroplast gene data set in reconstructing the intergeneric relationships within the Nymphaeaceae. Five complete chloroplast genomes were newly generated, including a first one for the monotypic genus Euryale. Using a set of 66 protein coding genes from the chloroplast genomes of 17 taxa, the phylogenetic position of Nuphar was determined and a monophyletic Nymphaeaceae family was obtained with a convincing statistical support from both partitioned and unpartitioned data schemes. Although genomic comparative analyses revealed a high degree of synteny among the chloroplast genomes of the ancient angiosperms, key minor variations were evident particularly in the contraction/expansion of the Inverted Repeat regions and in RNA editing events. Genome structure, gene content and arrangement were highly conserved among the chloroplast genomes.

Genus Clematis is one of the largest within Ranunculaceae. Here we report the chloroplast genome of two Clematis species, C. brachyura and C. trichotoma endemic to Korea. The chloroplast genome lengths of C. brachyura and C. trichotoma are 159,532 bp and 159,170 bp, respectively. Gene contents in the complete chloroplast genomes of these two Clematis species are identical to that of most Ranunculaceae and other angiosperms. However, our data results demonstrated that genus Clematis has inversion and rearrangement events concerning gene rps4 gene, rps16 to trnH region, and trnL to ndhC region, and IR regions expansion. Comparison of IR regions among Ranunculaceae species revealed that Clematis species contained six protein coding genes (infA, rps8, rpl14, rpl16, rps3, and rpl22) usually found in the long single copy (LSC) region of other species. Phylogenetic analysis demonstrated that genus Clematis is closely related to genus Ranunculus. Differences in repeat structure, substitution rates, and IR expansion in genera Clematis and Ranunculus, explained their relationship. Clematis species showed slightly higher tandem repeats content than Ranunculus species. The six protein-coding genes showed lower synonymous substitution rates in the IR of Clematis species than in the LSC of Ranunculus species. Overall, the chloroplast genomes and results presented here provide important information on the evolution of Ranunculaceae.

The genus Fritillaria belongs to the widely distributed family Liliaceae. The bulbs of Fritillaria ussuriensis and Fritillaria cirrhosa are valuable herbaceous medicinal ingredients. However, they are still used indiscriminately in herbal medicine. Identification and molecular phylogenic analysis of Fritillaria species is therefore required. Here, we report the complete chloroplast (cp) genome sequences of F. ussuriensis and F. cirrhosa. The two Fritillaria cp genomes were 151,524 and 151,083 bp in length, respectively, including a pair of inverted repeat regions (52,678 and 52,156 bp) separated by a large single copy region (81,732 and 81,390 bp) and small single copy region (17,114 and 17,537 bp). A total of 111 genes in F. ussuriensis and 112 in F. cirrhosa comprised 77 protein-coding genes in F. ussuriensis and 78 in F. cirrhosa, 30 tRNA genes, and four rRNA genes. The gene order, content, and orientation of the two Fritillaria cp genomes exhibited the general structure of flowering plants, and were similar to those of other Fritillaria species. Comparison of the six Fritillaria species’ cp genomes indicated seven highly divergent regions in intergenic spacers and in the matK, rpoC1, rpoC2, ycf1, ycf2, ndhD, and ndhF coding regions. We established the position of the six species through phylogenic analysis. The complete chloroplast genome sequences of two Fritillaria species will be useful genomics resources for identification of Fritillaria species and for studying the phylogenetic relationship among Fritillaria species within the Liliaceae family.

: This study focuses on optimizing chlorophyll extraction techniques and strategically placing leaf disks to enhance chlorophyll concentration in sesame (Sesamum indicum L.) leaves. Thirty sesame genotypes, categorized into light green (LG), middle green (MG), and deep green (DG) pigment groups based on leaf coloration, were selected from a larger pool of field-grown accessions. The investigation involved determining optimal SPAD value index measurements, quantifying pigment concentrations, exploring extraction solvents, and selecting suitable leaf disk positions. Significant variations in chlorophyll content were observed across genotypes, greenness categories, and leaf disk positions. The categorization of genotypes into DG, MG, and LG groups revealed a correlation between leaf appearance and chlorophyll content. The study highlighted a consistent relationship between carotenoids and chlorophyll, indicating their role in adaptation to warm environments. Examination of leaf disk positions revealed a significant chlorophyll gradient along the leaf blade, emphasizing the need for standardized protocols. Chlorophyll extraction experiments identified DMSO and 96% ethanol, particularly the later incubated for 10 minutes at 85°C, as effective choices. This recommendation considers factors like cost-effectiveness, time efficiency, safety, and environmental regulations, ensuring consistent and simplified extraction processes. For higher chlorophyll extraction, focusing on leaf tips and the 75% position along the sesame leaf blade is suggested, consistently yielding higher chlorophyll content. Our findings therefore, underscores insightful knowledge on chlorophyll gradients and encouraging for standardized protocols, that enabling researchers to refine experimental designs for precise and comparable chlorophyll measurements. Recommended solvent choices ensure reliable outcomes in plant physiology, ecology, and environmental studies.

The chloroplast is important organelle responsible for photosynthesis and various bio- synthetic functions essential to green plants. However, the regulatory mechanism of chloroplast development remains elusive. Here, we characterized a mutant with defective chloroplasts in rice (Oryza sativa L.) named it albino and lethal 13(osal13), which exhibited a distinct albino phenotype in leaves, eventually leading to seedling lethality. Molecular cloning revealed that OsAL13 encodes a novel protein in rice for which no homologous gene or known conserved domain was found. Analysis of the biological characteristics showed that the RNAi2 leaf was completely albino phenotype, the root and shoot lengths were significantly inhibited compared with wild type. Transmission electron microscopy indicated that RNAi2 were defective in chloroplast development. Overexpression of OsAL13 resulted the photosynthetic rate increase, So the total grain number per panicle also would be significantly increase. Besides, OsAL13 was located in chloroplast and constitutively expressed in various tissues, including green and non-green tissues. In addition, disruption of OsAL13 resulted in altered expression of plastid-encoded polymerases and nuclear-encoded chloroplast genes, OsAL13 also affected hormone levels in plant tissues. Therefore, our results provide new insights into the role of OsAL13 in regulating chloroplast development in rice.

Within the family Solanaceae, Withania is a small genus belonging to the Solanoideae subfamily. Here, we report the de novo assembled, complete, plastomed genome sequences of W. coagulans, W. adpressa, and W. riebeckii. The length of these genomes ranged from 154,198 base pairs (bp) to 154,361 bp and contained a pair of inverted repeats (IRa and IRb) of 25,027--25,071 bp that were separated by a large single-copy (LSC) region of 85,675--85,760 bp and a small single-copy (SSC) region of 18,457--18,469 bp. We analyzed the structural organization, gene content and order, guanine-cytosine content, codon usage, RNA-editing sites, microsatellites, oligonucleotide and tandem repeats, and substitutions of Withania plastid genomes, which revealed close resemblance among the species. Both the substitution and insertion and deletion analyses confirmed that the IR region was significantly conserved compared with the LSC and SSC regions. Further comparative analysis among the Withania species highlighted 30 divergent hotspots that could potentially be used for molecular marker development, phylogenetic analysis, and species identification.

Hippophae is a tree species with ecological, economic and social benefits. In this study, we assembled and annotated chloroplast genomes of sympatric Hippophae gyantsensis and H. rhamnoides subsp. yunnanensis. Their full-length are 155260 and 156415 bp, respectively. Each of them has 131 genes, comprising 85 protein-coding genes, 8 ribosomal RNA genes and 38 transfer RNA genes. After comparing the chloroplast genomes, we found 1302 base difference loci, and 63.29% are located in the intergenic region or intron sequences and 36.71% are located in the coding sequences. The SSC region has the highest mutation rate, followed by the LSC region; the IR regions have the lowest mutation rate. Among the protein-coding genes, three had a ratio of nonsynonymous to synonymous substitutions (Ka/Ks) >1 (but P values were non-significant) and 66 had Ka/Ks <1 (46 were significant). In general, the chloroplast protein-coding genes may be subject to purification selection. Among H. gyantsensis and H. rhamnoides subsp. yunnanensis chloroplast protein-coding genes, there are 20 and 16 optimal codons, respectively. Most of the optimal codons were ending with A or U, which indicates significant AT preference. It is an important reference for studies on the general characteristics and evolution of the Hippophae chloroplast genome.

Habenaria, a member of Orchidaceae family is the cosmopolitan distributions, which has significant medicinal and ornamental values. Regardless of morphology and molecular data that have been studied in recent times, the phylogenetic relationship is still under debate. Here, we sequenced, assembled, and annotated the whole chloroplast (cp) genome of two species (Habenaria aitchisonii Rchb.f. and Habenaria tibetica Schltr.ex Limpricht) of Habenaria grown on the Qinghai-Tibetan Plateau (QTP), and combined with seven already published cp genomes which may assist to uncover their genomic profiling. The two genomes ranged from 155259-155269 bp in length and both encoded 132 genes, including 86 protein, 38 tRNA and 8 rRNA. In the cp genomes, the tandem repeats (797), SSRs (2195) and diverse loci (3214) were identified. Comparative analyses of codon usage, amino frequency, microsatellite, oligo repeats and transition and transversion substitutions showed similarities among the species. Moreover, we identified 16 highly polymorphic regions with nucleotide diversity above 0.02, which may be suitable for robust authentic barcoding and inferring in the phylogeny of Habenaria species. Among the polymorphic regions, positive selection was significantly exerted on the several genes such as cemA, petA, and ycf1. This may suggest that the important adaptation stratagem for two Habenaria species on the QTP. The phylogenetic relationship displayed that H.aitchisonii and H. tibetica have closer relationship than others and the rest seven species clustered in the other three groups. Our findings also supported the idea that Habenaria could be divided into different sections. This study enriched the genomics resources of Habenaria, which may be helpful for the conservation efforts of these endangered species.

Heat stress is a serious threat to tomato production. The ultrastructure and element mapping of tomato chloroplast were investigated under different nitrogen levels to explore the regulatory effect of nitrogen on tomato chloroplast under heat stress. Experiments design two temperature treatments (25°C/15°C, as control, 40°C/30°C, as severe high-temperature, SHT ) and four nitrogen levels (0.0 kg hm-2, N1; 187.5 kg hm-2, N2; 250 kg hm-2, N3, as recommended nitrogen-application; 312.5kg hm-2 , N4) for a duration of 5 days in artificial climate chamber. The results showed that heat stress led to obvious damage to the ultrastructure of tomato chloroplast, including thylakoid stacking disorder, granum destruction, and starch grain aggregation and degradation. With the increase of nitrogen level, the ratio of long and short axes of tomato chloroplasts increased, the differentiation of chloroplasts was strengthened, the number of plastoglobuli was increased and aggregated, and the degree of damage to the ultrastructure of chloroplasts was reduced. The regulatory effect of nitrogen on the ultrastructure of tomato chloroplasts under heat stress was mainly reflected in the phosphorylation degradation process of starch granules in chloroplasts. There are obvious segmentation lines of Ca, P and Cl on both sides of the inner and outer chloroplasts, and enriched in the chloroplasts, which can outline the boundary of the chloroplasts. Element mapping analysis revealed that heat stress significantly increased the contents of calcium, phosphorus and chlorine in the chloroplast of tomato leaves, while the contents of potassium was decreased. The application of nitrogen fertilizer could significantly regulate the element distribution of tomato chloroplast under heat stress, especially the regulation of phosphorus, chlorine, calcium, magnesium. These results provide new insight into the role of nitrogen using TEM-EDX mapping in the protection of tomato chloroplast under heat stress and the mechanism of heat stress tolerance in plants.

This review deals with the adaptive mechanisms that plants can implement to cope with the challenge of salt stress. Plants tolerant to NaCl implement a series of adaptations to acclimate to salinity, including morphological, physiological and biochemical changes. These changes include increases in the root/canopy ratio and in the chlorophyll content in addition to changes in the leaf anatomy that ultimately lead to preventing leaf ion toxicity, thus maintaining the water status in order to limit water loss and protect the photosynthesis process. Furthermore, we deal with the effect of salt stress on photosynthesis and chlorophyll fluorescence and some of the mechanisms thought to protect the photosynthetic machinery, including the xanthophyll cycle, photorespiration pathway and water-water cycle. Finally, we also provide an updated discussion on salt-induced oxidative stress at the subcellular level and its effect on the antioxidant machinery in both salt-tolerant and salt-sensitive plants. The aim is to extend our understanding of how salinity may affect the physiological characteristics of plants.

The monophyly of Nymphaeaceae (water lilies) represents a critical question in understanding the evolutionary history of early-diverging angiosperms. A recent plastid phylogenomic investigation claimed new evidence for the monophyly of Nymphaeaceae, but its results could not be verified from the available data. Moreover, preliminary gene-wise analyses of the same dataset provided partial support for the paraphyly of the family. The present investigation aims to re-assess the previous conclusion of the monophyly of Nymphaeaceae under the same dataset and to determine the congruence of the phylogenetic signal across different plastome genes and data partition strategies. To that end, phylogenetic tree inference is conducted on each of 78 protein-coding plastome genes, both individually and upon concatenation, and under four data partitioning schemes. Moreover, the possible effects of various sequence variability and homoplasy metrics on the inference of specific phylogenetic relationships are tested using multiple logistic regression. Differences in the variability of polymorphic sites across codon positions are assessed using parametric and non-parametric analysis of variance. The results of the phylogenetic reconstructions indicate considerable incongruence among the different gene trees as well as the data partitioning schemes. The results of the multiple logistic regression tests indicate that the fraction of polymorphic sites of codon position 3 has a significant effect on the recovery of the monophyly of Nymphaeaceae. Taken together, these results indicate that the monophyly of Nymphaeaceae currently remains indeterminate, and that specific phylogenetic conclusions are strongly dependent on the precise plastome gene, data partitioning scheme, and codon position evaluated. In closing, I discuss the importance of archiving all data of an investigation in publicly accessible data repositories, along with sufficient details to replicate the published results, and provide recommendations on future plastid phylogenomic investigations of Nymphaeales.

The chloroplast genome is conservative and stable, which can be employed to resolve genotypes. Currently, published nuclear sequences and molecular markers failed to differentiate the species from taxa robustly, including Machilus leptophylla, Hanceola exserta, Rubus bambusarum, and Rubus henryi. In this study, the four chloroplast genomes were characterized, and then their simple sequence repeats (SSRs) and phylogenetic positions were analyzed. The results demonstrated the four chloroplast genomes consisted of 152.624 kb, 153.296kb, 156.309 kb, and 158.953 kb in length, involving 124, 130, 129, and 131 genes, respectively. Moreover, the chloroplast genomes contained typical four regions. Six classes of SSR were identified from the four chloroplast genomes, in which mononucleotide was the class with the most members. The types of the repeats were various within individual classes of SSR. Phylogenetic trees indicated that M. leptophylla was clustered with M. yunnanensis, and H. exserta was confirmed under family Ocimeae. Additionally, R. bambusarum and R. henryi were clustered together, whereas they did not belong to the same species due to the differing SSR features. This research would provide evidence for resolving the species and contributed new genetic information for further study.

As sessile organisms, plants face a wide range of abiotic stresses, with salinity being a prominent constraint affecting their growth, development, and productivity, particularly in arid and semi-arid regions. This study focused on understanding how salinity impacts Jatropha curcas, an important oilseed plant for biodiesel production. By examining the anatomy and ultrastructure of stomata and chloroplasts, we investigated the effects of prolonged salinity stress on J. curcas. This stress led to changes in stomatal density, stomatal index, and ostiole aperture, which case an imbalance of water conductivity in the xylem. Through transmission electron microscopy, we explored the subcellular organization of J. curcas chloroplasts and their contribution to plant photosynthetic efficiency, providing insights into their role in this process. Notably, salinity treatment resulted in a significant increase in starch granules accumulation, leading to impaired the granal and stromal grana lamellae, destroying this ultrastructure. Our findings indicate that the anatomy and ultrastructure of chloroplasts play a crucial role in influencing photosynthetic efficiency and hydraulic conductivity. This study offers new perspectives on the structure and function of chloroplasts in J. curcas, presenting innovative opportunities to develop strategies that enhance biofuel production in areas with high soil salinity.

Cleomella serrulata is a native flowering plant found in North America. Even though this plant is of ecological and native medicinal importance, very little is known about the genomic makeup of Cleomella and the Cleomaceae family at large. Here we report the complete chloroplast genome of Cleomella serrulata and provide an evolutionary comparison to other chloroplast genomes from Cleomaceae and closely related families. This study confirms the taxonomic placement of Cleomella as a distinct genus, but also provides phylogenetic insights that imply potential adaptive strategies and evolutionary mechanisms driving genomic diversity of the Cleomella genus. Whole genome-based and ANI comparisons indicate that the Cleomella species form a distinct clade that is about equidistant from the other Cleomaceae genera as it is from the genera from the nearby Capparaceae and Brassicaceae. This is the first complete chloroplast-based phylogenetic comparison of Cleomella species to other related genera and helps refine the complex taxonomic distinctions of the Cleomaceae.

Family Phyllanthaceae is one of the largest segregates of the eudicot order Malpighiales and its species are herb, shrub, and tree, which are mostly distributed in tropical regions. Certain taxonomic discrepancies exist at genus and family level. Here, we report chloroplast genomes of three Phyllanthaceae species—Phyllanthus emblica, Flueggea virosa, and Leptopus cordifolius— and compare them with six others previously reported Phyllanthaceae chloroplast genomes. The species of Phyllanthaceae displayed quadripartite structure, comprising inverted repeat regions (IRa and IRb) that separate large single copy (LSC) and small single copy (SSC) regions. The length of complete chloroplast genome ranged from 154,707 bp to 161,093 bp; LSC from 83,627 bp to 89,932 bp; IRs from 23,921 bp to 27,128 bp; and SSC from 17,424 bp to 19,441 bp. Chloroplast genomes contained 111 to 112 unique genes, including 77 to 78 protein-coding, 30 transfer RNA (tRNA), and 4 ribosomal RNA (rRNA) that showed similarities in arrangement. The number of protein-coding genes varied due to deletion/pseudogenization of rps16 genes in Baccaurea ramiflora and Leptopus cordifolius. High variability was seen in number of oligonucleotide repeats while analysis of guanine-cytosine (GC) content, codon usage, amino acid frequency, simple sequence repeats analysis, synonymous and non-synonymous substitutions, and transition and transversion substitutions showed similarities in all Phyllanthaceae species. We detected a higher number of transition substitutions in the coding sequences than non-coding sequences. Moreover, the high number of transition substitutions was determined among the distantly related species in comparison to closely related species. Phylogenetic analysis shows the polyphyletic nature of the genus Phyllanthus which requires further verification. We also determined suitable polymorphic coding genes, including rpl22, ycf1, matK, ndhF, and rps15 which may be helpful for the reconstruction of the high-resolution phylogenetic tree of the family Phyllanthaceae using a large number of species in the future. Overall, the current study provides insight into chloroplast genome evolution in Phyllanthaceae.

Ethylene, a gaseous phytohormone, is emerging as a central player in the intricate web of plant developmental processes from germination to senescence under optimal and stressed conditions. It is present in different plant parts, encompassing the stems, leaves, flowers, roots, seeds, and fruits. This review aims to provide a comprehensive overview of ethylene's fascinating roles in shaping various plant growth and adaptation aspects. It intricately examines the multifaceted impact of ethylene on pivotal aspects of plant development, including but not limited to cell division and elongation, senescence, abscission, fruit and flower development, root hair formation, chloroplast maturation, and photosynthesis. This comprehensive assessment encompasses the intricate pathways of ethylene biosynthesis and signaling, providing a snapshot of the regulatory mechanisms governing ethylene production. Understanding ethylene's multifaceted functions has significant implications for agriculture, biotechnology, and our fundamental comprehension of plant biology. This review underscores the need for continued investigation into ethylene's intricate mechanisms and its potential to revolutionize plant development and crop management.