DNA Extraction Protocol for Plants with High Levels of Secondary Metabolites and Polysaccharides without Using Liquid Nitrogen and Phenol

Innovative omics strategies in fermented fruits and vegetables: Unveiling nutritional profiles, microbial diversity, and future prospects

Fermented fruits and vegetables (FFVs) are not only rich in essential nutrients but also contain distinctive flavors, prebiotics, and metabolites. Although omics techniques have gained widespread recognition as an analytical strategy for FFVs, its application still encounters several challenges due to the intricacies of biological systems. This review systematically summarizes the advances, obstacles and prospects of genomics, transcriptomics, proteomics, metabolomics, and multi-omics strategies in FFVs. It is evident that beyond traditional applications, such as the exploration of microbial diversity, protein expression, and metabolic pathways, omics techniques exhibit innovative potential in deciphering stress response mechanisms and uncovering spoilage microorganisms. The adoption of multi-omics strategies is paramount to acquire a multidimensional network fusion, thereby mitigating the limitations of single omics strategies. Although substantial progress has been made, this review underscores the necessity for a comprehensive repository of omics data and the establishment of universal databases to ensure precision in predictions. Furthermore, multidisciplinary integration with other physical or biochemical approaches is imperative, as it enriches our comprehension of this intricate process.

Chromosome-scale genome assembly of the mangrove climber species Dalbergia candenatensis

Consisting of trees, climbers and herbs exclusively in the intertidal environments, mangrove forest is one of the most extreme and vulnerable ecosystems of our planet and has long been of great interest for biologists and ecologists. Here, we first assembled the chromosome-scale genome of a climber mangrove plant, Dalbergia candenatensis. The assembled genome size is approximately 474.55 Mb, with a scaffold N50 of 48.1 Mb, a complete BUSCO score of 98.4%, and a high LTR Assembly Index value of 21. The genome contained 283.46 Mb (59.74%) repetitive sequences, and 29,554 protein-coding genes were predicted, of which 87.54% were functionally annotated in five databases. The high-quality genome assembly and annotation presented herein provide a valuable genomic resource that will expedite genomic and evolutionary studies of mangrove plants and facilitate the elucidation of molecular mechanisms underlying the salt- and water-logging-tolerance of mangrove plants.

Comparison of DNA extraction methods for genotyping equine histidine-rich glycoprotein insertion/deletion polymorphisms using oral mucosa swabs and feces

Previously, we demonstrated unique insertion/deletion polymorphisms of equine histidine-rich glycoprotein (eHRG) with five genotypes composed of 45-bp or 90-bp deletions in the histidine-rich region of eHRG in Thoroughbred horses. Although leukocytes are typically used to collect DNA for genotyping, blood sampling from animals is sometimes difficult and invasive. Moreover, the method for extracting DNA from blood leukocytes involves complicated steps and must be performed soon after blood sampling for sensitive gene analysis. In the present study, we performed eHRG genotyping using DNA, isolated from oral mucosa swabs collected by rubbing the mucosa on the underside of the upper lip of horses and 100 mg of freshly excreted feces obtained by scraping their surface. In the present study, we performed eHRG genotyping using DNA isolated from oral mucosa swabs and feces of horses (18 Thoroughbreds, 17 mixed breeds, 2 warm bloods), and compared the accuracy of this method with that of the method using DNA from leukocytes. The DNA derived from oral mucosa swabs was sufficient in quantity and quality for eHRG genotyping. However, DNA derived from fecal samples requires a more sensitive detection system because of contamination with non-horse DNA, and the test quality is low. Collection of oral mucosa swabs is less invasive than blood sampling; further, oral swabs can be stored for a longer period in a specified high-quality solution. Therefore, collecting DNA samples from oral mucosa swabs is recommended for the genetic analysis of not only horses but also other animals that are not accustomed to humans.

Authentication of important medicinal herbal species through DNA-based molecular characterization

DNA-based molecular markers have great importance among other methods used for the authentication, detection, and identification of medicinal herbal species. Currently, it is more common to identify the medicinal herbal species (monoherbal or polyherbal forms) morphologically by using sensory, macroscopic, and microscopic methods. DNA-based markers made an easy for accurate detection of herbal species by using the polymerase chain reaction (PCR) which involves in vitro amplification of a particular region of DNA sequence. In the current study, we used heterogenic parts for isolation of DNA from twelve important medicinal herbal species followed by purity determination, and yield calculation. We optimized a PCR reaction using universal primer sets to amplify the target DNA followed by DNA sequencing, and species identification. We also performed phylogenetic analysis for determining the evolutionary relationship between the herbal species, by using MEGAX32 software. Further, we prepared adulterated herbal species samples to validate the method. The method was able to amplify the target gene through PCR in 11 out of 12 herbal species samples (sensitivity 91.66%).The DNA from cinnamon could not yield a truly amplified product. On DNA sequencing, all the amplified products were identified as true herbal species (specificity 100%). In the adulterated samples, non-specific DNA bands were observed after performing the PCR reaction, indicating the mixing of more than one herbal species. To conclude, DNA sequencing-based molecular analysis is advantageous for the correct identification, and detection of adulterated herbal species.

The chromosome-level genomes of the herbal magnoliids Warburgia ugandensis and Saururus chinensis

Warburgia ugandensis and Saururus chinensis are two of the most important medicinal plants in magnoliids and are widely utilized in traditional Kenya and Chinese medicine, respectively. The absence of higher-quality reference genomes has hindered research on the medicinal compound biosynthesis mechanisms of these plants. We report the chromosome-level genome assemblies of W. ugandensis and S. chinensis, and generated 1.13 Gb and 0.53 Gb genomes from 74 and 27 scaffolds, respectively, using BGI-DIPSEQ, Nanopore, and Hi-C sequencing. The scaffold N50 lengths were 82.97 Mb and 48.53 Mb, and the assemblies were anchored to 14 and 11 chromosomes of W. ugandensis and S. chinensis, respectively. In total, 24,739 and 20,561 genes were annotated, and 98.5% and 98% of the BUSCO genes were fully represented, respectively. The chromosome-level genomes of W. ugandensis and S. chinensis will be valuable resources for understanding the genetics of these medicinal plants, studying the evolution of magnoliids and angiosperms and conserving plant genetic resources.

Chromosome-level Alstonia scholaris genome unveils evolutionary insights into biosynthesis of monoterpenoid indole alkaloids

Alstonia scholaris of the Apocynaceae family is a medicinal plant with a rich source of bioactive monoterpenoid indole alkaloids (MIAs), which possess anti-cancer activity like vinca alkaloids. To gain genomic insights into MIA biosynthesis, we assembled a high-quality chromosome-level genome for A. scholaris using nanopore and Hi-C data. The 444.95 Mb genome contained 35,488 protein-coding genes. A total of 20 chromosomes were assembled with a scaffold N50 of 21.75 Mb. The genome contained a cluster of strictosidine synthases and tryptophan decarboxylases with synteny to other species and a saccharide-terpene cluster involved in the monoterpenoid biosynthesis pathway of the MIA upstream pathway. The multi-omics data of A. scholaris provide a valuable resource for understanding the evolutionary origins of MIAs and for discovering biosynthetic pathways and synthetic biology efforts for producing pharmaceutically useful alkaloids.

SarCTAB: an efficient and cost-effective DNA isolation protocol from geophytes

Geophytes are herbaceous plants that grow anew from underground buds and are excellent models to study storage organ formation. However, molecular studies involving geophytes are constrained due to the presence of a wide spectrum of polysaccharides and polyphenols that contaminate the genomic DNA. At present, several protocols exist for the extraction of genomic DNA from different plant species; however, isolating high-quality DNA from geophytes is challenging. Such challenges are further complexed by longer incubation time and multiple precipitation steps involved in existing DNA isolation methods. To overcome such problems, we aimed to establish a DNA extraction method (SarCTAB) which is an economical, quick, and sustainable way of DNA isolation from geophytes. We improved the traditional CTAB method by optimizing key ingredients such as sarcosine, β-mercaptoethanol, and high molar concentration of sodium chloride (NaCl), which resulted in high concentration and good-quality DNA with lesser polysaccharides, proteins, and polyphenols. This method was evaluated to extract DNA from storage organs of six different geophytes. The SarCTAB method provides an average yield of 1755 ng/µl of high-quality DNA from 100 mg of underground storage tissues with an average standard purity of 1.86 (260/280) and 1.42 (260/230). The isolated genomic DNA performed well with Inter-simple sequence repeat (ISSR) amplification, restriction digestion with EcoRI, and PCR amplification of plant barcode genes viz. matK and rbcL. Also, the cost involved in DNA isolation was low when compared to that with commercially available kits. Overall, SarCTAB method works effectively to isolate high-quality genomic DNA in a cost-effective manner from the underground storage tissues of geophytes, and can be applied for next-generation sequencing, DNA barcoding, and whole genome bisulfite sequencing.

The complete chloroplast genome of Brassica rapa var. purpuraria (L.H.Bailey) Kitam 1950 and its phylogenetic analysis

Zicaitai (Brassica rapa var. purpuraria (L.H.Bailey) Kitam 1950) is a vegetable crop that boasts a high nutritional value and unique flavor. It originated from Central China and was formed after long-term cultivation and domestication. In this study, we obtained the complete sequence of the chloroplast genome of zicaitai, a circular molecule of 153,483 bp in length. This chloroplast genome consists of a large single-copy (LSC) region (83,282 bp), a small single-copy (SSC) region (17,775 bp), and a pair of inverted repeats (IRs) (26,213 bp). By sequence annotation, 132 genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes were identified in the zicaitai chloroplast. A total of 315 simple sequence repeats (SSRs) were found located in LSC (197), SSC (72), and IR (46), respectively. Phylogenetic analysis based on chloroplast genomes indicated the relationship of zicaitai and the Brassicaceae family, which supports zicaitai as a variety of B. rapa in taxonomy. The results obtained in this study provide insight into further research on Brassica chloroplasts and their phylogeny.

Cationic and anionic detergent buffers in sequence yield high-quality genomic DNA from diverse plant species

Because of the heterogeneity among seedlings of outbreeding species, the use of seedling tissues as a source of DNA is unsuitable for the genomic characterization of elite germplasms. High-quality DNA, free of RNA, proteins, polysaccharides, secondary metabolites, and shearing, is mandatory for downstream molecular biology applications, especially for next-generation genome sequencing and pangenome analysis aiming to capture the complete genetic diversity within a species. The study aimed to accomplish an efficient protocol for the extraction of high-quality DNA suitable for diverse plant species/tissues. We describe a reliable, and consistent protocol suitable for the extraction of DNA from 42 difficult-to-extract plant species belonging to 33 angiosperm (monocot and dicot) families, including tissues such as seeds, roots, endosperm, and flower/fruit tissues. The protocol was first optimized for the outbreeding recalcitrant trees viz., Prosopis cineraria, Conocarpus erectus, and Phoenix dactylifera, which are rich in proteins, polysaccharides, and secondary metabolites, and the quality of the extracted DNA was confirmed by downstream applications. Nine procedures were attempted to extract high-quality, impurities-free DNA from these three plant species. Extraction of the ethanol-precipitated DNA from cetyltrimethylammonium bromide (CTAB) protocol using sodium dodecyl sulfate (SDS) buffer, i.e., the extraction using a cationic (CTAB) detergent followed by an anionic (SDS) detergent was the key for high yield and high purity (1.75-1.85 against A260/280 and an A260/230 ratio of >2) DNA. A vice versa extraction procedure, i.e., SDS buffer followed by CTAB buffer, and also CTAB buffer followed by CTAB, did not yield good-quality DNA. PCR (using different primers) and restriction endonuclease digestion of the DNA extracted from these three plants validated the protocol. The accomplishment of the genome of P. cineraria using the DNA extracted using the modified protocol confirmed its applicability to genomic studies. The optimized protocol successful in extracting high-quality DNA from diverse plant species/tissues extends its applicability and is useful for accomplishing genome sequences of elite germplasm of recalcitrant plant species with quality reads.

Isolation of High-Molecular-Weight DNA for Long-Read Sequencing Using a High-Salt Gel Electroelution Trap

Long-read sequencing technologies require high-molecular-weight (HMW) DNA of sufficient purity and integrity, which can be difficult to obtain from complex biological samples. We propose a method for purifying HMW DNA that takes advantage of the fact that DNA's electrophoretic mobility decreases in a high-ionic-strength environment. The method begins with the separation of HMW DNA from various impurities by electrophoresis in an agarose gel-filled channel. After sufficient separation, a high-salt gel block is placed ahead of the DNA band of interest, leaving a gap between the separating gel and the high-salt gel that serves as a reservoir for sample collection. The DNA is then electroeluted from the separating gel into the reservoir, where its migration slows due to electrostatic shielding of the DNA's negative charge by excess counterions from the high-salt gel. As a result, the reservoir accumulates HMW DNA of high purity and integrity, which can be easily collected and used for long-read sequencing and other demanding applications without additional desalting. The method is simple and inexpensive, yields sequencing-grade HMW DNA even from difficult plant and soil samples, and has the potential for automation and scalability.

Chromosome-scale genomes of commercial timber trees (Ochroma pyramidale, Mesua ferrea, and Tectona grandis)

Wood is the most important natural and endlessly renewable source of energy. Despite the ecological and economic importance of wood, many aspects of its formation have not yet been investigated. We performed chromosome-scale genome assemblies of three timber trees (Ochroma pyramidale, Mesua ferrea, and Tectona grandis) which exhibit different wood properties such as wood density, hardness, growth rate, and fiber cell wall thickness. The combination of 10X, stLFR, Hi-Fi sequencing and HiC data led us to assemble high-quality genomes evident by scaffold N50 length of 55.97 Mb (O. pyramidale), 22.37 Mb (M. ferrea) and 14.55 Mb (T. grandis) with >97% BUSCO completeness of the assemblies. A total of 35774, 24027, and 44813 protein-coding genes were identified in M. ferrea, T. grandis and O. pyramidale, respectively. The data generated in this study is anticipated to serve as a valuable genetic resource and will promote comparative genomic analyses, and it is of practical importance in gaining a further understanding of the wood properties in non-model woody species.

Chromosome-level genome assembly and population genomics of Robinia pseudoacacia reveal the genetic basis for its wide cultivation

Urban greening provides important ecosystem services and ideal places for urban recreation and is a serious consideration for municipal decision-makers. Among the tree species cultivated in urban green spaces, Robinia pseudoacacia stands out due to its attractive flowers, fragrances, high trunks, wide adaptability, and essential ecosystem services. However, the genomic basis and consequences of its wide-planting in urban green spaces remains unknown. Here, we report the chromosome-level genome assembly of R. pseudoacacia, revealing a genome size of 682.4 Mb and 33,187 protein-coding genes. More than 99.3% of the assembly is anchored to 11 chromosomes with an N50 of 59.9 Mb. Comparative genomic analyses among 17 species reveal that gene families related to traits favoured by urbanites, such as wood formation, biosynthesis, and drought tolerance, are notably expanded in R. pseudoacacia. Our population genomic analyses further recover 11 genes that are under recent selection. Ultimately, these genes play important roles in the biological processes related to flower development, water retention, and immunization. Altogether, our results reveal the evolutionary forces that shape R. pseudoacacia cultivated for urban greening. These findings also present a valuable foundation for the future development of agronomic traits and molecular breeding strategies for R. pseudoacacia.

Balancing read length and sequencing depth: Optimizing Nanopore long-read sequencing for monocots with an emphasis on the Liliales

Premise

We present approaches used to generate long-read Nanopore sequencing reads for the Liliales and demonstrate how modifications to standard protocols directly impact read length and total output. The goal is to help those interested in generating long-read sequencing data determine which steps may be necessary for optimizing output and results.

Methods

Four species of Calochortus (Liliaceae) were sequenced. Modifications made to sodium dodecyl sulfate (SDS) extractions and cleanup protocols included grinding with a mortar and pestle, using cut or wide-bore tips, chloroform cleaning, bead cleaning, eliminating short fragments, and using highly purified DNA.

Results

Steps taken to maximize read length can decrease overall output. Notably, the number of pores in a flow cell is correlated with the overall output, yet we did not see an association between the pore number and the read length or the number of reads produced.

Discussion

Many factors contribute to the overall success of a Nanopore sequencing run. We showed the direct impact that several modifications to the DNA extraction and cleaning steps have on the total sequencing output, read size, and number of reads generated. We show a tradeoff between read length and the number of reads and, to a lesser extent, the total sequencing output, all of which are important factors for successful de novo genome assembly.

Testing protocols to optimize DNA extraction from tough leaf tissue: A case study in Encephalartos

Premise

Plants with stiff, leathery leaves pose a challenge for standard DNA extraction protocols. These tissues are recalcitrant to mechanical disruption via TissueLyser (or analogous devices) and are often high in secondary metabolites. These compounding factors result in low yields, which may be sufficient for PCR amplification but are generally inadequate for genomic applications that require large quantities of high-quality DNA. Cycads in the genus Encephalartos exemplify these challenges, as this group of plants is fortified for life in harsh, dry habitats with notoriously thick and rigid leaves.

Methods and Results

Using a DNA extraction kit, we tested three methods of mechanical disruption and examined the differences between stored vs. freshly collected samples and mature vs. senescing leaflets. We found that the manual method of pulverizing tissue yields the highest concentrations of DNA, and that both senescing leaflets and leaflet tissue that has been stored for extended periods yield sufficient DNA for genomic analyses.

Conclusions

These findings shed light on the feasibility of using senescing leaves and/or tissue that has been stored on silica for long periods of time when attempting to extract large amounts of DNA. We provide here an optimized DNA extraction protocol that can be applied to cycads and other plant groups with tough or rigid leaves.

Comparative Analysis of Chloroplast Genome of Desmodium stryacifolium with Closely Related Legume Genome from the Phaseoloid Clade

Desmodium styracifolium is a medicinal plant from the Desmodieae tribe, also known as Grona styracifolia. Its role in the treatment of urolithiasis, urinary infections, and cholelithiasis has previously been widely documented. The complete chloroplast genome sequence of D. Styracifolium is 149,155 bp in length with a GC content of 35.2%. It is composed of a large single copy (LSC) of 82,476 bp and a small single copy (SSC) of 18,439 bp, which are separated by a pair of inverted repeats (IR) of 24,120 bp each and has 128 genes. We performed a comparative analysis of the D. styracifolium cpDNA with the genome of previously investigated members of the Sesamoidea tribe and on the outgroup from its Phaseolinae sister tribe. The size of all seven cpDNAs ranged from 148,814 bp to 151,217 bp in length due to the contraction and expansion of the IR/SC boundaries. The gene orientation of the SSC region in D. styracifolium was inverted in comparison with the other six studied species. Furthermore, the sequence divergence of the IR regions was significantly lower than that of the LSC and the SSC, and five highly divergent regions, trnL-UAA-trnT-UGU, psaJ-ycf4, psbE-petL, rpl36-rps8, and rpl32-trnL-UGA, were identified that could be used as valuable molecular markers in future taxonomic studies and phylogenetic constructions.

The complete chloroplast genome of Primula calliantha subsp. bryophila, an ornamental alpine plant from China

Primula calliantha subsp. bryophila (Balf. f. et Farrer) W.W. Smith and Forrest (1928) is a perennial alpine species with ornamental value. It is distributed in northwestern Yunnan and adjacent eastern Tibet of China, and northern Myanmar. Here, we sequenced and assembled complete plastid genome of P. calliantha subsp. bryophila, which is a circular molecule of 152,045 bp in length, including a large single-copy region (83,966 bp), a small single-copy region (17,663 bp), and a pair of inverted repeats (25,208 bp). The chloroplast genome contained 113 genes, including 79 protein-coding genes, four rRNA genes, and 30 tRNA genes. The phylogenetic tree based on chloroplast genomes showed the relative relationship of P. calliantha subsp. bryophila and P. calliantha, which further supports P. calliantha subsp. bryophila as a subspecies of P. calliantha in taxonomy. The complete chloroplast (cp) genome of P. calliantha subsp. bryophila provides valuable data for further phylogenetic studies of Primulaceae.

MicroRNA Identification, Target Prediction, and Validation for Crop Improvement

Micro-RNAs (mi-RNAs) are regulatory elements that play a vital role in the growth, development, and metabolic regulation of plants. In current research, the isolation of miRNAs is a tedious and difficult task using in vitro methods. However, recent exploration into the remarkably highly conserved nature of nucleotide sequences of miRNAs assists in the identification of miRNAs in plant species through homologous approaches. Here, we describe the in silico-based method for identification of miRNAs from the EST database which is emerging as a faster and more reliable approach along with the development of miRNA-SSR markers. This approach has the potential to accelerate research into the regulation of gene expression in various plant species such as tea, potato, tomato, tobacco, and orphan crops like cluster bean.

A draft genome of the medicinal plant Cremastra appendiculata (D. Don) provides insights into the colchicine biosynthetic pathway

Cremastra appendiculata (D. Don) Makino is a rare terrestrial orchid with a high market value as an ornamental and Chinese traditional medicinal herb with a wide range of pharmacological properties. The pseudobulbs of C. appendiculata are one of the primary sources of the famous traditional Chinese medicine "Shancigu", which has been clinically used for treating many diseases, especially, as the main component to treat gout. The lack of genetic research and genome data restricts the modern development and clinical use of C. appendiculata. Here, we report a 2.3 Gb chromosome-level genome of C. appendiculata. We identify a series of candidates of 35 candidate genes responsible for colchicine biosynthesis, among which O-methyltransferase (OMT) gene exhibits an important role in colchicine biosynthesis. Co-expression analysis reveal purple and green-yellow module have close relationships with pseudobulb parts and comprise most of the colchicine pathway genes. Overall, our genome data and the candidate genes reported here set the foundation to decipher the colchicine biosynthesis pathways in medicinal plants.

Application of MaxEnt Modeling and HRM Analysis to Support the Conservation and Domestication of Gevuina avellana Mol. in Central Chile

The Chilean hazelnut (Gevuina avellana Mol., Proteaceae) is a native tree of Chile and Argentina of edible fruit-type nut. We applied two approaches to contribute to the development of strategies for mitigation of the effects of climate change and anthropic activities in G. avellana. It corresponds to the first report where both tools are integrated, the MaxEnt model to predict the current and future potential distribution coupled with High-Resolution Melting Analysis (HRM) to assess its genetic diversity and understand how the species would respond to these changes. Two global climate models: CNRM-CM6-1 and MIROC-ES2L for four Shared Socioeconomic Pathways: 126, 245, 370, and 585 (2021−2040; 2061−2080) were evaluated. The annual mean temperature (43.7%) and water steam (23.4%) were the key factors for the distribution current of G. avellana (AUC = 0.953). The future prediction model shows to the year 2040 those habitat range decreases at 50% (AUC = 0.918). The genetic structure was investigated in seven natural populations using eight EST-SSR markers, showing a percentage of polymorphic loci between 18.69 and 55.14% and low genetic differentiation between populations (Fst = 0.052; p < 0.001). According to the discriminant analysis of principal components (DAPC) we identified 10 genetic populations. We conclude that high-priority areas for protection correspond to Los Avellanos and Punta de Águila populations due to their greater genetic diversity and allelic richness.

Comparison of DNA purification methods for high-throughput sequencing of fungal communities from wine fermentation

High-throughput sequencing approaches, which target a taxonomically discriminant locus, allow for in-depth insight into microbial communities' compositions. Although microorganisms are historically investigated by cultivation on artificial culture media, this method presents strong limitations, since only a limited proportion of microorganisms can be grown in vitro. This pitfall appears even more limiting in enological and winemaking processes, during which a wide range of molds, yeasts, and bacteria are observed at the different stages of the fermentation course. Such an understanding of those dynamic communities and how they impact wine quality therefore stands as a major challenge for the future of enology. As of now, although high-throughput sequencing has already allowed for the investigation of fungal communities, there is no available comparative study focusing on the performance of microbial deoxyribonucleic acid (DNA) extraction in enological matrixes. This study aims to provide a comparison of five selected extraction methods, assayed on both must and fermenting must, as well as on finished wine. These procedures were evaluated according to their extraction yields, the purity of their extracted DNA, and the robustness of downstream molecular analyses, including polymerase chain reaction and high-throughput sequencing of fungal communities. Altogether, two out of the five assessed microbial DNA extraction methods (DNeasy PowerSoil Pro Kit and E.Z.N.A.® Food DNA Kit) appeared suitable for robust evaluations of the microbial communities in wine samples. Consequently, this study provides robust tools for facilitated upcoming studies to further investigate microbial communities during winemaking using high-throughput sequencing.

Chromosome-level genome of Pedinomonas minor (Chlorophyta) unveils adaptations to abiotic stress in a rapidly fluctuating environment

The Pedinophyceae (Viridiplantae) comprise a class of small uniflagellate algae with a pivotal position in the phylogeny of the Chlorophyta as the sister group of the 'core chlorophytes'. We present a chromosome-level genome assembly of the freshwater type species of the class, Pedinomonas minor. We sequenced the genome using Pacbio, Illumina and Hi-C technologies, performed comparative analyses of genome and gene family evolution, and analyzed the transcriptome under various abiotic stresses. Although the genome is relatively small (55 Mb), it shares many traits with core chlorophytes including number of introns and protein-coding genes, messenger RNA (mRNA) lengths, and abundance of transposable elements. Pedinomonas minor is only bounded by the plasma membrane, thriving in temporary habitats that frequently dry out. Gene family innovations and expansions and transcriptomic responses to abiotic stresses have shed light on adaptations of P. minor to its fluctuating environment. Horizontal gene transfers from bacteria and fungi have possibly contributed to the evolution of some of these traits. We identified a putative endogenization site of a nucleocytoplasmic large DNA virus and hypothesized that endogenous viral elements donated foreign genes to the host genome, their spread enhanced by transposable elements, located at gene boundaries in several of the expanded gene families.

The Cycas genome and the early evolution of seed plants

Cycads represent one of the most ancient lineages of living seed plants. Identifying genomic features uniquely shared by cycads and other extant seed plants, but not non-seed-producing plants, may shed light on the origin of key innovations, as well as the early diversification of seed plants. Here, we report the 10.5-Gb reference genome of Cycas panzhihuaensis, complemented by the transcriptomes of 339 cycad species. Nuclear and plastid phylogenomic analyses strongly suggest that cycads and Ginkgo form a clade sister to all other living gymnosperms, in contrast to mitochondrial data, which place cycads alone in this position. We found evidence for an ancient whole-genome duplication in the common ancestor of extant gymnosperms. The Cycas genome contains four homologues of the fitD gene family that were likely acquired via horizontal gene transfer from fungi, and these genes confer herbivore resistance in cycads. The male-specific region of the Y chromosome of C. panzhihuaensis contains a MADS-box transcription factor expressed exclusively in male cones that is similar to a system reported in Ginkgo, suggesting that a sex determination mechanism controlled by MADS-box genes may have originated in the common ancestor of cycads and Ginkgo. The C. panzhihuaensis genome provides an important new resource of broad utility for biologists.

A high-quality assembled genome and its comparative analysis decode the adaptive molecular mechanism of the number one Chinese cotton variety CRI-12

BACKGROUND

Gossypium hirsutum L. is the most widely cultivated cotton species, and a high-quality reference genome would be a huge boost for researching the molecular mechanism of agronomic traits in cotton.

FINDINGS

Here, Pacific Biosciences and Hi-C sequencing technologies were used to assemble a new upland cotton genome of the No. 1 Chinese cotton variety CRI-12. We generated a high-quality assembled CRI-12 genome of 2.31 Gb with a contig N50 of 19.65 Mb, which was superior to previously reported genomes. Comparisons between CRI-12 and other reported genomes revealed 7,966 structural variations and 7,378 presence/absence variations. The distribution of the haplotypes among A-genome (Gossypium arboreum), D-genome (Gossypium raimondii), and AD-genome (G. hirsutum and Gossypium barbadense) suggested that many haplotypes were lost and recombined in the process of polyploidization. More than half of the haplotypes that correlated with different tolerances were located on chromosome D13, suggesting that this chromosome may be important for wide adaptation. Finally, it was demonstrated that DNA methylation may provide advantages in environmental adaptation through whole-genome bisulfite sequencing analysis.

CONCLUSIONS

This research provides a new reference genome for molecular biology research on Gossypium hirsutum L. and helps decode the broad environmental adaptation mechanisms in the No. 1 Chinese cotton variety CRI-12.

The genome of hibiscus hamabo reveals its adaptation to saline and waterlogged habitat

Hibiscus hamabo is a semi-mangrove species with strong tolerance to salt and waterlogging stress. However, the molecular basis and mechanisms that underlie this strong adaptability to harsh environments remain poorly understood. Here, we assembled a high-quality, chromosome-level genome of this semi-mangrove plant and analyzed its transcriptome under different stress treatments to reveal regulatory responses and mechanisms. Our analyses suggested that H. hamabo has undergone two recent successive polyploidy events, a whole-genome duplication followed by a whole-genome triplication, resulting in an unusually large gene number (107 309 genes). Comparison of the H. hamabo genome with that of its close relative Hibiscus cannabinus, which has not experienced a recent WGT, indicated that genes associated with high stress resistance have been preferentially preserved in the H. hamabo genome, suggesting an underlying association between polyploidy and stronger stress resistance. Transcriptomic data indicated that genes in the roots and leaves responded differently to stress. In roots, genes that regulate ion channels involved in biosynthetic and metabolic processes responded quickly to adjust the ion concentration and provide metabolic products to protect root cells, whereas no such rapid response was observed from genes in leaves. Using co-expression networks, potential stress resistance genes were identified for use in future functional investigations. The genome sequence, along with several transcriptome datasets, provide insights into genome evolution and the mechanism of salt and waterlogging tolerance in H. hamabo, suggesting the importance of polyploidization for environmental adaptation.

The complete chloroplast genome of Desmodium styracifolium

The complete chloroplast genome (cpDNA) of Desmodium styracifolium, an important medicinal herb for urolithiasis treatment, was sequenced and assembled from the whole genome data. The cpDNA of D. styracifolium is 149,155 bp in length with GC content of 35.2%. The genome has a quadripartite structure that is composed of a large single-copy (LCS, 82,476 bp) and small single-copy (SSC, 18,439 bp) separated by a pair of inverted repeats (IRa and IRb, 24,120 bp each). There are 128 genes in the chloroplast genome, including 83 protein-coding genes, 8 rRNA genes and 37 tRNA genes.

The chromosome-scale genomes of Dipterocarpus turbinatus and Hopea hainanensis (Dipterocarpaceae) provide insights into fragrant oleoresin biosynthesis and hardwood formation

Dipterocarpaceae are typical tropical plants (dipterocarp forests) that are famous for their high economic value because of their production of fragrant oleoresins, top-quality timber and usage in traditional Chinese medicine. Currently, the lack of Dipterocarpaceae genomes has been a limiting factor to decipher the fragrant oleoresin biosynthesis and gain evolutionary insights into high-quality wood formation in Dipterocarpaceae. We generated chromosome-level genome assemblies for two representative Dipterocarpaceae species viz. Dipterocarpus turbinatus Gaertn. f. and Hopea hainanensis Merr. et Chun. Our whole-genome duplication (WGD) analysis revealed that Dipterocarpaceae underwent a shared WGD event, which showed significant impacts on increased copy numbers of genes related to the biosynthesis of terpene, BAHD acyltransferases, fatty acid and benzenoid/phenylpropanoid, which probably confer to the formation of their characteristic fragrant oleoresin. Additionally, compared with common soft wood plants, the expansion of gene families was also found to be associated with wood formation, such as in CESA (cellulose synthase), CSLE (cellulose synthase-like protein E), laccase and peroxidase in Dipterocarpaceae genomes, which might also contribute to the formation of harder, stronger and high-density timbers. Finally, an integrative analysis on a combination of genomic, transcriptomic and metabolic data from different tissues provided further insights into the molecular basis of fragrant oleoresins biosynthesis and high-quality wood formation of Dipterocarpaceae. Our study contributes the first two representative genomes for Dipterocarpaceae, which are valuable genetic resources for further researches on the fragrant oleoresins and superior-quality timber, genome-assisted breeding and improvement, and conservation biology of this family.

Mangrove diversity is more than fringe deep

Mangroves form coastal tropical forests in the intertidal zone and are an important component of shoreline protection. In comparison to other tropical forests, mangrove stands are thought to have relatively low genetic diversity with population genetic structure gradually increasing with distance along a coastline. We conducted genetic analyses of mangrove forests across a range of spatial scales; within a 400 m² parcel comprising 181 Rhizophora mangle (red mangrove) trees, and across four sites ranging from 6-115 km apart in Honduras. In total, we successfully genotyped 269 R. mangle trees, using a panel of 677 SNPs developed with 2b-RAD methodology. Within the 400 m² parcel, we found two distinct clusters with high levels of genetic differentiation (F_ST = 0.355), corresponding to trees primarily located on the seaward fringe and trees growing deeper into the forest. In contrast, there was limited genetic differentiation (F_ST = 0.027-0.105) across the sites at a larger scale, which had been predominantly sampled along the seaward fringe. Within the 400 m² parcel, the cluster closest to the seaward fringe exhibited low genetic differentiation (F_ST = 0.014-0.043) with the other Honduran sites, but the cluster further into the forest was highly differentiated from them (F_ST = 0.326-0.414). These findings contradict the perception that genetic structure within mangroves forests occurs mainly along a coastline and highlights that there is greater genetic structure at fine spatial scales.

Basic chloroplast genome characterization of Phalaenopsis stobartiana (Orchidaceae) from China

Phalaenopsis stobartiana Reichenbach f. 1877 is mainly distributed in Yunnan province of China and has a high ornamental and breeding value. Here, we reported the chloroplast genome of P. stobartiana. The length of the chloroplast genome was 145,900 bp, encoding 120 genes. The average GC content was 36.8%. Phylogenetic analysis revealed that P. stobartiana and P. wilsonii are closely related. The chloroplast genome could be used for further phylogenetic research, and provide molecular data for future genetic protection and breeding programs.

Chloranthus genome provides insights into the early diversification of angiosperms

Chloranthales remain the last major mesangiosperm lineage without a nuclear genome assembly. We therefore assemble a high-quality chromosome-level genome of Chloranthus spicatus to resolve enigmatic evolutionary relationships, as well as explore patterns of genome evolution among the major lineages of mesangiosperms (eudicots, monocots, magnoliids, Chloranthales, and Ceratophyllales). We find that synteny is highly conserved between genomic regions of Amborella, Vitis, and Chloranthus. We identify an ancient single whole-genome duplication (WGD) (κ) prior to the divergence of extant Chloranthales. Phylogenetic inference shows Chloranthales as sister to magnoliids. Furthermore, our analyses indicate that ancient hybridization may account for the incongruent phylogenetic placement of Chloranthales + magnoliids relative to monocots and eudicots in nuclear and chloroplast trees. Long genes and long introns are found to be prevalent in both Chloranthales and magnoliids compared to other angiosperms. Overall, our findings provide an improved context for understanding mesangiosperm relationships and evolution and contribute a valuable genomic resource for future investigations.

Endophytic bacterial communities are associated with leaf mimicry in the vine Boquila trifoliolata

The mechanisms behind the unique capacity of the vine Boquila trifoliolata to mimic the leaves of several tree species remain unknown. A hypothesis in the original leaf mimicry report considered that microbial vectors from trees could carry genes or epigenetic factors that would alter the expression of leaf traits in Boquila. Here we evaluated whether leaf endophytic bacterial communities are associated with the mimicry pattern. Using 16S rRNA gene sequencing, we compared the endophytic bacterial communities in three groups of leaves collected in a temperate rainforest: (1) leaves from the model tree Rhaphithamnus spinosus (RS), (2) Boquila leaves mimicking the tree leaves (BR), and (3) Boquila leaves from the same individual vine but not mimicking the tree leaves (BT). We hypothesized that bacterial communities would be more similar in the BR-RS comparison than in the BT-RS comparison. We found significant differences in the endophytic bacterial communities among the three groups, verifying the hypothesis. Whereas non-mimetic Boquila leaves and tree leaves (BT-RS) showed clearly different bacterial communities, mimetic Boquila leaves and tree leaves (BR-RS) showed an overlap concerning their bacterial communities. The role of bacteria in this unique case of leaf mimicry should be studied further.

EXTRACTION AND PURITY DNA OF Culex spp MOSQUITO IN KEMELAK VILLAGE, BINDUNG LANGIT, OGAN KOMERING ULU

Culex spp are mosquito vectors that have a very wide distribution capability and are carriers of pathogens that can interfere with human and animal health. The wide distribution makes Culex spp a dangerous threat. DNA extraction is one of the important steps in obtaining genetic information and genetic analysis. Good quality DNA is used for activities such as the use of molecular markers, genome library creation, and sequencing. This study aims to determine the quality, concentration and purity of Culex spp mosquito DNA in Kemelak Bindung Langit Village, OKU Regency. It is hoped that the sample can be used for further research analysis on Mitochondria D-Loop Sequences in Culex spp mosquitoes. Quantitative measurement of DNA in the form of concentration and purity of DNA using Nanodrop Thermo cycle while qualitative DNA using electrophoresis technique. The results of the isolation of the mosquito genome DNA, obtained clear DNA bands without any degradation (smear) and the concentration results for the four samples ranged from 10-100 ng/µL and the DNA purity was good, ranging from 1.8 to 2.00.

The Clausena lansium (Wampee) genome reveal new insights into the carbazole alkaloids biosynthesis pathway

Clausena lansium (Lour.) Skeels (Rutaceae), recognized as wampee, is a widely distributed fruit tree which is utilized as a folk-medicine for treatment of several common diseases. However, the genomic information about this medicinally important species is still lacking. Therefore, we assembled the first genome of Clausena genus with a total length of 310.51 Mb and scaffold N50 of 2.24 Mb by using 10× Genomics technology. Further annotation revealed a total of 34,419 protein-coding genes, while repetitive elements covered 39.08% (121.36 Mb) of the genome. The Clausena and Citrus genus were found to diverge around 22 MYA, and also shared an ancient whole-genome triplication event with Vitis. Furthermore, multi-tissue transcriptomic analysis enabled the identification of genes involved in the synthesis of carbazole alkaloids. Altogether, these findings provided new insights into the genome evolution of Wampee species and highlighted the possible role of key genes involved in the carbazole alkaloids biosynthetic pathway.

Green Synthesis of Fluorescent Carbon Dots from Elaeagnus angustifolia and its Application as Tartrazine Sensor

This article has introduced and examined a novel and green approach for the very first time, which had been developed for the synthesis of carbon dots (CDs) and performed through the utilization of Elaeagnus angustifolia (E. A) as a natural carbon source. This straightforward procedure has been based upon a hydrothermal treatment with a quantum yield of 16.8% that had been designed to synthesize water-soluble CDs in one step and result in a satisfying fluorescence. Additionally, we have attempted to assess the sensing system that had been exerted through the usage of CDs for the detection of food colorant tartrazine, since they can function as a fluorescent sensor due to the interplay that occurs among tartrazine and CDs leading to the quenching of their fluorescence. The detection limit has been measured to be equaled to 0.086 μM (86 nM) and the linear range has been observed to be 0.47-234 μM. The proposed highly sensitive and simple method has exhibited an excellent selectivity and proved to be effectively applicable for distinguishing the tartrazine of real samples.

The Draft Genome of Coelastrum proboscideum (Sphaeropleales, Chlorophyta)

Coelastrum proboscideum Bohlin, 1896 (Sphaeropleales, Scenedesmaceae, Chlorophyta) is a coenobial species with cosmopolitan distribution in diverse freshwater habitats. Coelastrum spp. are widely tested for biotechnological applications such as carotenoid and lipid production, and in bioremediation of wastewater. Here, we report the draft genome of C. proboscideum var. dilatatum strain SAG 217-2. The final assembly comprised 125,935,854 bp with over 8357 scaffolds. The whole-genome data is publicly available in the Nucleotide Sequence Archive (CNSA) of China National GeneBank (CNGB) (https://db.cngb.org/cnsa/) under the accession number CNA0014153.

Mitochondrial genome of Salix cardiophylla and its implications for infrageneric division of the genus of Salix

Salix cardiophylla was a member of the genus of Salix in family Salicaceae with unique morphological traits, and once recognized as a separate genus, Toisusu Kimura. Here, we sequenced and assembled the complete mitochondrial genome of S. cardiophylla, which was 735,173 bp in length, including 56 genes, 28 protein-coding genes, 3 rRNA genes, 25 tRNA genes, and one large inverted repeat regions with length of 13,603 bp. Phylogenetic analysis based on 26 mitochondrial CDS confirmed that S. cardiophylla is a member of Salix, and support its merge into Salix in aspect of our new insights on mitogenome phylogenomics.

The genome of Prasinoderma coloniale unveils the existence of a third phylum within green plants

Genome analysis of the pico-eukaryotic marine green alga Prasinoderma coloniale CCMP 1413 unveils the existence of a novel phylum within green plants (Viridiplantae), the Prasinodermophyta, which diverged before the split of Chlorophyta and Streptophyta. Structural features of the genome and gene family comparisons revealed an intermediate position of the P. coloniale genome (25.3 Mb) between the extremely compact, small genomes of picoplanktonic Mamiellophyceae (Chlorophyta) and the larger, more complex genomes of early-diverging streptophyte algae. Reconstruction of the minimal core genome of Viridiplantae allowed identification of an ancestral toolkit of transcription factors and flagellar proteins. Adaptations of P. coloniale to its deep-water, oligotrophic environment involved expansion of light-harvesting proteins, reduction of early light-induced proteins, evolution of a distinct type of C4 photosynthesis and carbon-concentrating mechanism, synthesis of the metal-complexing metabolite picolinic acid, and vitamin B1, B7 and B12 auxotrophy. The P. coloniale genome provides first insights into the dawn of green plant evolution.

The draft genome assembly of the critically endangered Nyssa yunnanensis, a plant species with extremely small populations endemic to Yunnan Province, China

Nyssa yunnanensis is a deciduous tree species in the family Nyssaceae within the order Cornales. As only eight individual trees and two populations have been recorded in China's Yunnan province, this species has been listed among China's national Class I protection species since 1999 and also among 120 PSESP (Plant Species with Extremely Small Populations) in the Implementation Plan of Rescuing and Conserving China's Plant Species with Extremely Small Populations (PSESP) (2011-2-15). Here, we present the draft genome assembly of N. yunnanensis. Using 10X Genomics linked-reads sequencing data, we carried out the de novo assembly and annotation analysis. The N. yunnanensis genome assembly is 1475 Mb in length, containing 288,519 scaffolds with a scaffold N50 length of 985.59 kb. Within the assembled genome, 799.51 Mb was identified as repetitive elements, accounting for 54.24% of the sequenced genome, and a total of 39,803 protein-coding genes were predicted. With the genomic characteristics of N. yunnanensis available, our study might facilitate future conservation biology studies to help protect this extremely threatened tree species.

Identification of the amino acid position controlling the different enzymatic activities in walnut tyrosinase isoenzymes (jrPPO1 and jrPPO2)

Polyphenol oxidases (PPOs) are ubiquitously distributed among plants, bacteria, fungi and animals. They catalyze the hydroxylation of monophenols (monophenolase activity) and the oxidation of o-diphenols (diphenolase activity) to o-quinones. PPOs are commonly present as an isoenzyme family. In walnut (Juglans regia), two different genes (jrPPO1 and jrPPO2) encoding PPOs have been identified. In this study, jrPPO2 was, for the first time, heterologously expressed in E. coli and characterized as a tyrosinase (TYR) by substrate scope assays and kinetic investigations, as it accepted tyramine and L-tyrosine as substrates. Moreover, the substrate acceptance and kinetic parameters (k_cat and K_m values) towards 16 substrates naturally present in walnut were assessed for jrPPO2 (TYR) and its isoenzyme jrPPO1 (TYR). The two isoenzymes prefer different substrates, as jrPPO1 shows a higher activity towards monophenols, whereas jrPPO2 is more active towards o-diphenols. Molecular docking studies performed herein revealed that the amino acid residue in the position of the 1st activity controller (His_B1 + 1; in jrPPO1 Asn240 and jrPPO2 Gly240) is responsible for the different enzymatic activities. Additionally, interchanging the 1st activity controller residue of the two enzymes in two mutants (jrPPO1-Asn240Gly and jrPPO2-Gly240Asn) proved that the amino acid residue located in this position allows plants to selectively target or dismiss substrates naturally present in walnut.

Dissecting the genome of star fruit (Averrhoa carambola L.)

Averrhoa carambola is commonly known as star fruit because of its peculiar shape, and its fruit is a rich source of minerals and vitamins. It is also used in traditional medicines in countries such as India, China, the Philippines, and Brazil for treating various ailments, including fever, diarrhea, vomiting, and skin disease. Here, we present the first draft genome of the Oxalidaceae family, with an assembled genome size of 470.51 Mb. In total, 24,726 protein-coding genes were identified, and 16,490 genes were annotated using various well-known databases. The phylogenomic analysis confirmed the evolutionary position of the Oxalidaceae family. Based on the gene functional annotations, we also identified enzymes that may be involved in important nutritional pathways in the star fruit genome. Overall, the data from this first sequenced genome in the Oxalidaceae family provide an essential resource for nutritional, medicinal, and cultivational studies of the economically important star-fruit plant.

Purple haze: Cryptic purple sequestrate Cortinarius in New Zealand

CORTINARIUS

is a species-rich ectomycorrhizal genus containing taxa that exhibit agaricoid or sequestrate basidiome morphologies. In New Zealand, one of the most recognizable and common Cortinarius species is the purple sequestrate fungus, C. porphyroideus. We used genome skimming of the almost 100-y-old type specimen from C. porphyroideus to obtain the nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) and partial nuc rDNA 28S (28S) sequences. The phylogenetic position of C. porphyroideus was established, and we found that it represents a rarely collected species. Purple sequestrate Cortinarius comprise multiple cryptic species in several lineages. We describe four new species of Cortinarius with strong morphological similarity to C. porphyroideus: Cortinarius diaphorus, C. minorisporus, C. purpureocapitatus, and C. violaceocystidiatus. Based on molecular evidence, Thaxterogaster viola is recognized as Cortinarius violaceovolvatus var. viola. These species are associated with Nothofagus (southern beech) and have very similar morphology to C. porphyroideus but are all phylogenetically distinct based on molecular data.

Strategies for reducing per-sample costs in target capture sequencing for phylogenomics and population genomics in plants

The reduced cost of high-throughput sequencing and the development of gene sets with wide phylogenetic applicability has led to the rise of sequence capture methods as a plausible platform for both phylogenomics and population genomics in plants. An important consideration in large targeted sequencing projects is the per-sample cost, which can be inflated when using off-the-shelf kits or reagents not purchased in bulk. Here, we discuss methods to reduce per-sample costs in high-throughput targeted sequencing projects. We review the minimal equipment and consumable requirements for targeted sequencing while comparing several alternatives to reduce bulk costs in DNA extraction, library preparation, target enrichment, and sequencing. We consider how each of the workflow alterations may be affected by DNA quality (e.g., fresh vs. herbarium tissue), genome size, and the phylogenetic scale of the project. We provide a cost calculator for researchers considering targeted sequencing to use when designing projects, and identify challenges for future development of low-cost sequencing in non-model plant systems.

Identification of trombiculid mites (Acari: Trombiculidae) on rodents from Chiloé Island and molecular evidence of infection with Orientia species

Background

Scrub typhus is an emerging vector-borne zoonosis, caused by Orientia spp. and transmitted by larvae of trombiculid mites, called chiggers. It mainly occurs within a region of the Asia-Pacific called the tsutsugamushi triangle, where rodents are known as the most relevant hosts for the trombiculid vector. However, the reservoir(s) and vector(s) of the scrub typhus outside Asia-Pacific are unknown. The disease has recently been discovered on and is considered endemic for Chiloé Island in southern Chile. The aim of the present work was to detect and determine the prevalence of chiggers on different rodent species captured in probable sites for the transmission of orientiae responsible for scrub typhus on Chiloé Island in southern Chile and to molecularly examine collected chiggers for the presence of Orientia DNA.

Methodology/Principal findings

During the austral summer 2018, rodents were live-trapped in six sites and examined for chigger infestation. All study sites were rural areas on Chiloé Island, previously identified as probable localities where human cases acquired the scrub typhus. During a total of 4,713 trap-nights, 244 rodents of seven species were captured: the most abundant was Abrothrix olivacea. Chiggers were detected on all seven rodent species with a 55% prevalence rate. Chiggers showed low host specificity and varied according to site specific host abundance. Three genera of trombiculids were identified. Herpetacarus was the most abundant genus (93%), prevalent in five of the six sites. Infestation rates showed site specific differences, which were statistically significant using a GLM model with binomial errors. Molecular analyses proved that 21 of 133 (15.8%) mite pools were positive for Orientia species, all of them belonged to the genus Herpetacarus.

Conclusions/Significance

This study firstly reports the presence of different rodent-associated chigger mites positive for Orientia sp., in a region endemic for scrub typhus in southern Chile. Herpetacarus and two other genera of mites were found with high infestation rates of rodents in sites previously identified as probable exposure of scrub typhus cases. A substantial percentage of mite pools were positive for Orientia DNA, suggesting that chigger mites serve as vectors and reservoirs of this emerging zoonosis in South America.

Scrub typhus is a chigger-transmitted zoonotic infection caused by Orientia species, which is endemic to the tsutsugamushi triangle in Asia-Pacific region. Recently, a focus of scrub typhus in South America has been confirmed on Chiloé Island in southern Chile. However, the vectors of scrub typhus in this region remain unknown. We undertook a survey to study the presence of chiggers on different rodent species in areas identified as probable sites of exposure to scrub typhus on Chiloé Island. The study showed that 55% of rodents were infested by trombiculids. Three mite genera were identified, of which Herpetacarus was the most abundant. Chiggers showed low host specificity, but spatial differences. Using molecular techniques, the trombiculid mites were found to be infected with Orientia species. These findings suggest that chigger mites play a role in the life cycle and transmission of this emerging infectious disease in Chile.

The Draft Genome of Hariotina reticulata (Sphaeropleales, Chlorophyta) Provides Insight into the Evolution of Scenedesmaceae

Hariotina reticulata P. A. Dangeard 1889 (Sphaeropleales, Chlorophyta) is a common member of the summer phytoplankton of meso- to highly eutrophic water bodies with a worldwide distribution. Here, we report the draft whole-genome shotgun sequencing of H. reticulata strain SAG 8.81. The final assembly comprises 107,596,510bp with over 15,219 scaffolds (>100bp). This whole-genome project is publicly available in the CNSA (https://db.cngb.org/cnsa/) of CNGBdb under the accession number CNP0000705.

Comparison of two DNA extraction methods from larvae, pupae, and adults of Aedes aegypti

Mosquitoes are the most important arthropods from the point of view of public health, due to the fact that they can transmit a large number of pathogens which can cause diseases to humans and animals. Aedes aegypti (L.) is one of the most important vector species in the world, since it can transmit numerous pathogens such as dengue, Zika, and chikungunya. Therefore, studies involving the molecular aspects of this and other mosquitoes species are currently increasing. In this report, we describe the comparison between two DNA extraction techniques, Chelex and cetyltrimethylammonium bromide (CTAB), for carrying out DNA extraction in larvae, pupae and adult female of Ae. aegypti. The Chelex technique was superior in the amount and purity of DNA as compared to the CTAB technique in the three life stages we tested.

Cross-amplification of microsatellite loci in the cacti species from Brazilian Chaco

Cactaceae species are an important component of the Brazilian Chaco landscape. Sixteen species are reported to this region, including 13 genera representing three Cactaceae subfamilies. All these species are native and have been locally threatened by the advance of the deforestation, which can negatively impact their genetic diversity. In order to test genetic markers that can potentially be used to screen the population diversity of these species, we checked the cross-amplification performance of 27 nuclear and 23 plastid microsatellite loci in all 16 cacti species from Brazilian Chaco. We tested the cross-amplification of the 50 microsatellite (SSR) loci in one specimen of each cacti species and considered it successful when at least one band of the expected size was generated. Thirteen species (81%) had at least 18 nuclear microsatellite loci amplified, while seven species (43%) had at least 11 chloroplast microsatellite loci amplified. We also reviewed current knowledge of SSR studies with Cactaceae in 50 studies available in the Web of Science^®, and found that only five cacti species that occur in the Brazilian Chaco have representatives of the same genus with described SSR loci. The high cross-amplification rates indicated that these microsatellites markers can be helpful for future population genetic studies with cacti species from the Brazilian Chaco. Since their diversity levels and gene flow patterns are still poorly known, analyses with universal and transferable markers provide important tools to guide conservation efforts on this highly neglected region.