[Genome-wide identification and expression analysis of TCP gene family of Andrographis paniculata under abiotic stress].

Andrographis paniculata is an important medicinal plant in the Lingnan region of China, which has the functions of clearing heat, removing toxins, and resisting bacteria and inflammation. The TCP gene family is a class of transcription factors that regulate plant growth, development, and stress response. In order to analysis the role of the TCP gene family under abiotic stress in A. paniculata, this study identified the TCP gene family of A. paniculata at the genome-wide level and analyzed its expression pattern in response to abiotic stress. The results showed that the A. paniculata TCP gene family had 23 members, with length of amino acid ranging from 136 to 508, the relative molecular mass between 14 854.71 and 55 944.90 kDa, and the isoelectric point between 5.67 and 10.39. All members were located in the nucleus and unevenly distributed on 13 chromosomes. Phylogenetic analysis classified them into three subfamilies: PCF, CIN and CYC/TB1. Gene structure and conserved motif analysis showed that most members of the TCP gene family contained motif 1, motif 2, motif 3 in the same order and 1-3 CDS. The analysis of promoter cis-acting elements showed that the transcriptional expression of the TCP gene family in A. paniculata might be induced by light, hormones, and adversity stress. In light of the expression pattern analysis and qRT-PCR verification, the expression of ApTCP4, ApTCP5, ApTCP6, and ApTCP11 involved in response by various abiotic stresses such as drought, high temperature, and MeJA. This study lays the foundation for in-depth exploration of the functions of A. paniculata TCP genes in response to abiotic stress.

Effects of a mixture of glycerol monolaurate and cinnamaldehyde supplementation on laying performance, egg quality, and antioxidant status in laying hens.

BACKGROUND: This study aimed to determine the effects of a mixture of glycerol monolaurate and cinnamaldehyde (GCM) supplementation on the laying performance, egg quality, antioxidant capacity, and serum parameters of laying hens. A total of 1120 14-week-old Jingfen-1 strain laying hens with similar performance were randomly allocated to four dietary treatments: control, and GCM groups supplemented with 250, 500, or 1000 mg kg-1 for 12 weeks. RESULTS: Compared with the control group, GCM-supplemented groups significantly reduced (P < 0.05) the rate of unqualified eggs of laying hens aged 17-24 weeks. Supplementation of GCM significantly increased (P < 0.05) yolk color and serum glutathione peroxidase (GSH-Px) activity but decreased (P < 0.05) the hydrogen peroxide (H2 O2 ) content in the serum of laying hens at the age of 20 weeks. Furthermore, groups supplemented with GCM showed a significant increase (P < 0.05) in Haugh unit, yolk color, activities of total superoxide dismutase and GSH-Px, and the glucose content in serum, and a decrease (P < 0.05) in the content of urea nitrogen and H2 O2 and malondialdehyde in serum of laying hens at the age of 24 weeks. 500 mg kg-1 GCM supplementation significantly increased (P < 0.05) the number of large white follicles and 1000 mg kg-1 GCM supplementation decreased the number of large yellow follicles in 28-week-old laying hens. CONCLUSION: These results indicated that GCM supplementation has positive effects on reducing egg loss and improving egg quality in the early laying period of laying hens. © 2023 Society of Chemical Industry.

Ganoderic acid C2 exerts the pharmacological effects against cyclophosphamide-induced immunosuppression: a study involving molecular docking and experimental validation.

Triterpenoids, as the main active ingredient of Ganoderma lucidum fermented extract, exert multiple pharmacological activities, including immunomodulatory properties. Our study aimed to reveal the pharmacological effects and potential mechanisms of Ganoderic acid C2 (GAC) against cyclophosphamide (CY)-associated immunosuppression. Target genes were collected from several public databases, including the DisGeNET, Comparative Toxicogenomics Database, GeneCards, and PharmMapper. STRING database was used to construct the protein-protein interaction of network. Subsequently, molecular docking was carried out to visualize the protein-GAC interactions. Experimental validations, including ELISA and qRT-PCR were performed to confirm the pharmacological activities of GAC on CY-induced immunosuppression model. A total of 56 GAC-related targets were identified to be closely associated with CY-induced immunosuppression. Enrichment analyses results revealed that these targets were mainly involved in immune and inflammatory response-related pathways. STAT3 and TNF were identified as the core targets of GAC. Molecular docking indicated that GAC combined well with STAT3 and TNF protein. In addition, animal experiments indicated that GAC improved immunity as well as STAT3 and TNF genes expression in CY-induced immunosuppression, which further verified the prediction through bioinformatics analysis and molecular docking. We successfully revealed the potential therapeutics mechanisms underlying the effect of GAC against CY-induced immunosuppression based on the combination of bioinformatics analysis, molecular docking, and animal experiments. Our findings lay a theoretical foundation for the in-depth development and utilization of Ganoderma lucidum fermentation product in the future, and also provide theoretical guidance for the development of innovative drugs that assist in improving immunity.

Genomic-wide identification and expression analysis of R2R3-MYB transcription factors related to flavonol biosynthesis in Morinda officinalis.

BACKGROUND: The R2R3-MYB transcription factors are a crucial and extensive gene family in plants, which participate in diverse processes, including development, metabolism, defense, differentiation, and stress response. In the Lingnan region of China, Morinda officinalis is extensively grown and is renowned for its use as both a medicinal herb and food source. However, there are relatively few reports on the R2R3-MYB transcription factor family in M.officinalis. RESULTS: In this study, we identified 97 R2R3-MYB genes in the genome of Morinda officinalis and classified them into 32 subgroups based on phylogenetic comparison with Arabidopsis thaliana. The lack of recent whole-genome duplication events in M.officinalis may be the reason for the relatively few members of the R2R3-MYB family. We also further analyzed the physical and chemical characteristics, conserved motifs, gene structure, and chromosomal location. Gene duplication events found 21 fragment duplication pairs and five tandem duplication event R2R3-MYB genes in M.officinalis may also affect gene family expansion. Based on phylogenetic analysis, cis-element analysis, co-expression analysis and RT-qPCR, we concluded that MoMYB33 might modulate flavonol levels by regulating the expression of 4-coumarate-CoA ligase Mo4CL2, chalcone isomerase MoCHI3, and flavonol synthase MoFLS4/11/12. MoMYB33 and AtMYB111 showed the highest similarity of 79% and may be involved in flavonol synthase networks by the STRING database. Moreover, we also identified MoMYB genes that respond to methyl Jasmonate (MeJA) and abscisic acid (ABA) stress by RT-qPCR. CONCLUSIONS: This study offers a thorough comprehension of R2R3-MYB in M.officinalis, which lays the foundation for the regulation of flavonol synthesis and the response of MoMYB genes to phytohormones in M.officinalis.

Gap-free genome assembly and comparative analysis reveal the evolution and anthocyanin accumulation mechanism of Rhodomyrtus tomentosa.

Rhodomyrtus tomentosa is an important fleshy-fruited tree and a well-known medicinal plant of the Myrtaceae family that is widely cultivated in tropical and subtropical areas of the world. However, studies on the evolution and genomic breeding of R. tomentosa were hindered by the lack of a reference genome. Here, we presented a chromosome-level gap-free T2T genome assembly of R. tomentosa using PacBio and ONT long read sequencing. We assembled the genome with size of 470.35 Mb and contig N50 of ~43.80 Mb with 11 pseudochromosomes. A total of 33 382 genes and 239.31 Mb of repetitive sequences were annotated in this genome. Phylogenetic analysis elucidated the independent evolution of R. tomentosa starting from 14.37MYA and shared a recent WGD event with other Myrtaceae species. We identified four major compounds of anthocyanins and their synthetic pathways in R. tomentosa. Comparative genomic and gene expression analysis suggested the coloring and high anthocyanin accumulation in R. tomentosa tends to be determined by the activation of anthocyanin synthesis pathway. The positive selection and up-regulation of MYB transcription factors were the implicit factors in this process. The copy number increase of downstream anthocyanin transport-related OMT and GST gene were also detected in R. tomentosa. Expression analysis and pathway identification enriched the importance of starch degradation, response to stimuli, effect of hormones, and cell wall metabolism during the fleshy fruit development in Myrtaceae. Our genome assembly provided a foundation for investigating the origins and differentiation of Myrtaceae species and accelerated the genetic improvement of R. tomentosa.

Integration of high-throughput omics technologies in medicinal plant research: The new era of natural drug discovery.

Medicinal plants are natural sources to unravel novel bioactive compounds to satisfy human pharmacological potentials. The world's demand for herbal medicines is increasing year by year; however, large-scale production of medicinal plants and their derivatives is still limited. The rapid development of modern technology has stimulated multi-omics research in medicinal plants, leading to a series of breakthroughs on key genes, metabolites, enzymes involved in biosynthesis and regulation of active compounds. Here, we summarize the latest research progress on the molecular intricacy of medicinal plants, including the comparison of genomics to demonstrate variation and evolution among species, the application of transcriptomics, proteomics and metabolomics to explore dynamic changes of molecular compounds, and the utilization of potential resources for natural drug discovery. These multi-omics research provide the theoretical basis for environmental adaptation of medicinal plants and allow us to understand the chemical diversity and composition of bioactive compounds. Many medicinal herbs' phytochemical constituents and their potential health benefits are not fully explored. Given their large diversity and global distribution as well as the impacts of growth duration and environmental factors on bioactive phytochemicals in medicinal plants, it is crucial to emphasize the research needs of using multi-omics technologies to address basic and applied problems in medicinal plants to aid in developing new and improved medicinal plant resources and discovering novel medicinal ingredients.

The first high-quality chromosome-level genome assembly of Phyllanthaceae (Phyllanthus cochinchinensis) provides insights into flavonoid biosynthesis.

MAIN CONCLUSION: We report the genome assembly of P. cochinchinensis, as the first high-quality chromosome-level genome of Phyllanthaceae which is rich in medicinal plants. Phyllanthus cochinchinensis, a member of the Phyllanthaceae, is one of the famous medicinal plants in South China. Here, we report a de novo chromosome-level genome assembly for P. cochinchinensis using a combination of Nanopore and Illumina sequencing technologies. In total, the assembled genome consists of 284.88 Mb genomic sequences with a contig N50 of 10.32 Mb, representing ~ 95.49% of the estimated genome size. By applying Hi-C data, 13 pseudochromosomes of P. cochinchinensis were constructed, covering ~ 99.87% of the assembled sequences. The genome is annotated with 59.12% repetitive sequences and 20,836 protein-coding genes. Whole-genome duplication of P. cochinchinensis is likely shared with Ricinus communis as well as Vitis vinifera. Homologous genes within the flavonoid pathway for P. cochinchinensis were identified and copy numbers and expression level of related genes revealed potential critical genes involved in flavonoid biosynthesis. This study provides the first whole-genome sequence for the Phyllanthaceae, confirms the evolutionary status of Phyllanthus from the genomic level, and provides foundations for accelerating functional genomic research of species from Phyllanthus.

MicroRNAs in Medicinal Plants.

Medicinal plant microRNAs (miRNAs) are an endogenous class of small RNA central to the posttranscriptional regulation of gene expression. Biosynthetic research has shown that the mature miRNAs in medicinal plants can be produced from either the standard messenger RNA splicing mechanism or the pre-ribosomal RNA splicing process. The medicinal plant miRNA function is separated into two levels: (1) the cross-kingdom level, which is the regulation of disease-related genes in animal cells by oral intake, and (2) the intra-kingdom level, which is the participation of metabolism, development, and stress adaptation in homologous or heterologous plants. Increasing research continues to enrich the biosynthesis and function of medicinal plant miRNAs. In this review, peer-reviewed papers on medicinal plant miRNAs published on the Web of Science were discussed, covering a total of 78 species. The feasibility of the emerging role of medicinal plant miRNAs in regulating animal gene function was critically evaluated. Staged progress in intra-kingdom miRNA research has only been found in a few medicinal plants, which may be mainly inhibited by their long growth cycle, high demand for growth environment, immature genetic transformation, and difficult RNA extraction. The present review clarifies the research significance, opportunities, and challenges of medicinal plant miRNAs in drug development and agricultural production. The discussion of the latest results furthers the understanding of medicinal plant miRNAs and helps the rational design of the corresponding miRNA/target genes functional modules.

The complete chloroplast genome sequence of Clerodendrum cyrtophyllum from Guangzhou, China.

Clerodendrum cyrtophyllum is a well-known medicinal plant in southern China. Here, we presented the complete chloroplast (cp) genome of C. cyrtophyllum using Illumina high-throughput sequencing technology. The C. cyrtophyllum cp genome size is 152,004 bp with 38.13% GC content, including a pair of inverted repeat regions (IR, 51,592 bp) separated by a large single copy (LSC, 86,480 bp) and a small single copy region (SSC, 18,425 bp). It possesses 87 protein-coding genes, 37 tRNA genes and eight rRNA genes. Phylogenetic analysis fully shows that C. cyrtophyllum is closely related to Clerodendrum bungei and Clerodendrum lindleyi. Overall, the complete cp genome sequence of C. cyrtophyllum provides a valuable resource for genetic diversity, phylogenetic relationship, and species identification.

Complete genome sequence and phylogenetic analysis of medicinal plant Abrus cantoniensis for evolutionary research and germplasm utilization.

Abrus cantoniensis Hance, a native medicinal plant in southern China, is officially recorded in the Chinese Pharmacopoeia. Here, we presented the first high-quality genome in Abrus genus, A. cantoniensis genome, as well as the detailed genomic information. The assembled genome size was 381.27 Mb with a scaffold N50 of 18.95 Mb, and 98.97% of the assembled sequences were anchored on 11 pseudochromosomes. The A. cantoniensis genome comprised 25,058 protein-coding genes and 45.12% of the assemblies were repetitive sequences. Comparative genome analysis suggested that chromosome translocation and inversion played an important role in the differentiation of Abrus. In addition, 24 toxin-related genes were identified, which formed two tandem gene clusters on chromosomes 2 and 3. The chromosome-level genome of A. cantoniensis obtained in this work provides a valuable resource for understanding the evolution, active ingredient biosynthesis, and genetic improvement for A. cantoniensis and Abrus species.

The complete chloroplast genome sequence of the medicinal plant Abrus pulchellus subsp. cantoniensis: genome structure, comparative and phylogenetic relationship analysis.

Abrus pulchellus subsp. cantoniensis, an endemic medicinal plant in southern China, is clinically used to treat jaundice hepatitis, cholecystitis, stomachache and breast carbuncle. Here, we assembled and analyzed the first complete chloroplast (cp) genome of A. pulchellus subsp. cantoniensis. The A. pulchellus subsp. cantoniensis cp genome size is 156,497 bp with 36.5% GC content. The cp genome encodes 130 genes, including 77 protein-coding genes, 30 tRNA genes and four rRNA genes, of which 19 genes are duplicated in the inverted repeats (IR) regions. A total of 30 codons exhibited codon usage bias with A/U-ending. Moreover, 53 putative RNA editing sites were predicted in 20 genes, all of which were cytidine to thymine transitions. Repeat sequence analysis identified 45 repeat structures and 125 simple-sequence repeats (SSRs) in A. pulchellus subsp. cantoniensis cp genome. In addition, 19 mononucleotides (located in atpB, trnV-UAC, ycf3, atpF, rps16, rps18, clpP, rpl16, trnG-UCC and ndhA) and three compound SSRs (located in ndhA, atpB and rpl16) showed species specificity between A. pulchellus subsp. cantoniensis and Abrus precatorius, which might be informative sources for developing molecular markers for species identification. Furthermore, phylogenetic analysis inferred that A. pulchellus subsp. cantoniensis was closely related to A. precatorius, and the genus Abrus formed a subclade with Canavalia in the Millettioid/Phaseoloid clade. These data provide a valuable resource to facilitate the evolutionary relationship and species identification of this species.

[Identification and expression analysis of R2R3-MYB gene family in Andrographis paniculata].

The plant growth, development, and secondary metabolism are regulated by R2 R3-MYB transcription factors. This study identified the R2 R3-MYB genes in the genome of Andrographis paniculata and analyzed the chromosomal localization, gene structure, and conserved domains, phylogenetic relationship, and promoter cis-acting elements of these R2 R3-MYB genes. Moreover, the gene expression profiles of R2 R3-MYB genes under abiotic stress and hormone treatments were generated by RNA-seq and validated by qRT-PCR. The results showed that A. paniculata contained 73 R2 R3-MYB genes on 21 chromosomes. These members belonged to 34 subfamilies, 19 of which could be classified into the known subfamilies in Arabidopsis thaliana. The 73 R2 R3-MYB members included 36 acidic proteins and 37 basic proteins, with the lengths of 148-887 aa. The domains, motifs, and gene structures of R2 R3-MYBs in A. paniculata were conserved. The promoter regions of these genes contains a variety of cis-acting elements related to the responses to environmental factors and plant hormones including light, ABA, MeJA, and drought. Based on the similarity of functions of R2 R3-MYBs in the same subfamily and the transcription profiles, ApMYB13/21/35/67/73(S22) may regulate drought stress through ABA pathway; ApMYB20(S11) and ApMYB55(S2) may play a role in the response of A. paniculata to high temperature and UV-C stress; ApMYB5(S7) and ApMYB33(S20) may affect the accumulation of andrographolide by regulating the expression of key enzymes in the MEP pathway. This study provides theoretical reference for further research on the functions of R2 R3-MYB genes in A. paniculata and breeding of A. paniculata varieties with high andrographolide content.

Chromosome-level genome assembly of Gynostemma pentaphyllum provides insights into gypenoside biosynthesis.

Gynostemma pentaphyllum (Thunb.) Makino is an economically valuable medicinal plant belonging to the Cucurbitaceae family that produces the bioactive compound gypenoside. Despite several transcriptomes having been generated for G. pentaphyllum, a reference genome is still unavailable, which has limited the understanding of the gypenoside biosynthesis and regulatory mechanism. Here, we report a high-quality G. pentaphyllum genome with a total length of 582 Mb comprising 1,232 contigs and a scaffold N50 of 50.78 Mb. The G. pentaphyllum genome comprised 59.14% repetitive sequences and 25,285 protein-coding genes. Comparative genome analysis revealed that G. pentaphyllum was related to Siraitia grosvenorii, with an estimated divergence time dating to the Paleogene (∼48 million years ago). By combining transcriptome data from seven tissues, we reconstructed the gypenoside biosynthetic pathway and potential regulatory network using tissue-specific gene co-expression network analysis. Four UDP-glucuronosyltransferases (UGTs), belonging to the UGT85 subfamily and forming a gene cluster, were involved in catalyzing glycosylation in leaf-specific gypenoside biosynthesis. Furthermore, candidate biosynthetic genes and transcription factors involved in the gypenoside regulatory network were identified. The genetic information obtained in this study provides insights into gypenoside biosynthesis and lays the foundation for further exploration of the gypenoside regulatory mechanism.

A high-quality genome assembly of Morinda officinalis, a famous native southern herb in the Lingnan region of southern China.

Morinda officinalis is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of southern China. Its dried roots (called bajitian in traditional Chinese medicine) are broadly used to treat various diseases, such as impotence and rheumatism. Here, we report a high-quality chromosome-scale genome assembly of M. officinalis using Nanopore single-molecule sequencing and Hi-C technology. The assembled genome size was 484.85 Mb with a scaffold N50 of 40.97 Mb, and 90.77% of the assembled sequences were anchored on eleven pseudochromosomes. The genome includes 27,698 protein-coding genes, and most of the assemblies are repetitive sequences. Genome evolution analysis revealed that M. officinalis underwent core eudicot γ genome triplication events but no recent whole-genome duplication (WGD). Likewise, comparative genomic analysis showed no large-scale structural variation after species divergence between M. officinalis and Coffea canephora. Moreover, gene family analysis indicated that gene families associated with plant-pathogen interactions and sugar metabolism were significantly expanded in M. officinalis. Furthermore, we identified many candidate genes involved in the biosynthesis of major active components such as anthraquinones, iridoids and polysaccharides. In addition, we also found that the DHQS, GGPPS, TPS-Clin, TPS04, sacA, and UGDH gene families-which include the critical genes for active component biosynthesis-were expanded in M. officinalis. This study provides a valuable resource for understanding M. officinalis genome evolution and active component biosynthesis. This work will facilitate genetic improvement and molecular breeding of this commercially important plant.

Resorcinol derivatives with α-glucosidase inhibitory activities from Syzygium samarangense.

Nine resorcinol derivatives including two new ones, 5-[(8Z,11Z,14Z)-nonadeca-8,11,14-trienyl] resorcinol (1) and 5-[(8Z,11Z,14E)-heptadeca-8,11,14-trienyl] resorcinol (2), were isolated from the leaves of Syzygium samarangense. The new structures were elucidated by means of extensive spectroscopic techniques including interpretation of 1D and 2D NMR spectra. Among them, compounds 3, 4, 6 and 7 exhibited significant α-glucosidase inhibitory activities with IC50 of 3.16, 3.16, 2.34 and 0.99 µM, respectively. This finding provides evidence that resorcinol derivatives with long aliphatic chain function as new promising antidiabetic alternatives.

The complete chloroplast genome sequence of the medicinal plant Mesona chinensis (Labiatae).

Mesona chinensis is an important traditional Chinese medicine and edible plant resource in China. In this work, we sequenced the complete chloroplast genome of M. chinensis and researched its evolution. The genome size is 152,547 bp, with 37.89% GC content, including a large single copy region (LSC) of 83,482 bp, a small single copy region (SSC) of 17,725 bp and a pair of inverted repeats region (IRs) of 25,670 bp. The complete chloroplast genome was predicted to encode 131 genes, consist of 86 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Phylogenetic analysis showed that M. chinensis was closely related to other Labiatae species Ocimum tenuiflorum.

The complete chloroplast genome sequence of medicinal plant Alpinia chinensis (Retz.) Rosc.

Alpinia chinensis (Retz.) Rosc is one of Chinese tradition herbal medicine and edible plant in China. In this report, we sequenced the complete chloroplast genome of A. chinensis. Through the assembly annotation of genome with high-throughput sequencing data, which help us to research the evolution. The length of chloroplast sequences was 163,590 bp with a large single-copy region (LSC) and a small single-copy region (SSC), also, two inverted repeat region A (IR), whose length was 88,951, 15,299, and 29,670 bp, respectively. A total of 138 genes were predicted in the complete chloroplast genome, with 36.4% GC content, including 93 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. From the phylogenetic analysis, we could conclude that A. chinensis (Retz.) Rosc. was close to Alpinia oxyphylla in Zingiberaceae.

The complete chloroplast genome sequence of Acanthopanax trifoliatus (Linn.) Merr.

Acanthopanax trifoliatus (Linn.) Merr. is an edible vegetables and medicinal plant from Asian countries. In this study, the complete chloroplast genome of A. trifoliatus was assembled and annotated by high-throughput sequencing. The total chloroplast genome size of A. trifoliatus was 156,716 bp, containing a large single-copy (LSC) region of 86,672 bp, a small single-copy (SSC) region of 18,174 bp, and a pair of inverted repeat regions of 25,935 bp. A total of 134 genes were predicted in the chloroplast genome of A. trifoliatus, including 89 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis showed that A. trifoliatus was closely related to Eleutherococcus gracilistylus.

Field Evaluation of Integrated Management for Mitigating Citrus Huanglongbing in Florida.

Citrus huanglongbing (HLB) is extremely difficult to control because the psyllid-transmitted bacterial pathogen resides inside the citrus phloem and the disease is systemic. In Florida, the nine billion dollar citrus industry has been significantly impacted by severe HLB epidemics. To combat citrus HLB, in this study we implemented an integrated strategy that includes chemotherapy, thermotherapy, and additional nutrition treatment in three different field trials over three consecutive years. In these trials, only trees already showing HLB symptoms with Ct values ranging from 25.1 to 27.7 were selected for treatments. To assess the complex interactions, we used several methods for evaluating the effectiveness of integrated management, including the slopes (b) of the Ct increase (dy/dt), the pathogenic index (PI) and the decline index (DI) from Ct value and tree scores, and the therapeutic efficacies from PI and DI. This comprehensive analysis showed that most of the tested chemicals were effective to some degree in killing or suppressing the Las bacterium, with higher therapeutic efficacies seen for Grove B, where citrus trees were severely affected by HLB, and it had a higher number of psyllids, relative to Grove E and P in the first 2 years. Trunk-injected penicillin G potassium was the most effective chemical treatment in all groves, followed by Oxytetracycline Calcium Complex, and Silver Nitrate delivered as foliar sprays. Although the steam heat treatment and additional nutrition did not eliminate or suppress Las over the long term, these treatments did positively affect tree growth and recovery in the short term. Overall, our results provide new insights into HLB control method and strategy for integrated management for HLB epidemic plantations.

Draft genome sequence of the Tibetan medicinal herb Rhodiola crenulata.

Rhodiola crenulata, a well-known medicinal Tibetan herb, is mainly grown in high-altitude regions of the Tibet, Yunnan, and Sichuan provinces in China. In the past few years, increasing numbers of studies have been published on the potential pharmacological activities of R. crenulata, strengthening our understanding into its putitive active ingredient composition, pharmacological activity, and mechanism of action. These findings also provide strong evidence supporting the important medicinal and economical value of R. crenulata. Consequently, some Rhodiola species are becoming endangered because of overexploitation and environmental destruction. However, little is known about the genetic and genomic information of any Rhodiola species. Here we report the first draft assembly ofthe R. crenulata genome, which was 344.5 Mb (25.7 Mb Ns), accounting for 82% of the estimated genome size, with a scaffold N50 length of 144.7 kb and a contig N50 length of 25.4 kb. The R. crenulata genome is not only highly heterozygous but also highly repetitive, with ratios of 1.12% and 66.15%, respectively, based on the k-mer analysis. Furthermore, 226.6 Mb of transposable elements were detected, of which 77.03% were long terminal repeats. In total, 31 517 protein-coding genes were identified, capturing 86.72% of expected plant genes in BUSCO. Additionally, 79.73% of protein-coding genes were functionally annotated. R. crenulata is an important medicinal plant and also a potentially interesting model species for studying the adaptability of Rhodiola species to extreme environments. The genomic sequences of R. crenulata will be useful for understanding the evolutionary mechanism of the stress resistance gene and the biosynthesis pathways of the different medicinal ingredients, for example, salidroside in R. crenulata.