Cloning and functional mechanism of the dwarf gene gba affecting stem elongation and cellulose biosynthesis in jute (Corchorus olitorius).

Plant height (PH) is an important factor affecting bast fiber yield in jute. Here, we report the mechanism of dwarfism in the 'Guangbaai' (gba) of jute. The mutant gba had shorter internode length and cell length compared to the standard cultivar 'TaiZi 4' (TZ4). Exogenous GA3 treatment indicated that gba is a GA-insensitive dwarf mutant. Quantitative trait locus (QTL) analysis of three PH-related traits via a high-density genetic linkage map according to re-seq showed that a total of 25 QTLs were identified, including 13 QTLs for PH, with phenotypic variation explained ranging from 2.42 to 74.16%. Notably, the functional mechanism of the candidate gene CoGID1a, the gibberellic acid receptor, of the major locus qPHIL5 was evaluated by transgenic analysis and virus-induced gene silencing. A dwarf phenotype-related single nucleotide mutation in CoGID1a was identified in gba, which was also unique to the dwarf phenotype of gba among 57 cultivars. Cogid1a was unable to interact with the growth-repressor DELLA even in the presence of highly accumulated gibberellins in gba. Differentially expressed genes between transcriptomes of gba and TZ4 after GA3 treatment indicated up-regulation of genes involved in gibberellin and cellulose synthesis in gba. Interestingly, it was found that up-regulation of CoMYB46, a key transcription factor in the secondary cell wall, by the highly accumulated gibberellins in gba promoted the expression of cellulose synthase genes CoCesA4 and CoCesA7. These findings provide valuable insights into fiber development affected by endogenous gibberellin accumulation in plants.

Genomic and cytogenetic analyses reveal satellite repeat signature in allotetraploid okra (Abelmoschus esculentus).

BACKGROUND: Satellite repeats are one of the most rapidly evolving components in eukaryotic genomes and play vital roles in genome regulation, genome evolution, and speciation. As a consequence, the composition, abundance and chromosome distribution of satellite repeats often exhibit variability across various species, genome, and even individual chromosomes. However, we know little about the satellite repeat evolution in allopolyploid genomes. RESULTS: In this study, we investigated the satellite repeat signature in five okra (Abelmoschus esculentus) accessions using genomic and cytogenetic methods. In each of the five accessions, we identified eight satellite repeats, which exhibited a significant level of intraspecific conservation. Through fluorescence in situ hybridization (FISH) experiments, we observed that the satellite repeats generated multiple signals and exhibited variations in copy number across chromosomes. Intriguingly, we found that five satellite repeats were interspersed with centromeric retrotransposons, signifying their involvement in centromeric satellite repeat identity. We confirmed subgenome-biased amplification patterns of these satellite repeats through existing genome assemblies or dual-color FISH, indicating their distinct dynamic evolution in the allotetraploid okra subgenome. Moreover, we observed the presence of multiple chromosomes harboring the 35 S rDNA loci, alongside another chromosomal pair carrying the 5 S rDNA loci in okra using FISH assay. Remarkably, the intensity of 35 S rDNA hybridization signals varied among chromosomes, with the signals predominantly localized within regions of relatively weak DAPI staining, associated with GC-rich heterochromatin regions. Finally, we observed a similar localization pattern between 35 S rDNA and three satellite repeats with high GC content and confirmed their origin in the intergenic spacer region of the 35 S rDNA. CONCLUSIONS: Our findings uncover a unique satellite repeat signature in the allotetraploid okra, contributing to our understanding of the composition, abundance, and chromosomal distribution of satellite repeats in allopolyploid genomes, further enriching our understanding of their evolutionary dynamics in complex allopolyploid genomes.

Evolution and expression analysis of the caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) gene family in jute (Corchorus L.).

BACKGROUND: Jute is considered one of the most important crops for fiber production and multipurpose usages. Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) is a crucial enzyme involved in lignin biosynthesis in plants. The potential functions of CCoAOMT in lignin biosynthesis of jute have been reported in several studies. However, little is known about the evolution of the CCoAOMT gene family, and either their expression level at different developing stages in different jute cultivars, as well as under abiotic stresses including salt and drought stress. RESULTS: In the present study, 66 CCoAOMT genes from 12 species including 12 and eight CCoAOMTs in Corchorus olitorius and C. capsularis were identified. Phylogenetic analysis revealed that CCoAOMTs could be divided into six groups, and gene expansion was observed in C. olitorius. Furthermore, gene expression analysis of developing jute fibers was conducted at different developmental stages (15, 30, 45, 60, and 90 days after sowing [DAS]) in six varieties (Jute-179 [J179], Lubinyuanguo [LB], and Qiongyueqing [QY] for C. capsularis; Funong No.5 [F5], Kuanyechangguo [KY], and Cvlv [CL] for C. olitorius). The results showed that CCoAOMT1 and CCoAOMT2 were the dominant genes in the CCoAOMT family. Of these two dominant CCoAOMTs, CCoAOMT2 showed a constitutive expression level during the entire growth stages, while CCoAOMT1 exhibited differential expression patterns. These two genes showed higher expression levels in C. olitorius than in C. capsularis. The correlation between lignin content and CCoAOMT gene expression levels indicated that this gene family influences the lignin content of jute. Using real-time quantitative reverse transcription PCR (qRT-PCR), a substantial up-regulation of CCoAOMTs was detected in stem tissues of jute 24 h after drought treatment, with an up to 17-fold increase in expression compared to that of untreated plants. CONCLUSIONS: This study provides a basis for comprehensive genomic studies of the entire CCoAOMT gene family in C. capsularis and C. olitorius. Comparative genomics analysis among the CCoAOMT gene families of 12 species revealed the close evolutionary relationship among Corchorus, Theobroma cacao and Gossypium raimondii. This study also shows that CCoAOMTs are not only involved in lignin biosynthesis, but also are associated with the abiotic stress response in jute, and suggests the potential use of these lignin-related genes to genetically improve the fiber quality of jute.

Genome-wide association study reveals loci and candidate genes of flowering time in jute (Corchorus L.).

Suitable flowering time can improve fiber yield and quality, which is of great significance for jute biological breeding. In this study, 242 jute accessions were planted in Fujian for 2 consecutive years, and 244,593 SNPs distributed in jute genome were used for genome-wide association analysis of flowering time. A total of 19 candidate intervals (P < 0.0001) were identified by using GLM and FaST-LMM and were significantly associated with flowering time, with phenotypic variation explained (PVE) ranging from 5.8 to 18.61%. Six stable intervals that were repeatedly detected in different environments were further identified by the linkage disequilibrium heatmap. The most likely 7 candidate genes involved to flowering time were further predicted according to the gene functional annotations. Notably, functional analysis of the candidate gene CcPRR7 of the major loci qFT-3-1, a key factor in circadian rhythm in the photoperiodic pathway, was evaluated by linkage, haplotype, and transgenic analysis. ß-glucuronidase (GUS) and luciferase (LUC) activity assay of the promoters with two specific haplotypes confirmed that the flowering time can be controlled by regulating the expression of CcPRR7. The model of CcPRR7 involved in the photoperiod regulation pathway under different photoperiods was proposed. These findings provide insights into genetic loci and genes for molecular marker-assisted selection in jute and valuable information for genetically engineering PRR7 homologs in plants. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01435-8.

Novel Insights into Anthocyanin Synthesis in the Calyx of Roselle Using Integrated Transcriptomic and Metabolomic Analyses.

Roselle (Hibiscus sabdariffa L.) is an annual herbaceous plant of the genus Hibiscus in family Malvaceae. Roselle calyxes are rich in anthocyanins, which play important roles in human health. However, limited information is available on anthocyanin biosynthesis in the roselle calyx. In this study, transcriptomic and metabolomic analyses were performed to identify the key genes involved in anthocyanin biosynthesis in the roselle calyx. Three roselle cultivars with different calyx colors, including FZ-72 (red calyx, R), Baitao K (green calyx, G), and MG5 (stripped calyx, S), were used for metabolomic analyses with UPLC-Q-TOF/MS and RNA-seq. Forty-one compounds were quantified, including six flavonoids and 35 anthocyanins. The calyx of FZ-72 (red calyx) had the highest contents of anthocyanin derivatives such as delphinidin-3-O-sambubioside (955.11 µg/g) and cyanidin-3-O-sambubioside (531.37 µg/g), which were responsible for calyx color, followed by those in MG5 (stripped calyx) (851.97 and 330.06 µg/g, respectively). Baitao K (green calyx) had the lowest levels of these compounds. Furthermore, RNA-seq analysis revealed 114,415 differentially expressed genes (DEGs) in the calyxes at 30 days after flowering (DAF) for the corresponding cultivars FZ-72 (R), Baitao K (G), and MG5(S). The gene expression levels in the calyxes of the three cultivars were compared at different flowering stages, revealing 11,555, 11,949, and 7177 DEGs in R vs. G, R vs. S, and G vs. S, respectively. Phenylpropanoid and flavonoid biosynthesis pathways were found to be enriched. In the flavonoid pathway, 29, 28, and 27 genes were identified in G vs. R, G vs. S, and S vs. R, respectively. In the anthocyanin synthesis pathway, two, two, and one differential genes were identified in the three combinations; these differential genes belonged to the UFGT gene family. After joint analysis of the anthocyanin content in roselle calyxes, nine key genes belonging to the CHS, CHI, UFGT, FLS, ANR, DFR, CCoAOMT, SAT, and HST gene families were identified as strongly related to anthocyanin synthesis. These nine genes were verified using qRT-PCR, and the results were consistent with the transcriptome data. Overall, this study presents the first report on anthocyanin biosynthesis in roselle, laying a foundation for breeding roselle cultivars with high anthocyanin content.

Reference genomes of the two cultivated jute species.

Cultivated jute, which comprises the two species Corchorus capsularis and C. olitorius, is the second most important natural fibre source after cotton. Here we describe chromosome-level assemblies of the genomes of both cultivated species. The C. capsularis and C. olitorius assemblies are each comprised of seven pseudo-chromosomes, with the C. capsularis assembly consisting of 336 Mb with 25,874 genes and the C. olitorius assembly containing 361 Mb with 28 479 genes. Although the two Corchorus genomes exhibit collinearity, the genome of C. olitorius contains 25 Mb of additional sequences than that of C. capsularis with 13 putative inversions, which might give a hint to the difference of phenotypic variants between the two cultivated jute species. Analysis of gene expression in isolated fibre tissues reveals candidate genes involved in fibre development. Our analysis of the population structures of 242 cultivars from C. capsularis and 57 cultivars from C. olitorius by whole-genome resequencing resulted in post-domestication bottlenecks occurred ~2000 years ago in these species. We identified hundreds of putative significant marker-trait associations (MTAs) controlling fibre fineness, cellulose content and lignin content of fibre by integrating data from genome-wide association studies (GWAS) with data from analyses of selective sweeps due to natural and artificial selection in these two jute species. Among them, we further validated that CcCOBRA1 and CcC4H1 regulate fibre quality in transgenic plants via improving the biosynthesis of the secondary cell wall. Our results yielded important new resources for functional genomics research and genetic improvement in jute and allied fibre crops.

De novo assembly of transcriptome and genome-wide identification reveal GA3 stress-responsive WRKY transcription factors involved in fiber formation in jute (Corchorus capsularis).

BACKGROUND: WRKY is a group of transcription factors (TFs) that play a vital role in plant growth, development, and stress tolerance. To date, none of jute WRKY (CcWRKY) genes have been identified, even if jute (Corchorus capsularis) is one of the most important natural fiber crops in the world. Little information about the WRKY genes in jute is far from sufficient to understand the molecular mechanism of bast fiber biosynthesis. RESULTS: A total of 244,489,479 clean reads were generated using Illumina paired-end sequencing. De novo assembly yielded 90,982 unigenes with an average length of 714 bp. By sequence similarity searching for known proteins, 48,896 (53.74%) unigenes were annotated. To mine the CcWRKY TFs and identify their potential function, the search for CcWRKYs against the transcriptome data of jute was performed, and a total of 43 CcWRKYs were identified in this study. The gene structure, phylogeny, conserved domain and three-dimensional structure of protein were analyzed by bioinformatics tools of GSDS2.0, MEGA7.0, DNAMAN5.0, WebLogo 3 and SWISS-MODEL respectively. Phylogenetic analysis showed that 43 CcWRKYs were divided into three groups: I, II and III, containing 9, 28, and 6 members respectively, according to the WRKY conserved domain features and the evolution analysis with Arabidopsis thaliana. Gene structure analysis indicated that the number of exons of these CcWRKYs varied from 3 to 11. Among the 43 CcWRKYs, 10, 2, 2, and 14 genes showed higher expression in leaves, stem sticks, stem barks, and roots at the vigorous vegetative growth stage, respectively. Moreover, the expression of 21 of 43 CcWRKYs was regulated significantly with secondary cell wall biosynthesis genes using FPKM and RT-qPCR by GA3 stress to a typical GA3 sensitive dwarf germplasm in comparison to an elite cultivar in jute. The Cis-element analysis showed that promoters of these 21 CcWRKYs had 1 to 4 cis-elements involved in gibberellin-responsiveness, suggesting that they might regulate the development of bast fiber in response to GA3 stress. CONCLUSIONS: A total of 43 CcWRKYs were identified in jute for the first time. Analysis of phylogenetic relationship and gene structure revealed that these CcWRKYs might have a functional diversity. Expression analysis showed 21 TFs as GA3 stress responsive genes. The identification of these CcWRKYs and the characterization of their expression pattern will provide a basis for future clarification of their functions in bast fiber development in jute.

The genome of kenaf (Hibiscus cannabinus L.) provides insights into bast fibre and leaf shape biogenesis.

Kenaf is an annual crop that is widely cultivated as a source of bast (phloem) fibres, the phytoremediation of heavy metal-contaminated farmlands and textile-relevant compounds. Leaf shape played a unique role in kenaf improvement, due to the inheritance as a single locus and the association with fibre development in typical lobed-leaf varieties. Here we report a high-quality genome assembly and annotation for var. 'Fuhong 952' with 1078 Mbp genome and 66 004 protein-coding genes integrating single-molecule real-time sequencing, a high-density genetic map and high-throughput chromosome conformation capture techniques. Gene mapping assists the identification of a homeobox transcription factor LATE MERISTEM IDENTITY 1 (HcLMI1) gene controlling lobed-leaf. Virus-induced gene silencing (VIGS) of HcLMI1 in a lobed-leaf variety was critical to induce round (entire)-like leaf formation. Candidate genes involved in cell wall formation were found in quantitative trait loci (QTL) for fibre yield and quality-related traits. Comparative genomic and transcriptome analyses revealed key genes involved in bast fibre formation, among which there are twice as many cellulose synthase A (CesA) genes due to a recent whole-genome duplication after divergence from Gossypium. Population genomic analysis showed two recent population bottlenecks in kenaf, suggesting domestication and improvement process have led to an increase in fibre biogenesis and yield. This chromosome-scale genome provides an important framework and toolkit for sequence-directed genetic improvement of fibre crops.

High-density genetic map construction and QTLs identification for plant height in white jute (Corchorus capsularis L.) using specific locus amplified fragment (SLAF) sequencing.

BACKGROUND: Genetic mapping and quantitative trait locus (QTL) detection are powerful methodologies in plant improvement and breeding. White jute (Corchorus capsularis L.) is an important industrial raw material fiber crop because of its elite characteristics. However, construction of a high-density genetic map and identification of QTLs has been limited in white jute due to a lack of sufficient molecular markers. The specific locus amplified fragment sequencing (SLAF-seq) strategy combines locus-specific amplification and high-throughput sequencing to carry out de novo single nuclear polymorphism (SNP) discovery and large-scale genotyping. In this study, SLAF-seq was employed to obtain sufficient markers to construct a high-density genetic map for white jute. Moreover, with the development of abundant markers, genetic dissection of fiber yield traits such as plant height was also possible. Here, we present QTLs associated with plant height that were identified using our newly constructed genetic linkage groups. RESULTS: An F8 population consisting of 100 lines was developed. In total, 69,446 high-quality SLAFs were detected of which 5,074 SLAFs were polymorphic; 913 polymorphic markers were used for the construction of a genetic map. The average coverage for each SLAF marker was 43-fold in the parents, and 9.8-fold in each F8 individual. A linkage map was constructed that contained 913 SLAFs on 11 linkage groups (LGs) covering 1621.4 cM with an average density of 1.61 cM per locus. Among the 11 LGs, LG1 was the largest with 210 markers, a length of 406.34 cM, and an average distance of 1.93 cM between adjacent markers. LG11 was the smallest with only 25 markers, a length of 29.66 cM, and an average distance of 1.19 cM between adjacent markers. 'SNP_only' markers accounted for 85.54% and were the predominant markers on the map. QTL mapping based on the F8 phenotypes detected 11 plant height QTLs including one major effect QTL across two cultivation locations, with each QTL accounting for 4.14-15.63% of the phenotypic variance. CONCLUSIONS: To our knowledge, the linkage map constructed here is the densest one available to date for white jute. This analysis also identified the first QTL in white jute. The results will provide an important platform for gene/QTL mapping, sequence assembly, genome comparisons, and marker-assisted selection breeding for white jute.

De novo transcriptome sequence and identification of major bast-related genes involved in cellulose biosynthesis in jute (Corchorus capsularis L.).

BACKGROUND: Jute fiber, extracted from stem bast, is called golden fiber. It is essential for fiber improvement to discover the genes associated with jute development at the vegetative growth stage. However, only 858 EST sequences of jute were deposited in the GenBank database. Obviously, the public available data is far from sufficient to understand the molecular mechanism of the fiber biosynthesis. It is imperative to conduct transcriptomic sequence for jute, which can be used for the discovery of a number of new genes, especially genes involved in cellulose biosynthesis. RESULTS: A total of 79,754,600 clean reads (7.98 Gb) were generated using Illumina paired-end sequencing. De novo assembly yielded 48,914 unigenes with an average length of 903 bp. By sequence similarity searching for known proteins, 27,962 (57.16 %) unigenes were annotated for their function. Out of these annotated unigenes, 21,856 and 11,190 unigenes were assigned to gene ontology (GO) and euKaryotic Ortholog Groups (KOG), respectively. Searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG) indicated that 14,216 unigenes were mapped to 268 KEGG pathways. Moreover, 5 Susy, 3 UGPase, 9 CesA, 18 CSL, 2 Kor (Korrigan), and 12 Cobra unigenes involving in cellulose biosynthesis were identified. Among these unigenes, the unigenes of comp11264_c0 (SuSy), comp24568_c0 (UGPase), comp11363_c0 (CesA), comp11363_c1 (CesA), comp24217_c0 (CesA), and comp23531_c0 (CesA), displayed relatively high expression level in stem bast using FPKM and RT-qPCR, indicating that they may have potential value of dissecting mechanism on cellulose biosynthesis in jute. In addition, a total of 12,518 putative gene-associate SNPs were called from these assembled uingenes. CONCLUSION: We characterized the transcriptome of jute, discovered a broad survey of unigenes associated with vegetative growth and development, developed large-scale SNPs, and analyzed the expression patterns of genes involved in cellulose biosynthesis for bast fiber. All these provides a valuable genomics resource, which will accelerate the understanding of the mechanism of fiber development in jute.

Overexpression of UDP-glucose pyrophosphorylase gene could increase cellulose content in Jute (Corchorus capsularis L.).

In this study, the full-length cDNA of the UDP-glucose pyrophosphorylase gene was isolated from jute by homologous cloning (primers were designed according to the sequence of UGPase gene of other plants) and modified RACE techniques; the cloned gene was designated CcUGPase. Using bioinformatic analysis, the gene was identified as a member of the UGPase gene family. Real-time PCR analysis revealed differential spatial and temporal expression of the CcUGPase gene, with the highest expression levels at 40 and 120d. PCR and Southern hybridization results indicate that the gene was integrated into the jute genome. Overexpression of CcUGPase gene in jute revealed increased height and cellulose content compared with control lines, although the lignin content remained unchanged. The results indicate that the jute UGPase gene participates in cellulose biosynthesis. These data provide an important basis for the application of the CcUGPase gene in the improvement of jute fiber quality.

Genetic diversity of kenaf (Hibiscus cannabinus) evaluated by inter-simple sequence repeat (ISSR).

Understanding genetic diversity is very useful for scientific utilization for breeding. In this study, we estimated the genetic distances in a panel of 84 kenaf accessions collected from 26 countries and regions using ISSR markers. The results of UPGMA analysis showed that kenaf germplasm had abundant genetic variation, with genetic dissimilarity coefficients ranging from 0.01 to 0.62. The in-group dissimilarity coefficient (0.29) was observed in 84 kenaf accessions, and all the accessions could be divided into three groups: cultivars (L1-1), relatively wild species (L1-2 and L1-3), and wild species (the others). Further in-group analysis in group L1-1 (0.19) revealed that the kenaf cultivars could be divided into five subgroups with distinct regional characteristics. It is imperative that genes be exchanged among all kinds of tested varieties from different origins. The results provide a useful basis for kenaf germplasm research and breeding.

Genomic insights of the WRKY genes in kenaf (Hibiscus cannabinus L.) reveal that HcWRKY44 improves the plant's tolerance to the salinity stress.

The WRKY transcription factors (TFs) are among the most diverse TF families of plants. They are implicated in various processes related to plant growth and stress response. Kenaf (Hibiscus cannabinus L.), an important fiber crop, has many applications, including the phytoremediation of saline-alkaline soil. However, the roles of WRKY TFs in kenaf are rarely studied. In the present study, 46 kenaf WRKY genes were genome-widely identified and characterized by gene structure, phylogeny and expression pattern analysis. Furthermore, the HcWRKY44 gene was functionally characterized in Arabidopsis under salinity and drought stresses. HcWRKY44 is a nuclear-localized protein that is positively induced by salinity and drought, with roots showing maximum accumulation of its transcripts. Under NaCl and abscisic acid (ABA) stress conditions, plants overexpressing HcWRKY44 had higher germination rates, better root growth and increased survival than control plants; however, it did not improve the ability to withstand drought stress. Moreover, ABA signaling genes (ABI1, ABI2, and ABI5), ABA-responsive genes (ABF4, RD29B, COR15A, COR47, and RD22), stress-related genes (STZ, P5CS, and KIN1), and ionic homeostasis-related genes (SOS1, AHA1, AHA2, and HKT1) were positively induced in HcWRKY44 transgenic plants under NaCl treatment. These results suggest that HcWRKY44 improved plant's tolerance to salt stress but not osmotic stress through an ABA-mediated pathway. In summary, this study provides provided comprehensive information about HcWRKY genes and revealed that HcWRKY44 is involved in salinity tolerance and ABA signaling.

Genome-wide identification and expression analysis response to GA3 stresses of WRKY gene family in seed hemp (Cannabis sativa L).

WRKY transcription factor is one of the largest transcription factor families in higher plants. However, the investigations of the WRKY gene family have not yet been reported in seed hemp. In the present study, we identified 39 CasWRKYs at the genome-wide level and analyzed phylogenetic relationship, chromosome location, cis-acting elements, gene structure, conserved motif, and expression pattern. Based on the gene structure and phylogenetic analyses, CasWRKY proteins were divided into 3 groups and 7 subgroups. The gene duplication investigation revealed that 6 and 5 pairs of CasWRKY genes underwent tandem and segmental duplication events, respectively. These events may contribute to the diversity and expansion of the CasWRKY gene family. The regulatory elements in the promoter regions of CasWRKYs contained diverse cis-regulatory elements, among which P-box cis-regulatory elements showed high frequency, indicating that CasWRKYs can respond to the regulation of gibberellin. The expression profiles derived from RNA-seq and qRT-PCR showed that 13 CasWRKY genes could respond to GA3 stress and affect fiber development, as well as play significant roles in stem growth and development. This study will serve as molecular basis and practical reference for further exploring the genetic evolution and biological function of CasWRKY genes in seed hemp.

Comparative transcriptome sequencing analysis and functional identification of a NAM-2-like gene in jute (Corchorus capsularis L.).

Jute (Corchorus capsularis L.) is one of the most important sources of natural fibre. Drought is among the main factors affecting the production of jute. It is essential for drought tolerance improvement to discover the genes associated with jute development during drought stress. In this study, we analyzed the transcriptome of jute under drought stress and identified new genes involved in drought stress response. In total, 120,219 transcripts with an average length of 764 bp were obtained, these transcripts included 94,246 unigenes (average length, 622 bp). Differentially expressed genes (DEGs) were discovered in drought stress (1329), among which 903 genes showed up-regulated expression, while 426 genes showed down-regulated expression. GO enrichment analyses indicated most of the enriched biological pathways were biosynthesis pathways of organic ring compounds and cellular nitrogen compounds. KEGG enrichment analyses indicated 573 DEGs were involved in 157 metabolic pathways. RT-qPCR experiments indicated that the expression trends were consistent with the results of the high-throughput sequencing. Over-expression of no apical meristem (NAM) -2-like gene increased drought tolerance and knockdown plants were drought sensitive. It has expression peaks after 6 h of drought stress and regulate 3-ketoacyl-CoA synthase gene expression. Yeast-2-Hybrid assays validated the physical interaction between NAM-2-like protein and KCS. The results provide relatively comprehensive information regarding genes and metabolic pathways that lays the foundation for the breeding of drought-resistant varieties, and represent the first identification of NAM-2-like gene and provides new insight into the regulatory network of drought tolerance in Corchorus capsularis L.

Overexpression of CcNAC1 gene promotes early flowering and enhances drought tolerance of jute (Corchorus capsularis L.).

Drought is the main factor that significantly affects plant growth and has devastating effects on crop production of jute. NAC (NAM, ATAF, and CUC2) transcription factors (TFs) are a large gene family in plants that have been shown to play many important roles in regulating developmental processes and abiotic stress resistance. In this study, a NAC transcription factor, CcNAC1, was cloned and characterized its function in jute. RT-qPCR analysis showed that CcNAC1 expression peaks after 8 h of drought stress. CcNAC1 overexpression and knockdown plants were created by Agrobacterium-mediated genetic transformation. PCR and southern hybridization results indicate that the CcNAC1 gene was integrated into the genome of jute. Overexpression of the CcNAC1 gene sped up the plant growth, promoted early flowering, and increased drought tolerance compared to the control plants. 3-Ketoacyl-CoA synthase (KCS) gene expression level increased significantly in the CcNAC1-overexpression plants and decreased in knockdown plants, which showed that CcNAC1 transcription factor regulated KCS gene expression. Yeast-2-Hybrid (Y2H) assays validated the physical interaction between CcNAC1 and KCS. The results provide relatively comprehensive information on the molecular mechanisms of CcNAC1 gene underlying the regulation of plant growth and drought stress resistance, and indicate that CcNAC1 acts as a positive regulator in drought tolerance in jute (Corchorus capsularis L.).

Complete Chloroplast Genome Sequence of Hibiscus cannabinus and Comparative Analysis of the Malvaceae Family.

Kenaf (Hibiscus cannabinus) is one of the most fast-growing bast in the world and belongs to the family Malvaceae. However, the systematic classification and chloroplast (cp) genome of kenaf has not been reported to date. In this study, we sequenced the cp genome of kenaf and conducted phylogenetic and comparative analyses in the family of Malvaceae. The sizes of H. cannabinus cp genomes were 162,903 bp in length, containing 113 unique genes (79 protein-coding genes, four rRNA genes, and 30 tRNA genes). Phylogenetic analysis indicated that the cp genome sequence of H. cannabinus has closer relationships with Talipariti hamabo and Abelmoschus esculentus than with Hibiscus syriacus, which disagrees with the taxonomical relationship. Further analysis obtained a new version of the cp genome annotation of H. syriacus and found that the orientation variation of small single copy (SSC) region exists widely in the family of Malvaceae. The highly variable ycf1 and the highly conserved gene rrn32 were identified among the family of Malvaceae. In particular, the explanation for two different SSC orientations in the cp genomes associated with phylogenetic analysis is discussed. These results provide insights into the systematic classification of the Hibiscus genus in the Malvaceae family.

Postoperative Serum Albumin Decrease Independently Predicts Delirium in the Elderly Subjects after Total Joint Arthroplasty.

BACKGROUND: Postoperative delirium (POD), a neurobehavioral syndrome induced by dysfunction of neural activity, is a common and serious complication. This current study aimed to investigate independent predictors for POD in elderly subjects after total joint arthroplasty (TJA). METHODS: Eligible elderly patients (≥65 years) who underwent elective unilateral primary hip or knee arthroplasty under epidural anesthesia from October 2016 to January 2019 were consecutively enrolled. POD was diagnosed following the guidance of the 5th edition of Diagnostic and Statistical Manual of Mental Disorders, (DSM V, 2013). The relative change in serum Alb (ΔAlb) was defined as the absolute value of (preoperative Alb value- nadir value within postoperative day 2)/preoperative Alb ×100%. The predictive value of ΔAlb for POD was evaluated by receiver operating characteristic (ROC) curve analysis. Univariate and multivariate logistic regression analyses were used for evaluating risk factors for POD. RESULTS: A total of 328 patients were enrolled in the analysis, of which 68 (20.7%, 68/328) patients developed POD within postoperative 7 days. ΔAlb was an effective predictor for POD with an area under the curve (AUC) of 0.821, a sensitivity of 76.15% and a specificity of 70.59%, respectively (P<0.001). Univariate and multivariate logistic regression analyses indicated that ΔAlb was the only independent risk factor for POD (OR: 2.43, 95%CI: 1.17-4.86, P=0.015). CONCLUSION: ΔAlb was an independent risk factor for POD in elderly subjects after TJA.

300 kV/6 mA integrated Cockcroft-Walton high voltage power supply for a compact neutron generator.

A high voltage power supply system for a compact neutron generator is developed. A four-stage symmetrical Cockcroft-Walton voltage multiplier circuit is adopted to produce 300 kV direct current high voltage. A two-stage 360 kV isolation transformer system is used to drive the ion source power supply. The high voltage power supply and the isolation transformer system are integrated in an epoxy bucket with a size of ϕ360 × 700 containing No. 25 transformer oil. The maximum output voltage of the power supply can reach 300 kV. The variation in the high voltage power supply is less than 0.5% when the power supply works at 300 kV/6 mA with an input voltage variation of ±8%. Meanwhile, the isolation transformer system can withstand more than 360 kV, with its output power being about 2.5 kW. No overvoltage protection devices are used in the power supply, and the protection resistors are connected in series to two pairs of rectifiers at the highest and lowest potential terminals and to the output terminal of the voltage multiplier to prevent overcurrent.