Genome survey analysis and SSR loci mining of Bupleurum falcatum / 中国中药杂志

Buplewrum falcatum is a traditional Chinese medicine,which is mainly used for the treatment of cold and liver protection. B. falcatum is dominantly cultivated in Japan as well as planted in China,Korea and other countries and regions. In order to determine the appropriate sequencing strategy,the genome survey before large-scale genome sequencing is needed. This survey can provide information about the size and complexity of the whole genome of the target species. In the present study,the next generation sequencing technology( Illumina Hiseq 2000) was used to analyze the genome size and complexity of B. falcatum. In addition,SSR loci were analyzed from the sequenced data. Primer 3 was used to design specific primers and 33 pairs of primers were randomly selected for PCR with template DNA of B. falcatum,and the PCR system and optimal annealing temperature were screened. A total of 288. 64 G genome sequence data was obtained,and the estimated genome size of B. falcatum was 2 119. 58 Mb. The measured genome data depth was138×; the rate of heterozygosity was 1. 84%; and the ratio of repeat sequence was 83. 89%. It is speculated that the genome of B. falcatum is complex. The preliminary assembly was performed with K-mer = 41,and the contig N50 was 224 bp,the total length 896. 97 Mb,the scaffold N50 313 bp,and the total length was 922. 67 Mb. A total of 91 377 SSR sequences were detected in the sequenced genome data which were distributed in 70 809 unigenes.The main type is dinucleotide repeats,with 49 680 sequences,accounting for70. 16%. Among the 33 pairs of primers randomly synthesized according to the obtained SSR sequences,21 pairs were successfully amplifying the target sequences. The results will be helpful for later large scale genome sequencing and SSR molecular markers development for germplasm identification and trait mapping.

Application of CRISPR/Cas9 in plant biology

The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins) system was first identified in bacteria and archaea and can degrade exogenous substrates. It was developed as a gene editing technology in 2013. Over the subsequent years, it has received extensive attention owing to its easy manipulation, high efficiency, and wide application in gene mutation and transcriptional regulation in mammals and plants. The process of CRISPR/Cas is optimized constantly and its application has also expanded dramatically. Therefore, CRISPR/Cas is considered a revolutionary technology in plant biology. Here, we introduce the mechanism of the type II CRISPR/Cas called CRISPR/Cas9, update its recent advances in various applications in plants, and discuss its future prospects to provide an argument for its use in the study of medicinal plants.

Studies on Identification of Bupleurum Cultivated Germplasm Using SSR Molecular Markers / 世界科学技术-中医药现代化

This study was aimed to establish the method of identifying bupleurum cultivated germplasm using simple sequence repeat (SSR) molecular markers and to initially establish dataset of characteristic SSR bands to the bred cultivars or strains. From the bupleurum SSR primer pairs which were designed in previous work, 50 primer pairs were selected. Two bred strains and 4 other bupleurum cultivated germplasms were used as test materials. Primers pairs were screened with effective PCR amplification and high polymorphism. Meanwhile, conditions for PCR amplification and electrophoresis were optimized. Then, obtained SSR bands were analyzed and a clustering tree on the basis of genetic distance was constructed. The results showed that 9 SSR primer pairs can be used for identification. The suitable assay conditions were established and characteristic SSR bands were obtained for tested materials. The tested samples can be divided into 4 categories in the genetic similarity coefficient of 0.73. TheB. scorzonerifolium cultivated inHeilongjiang andChuanhongchaiNo. 1 strains were clustered as one category. ChuanbeichaiNo. 1 strain andZhongchai No. 1 cultivar clustered as another category. Cultivated germplasms fromSichuan Fengshunand Rongxian clustered as a unique category. It was concluded that the primer pairs and assay method established in the present study can be used as reference in identification of bupleurum cultivars or cultivated germplasms.

Expression analyses of BcUGT3 and BcUGT6, and their in vitro expression in Escherichia coli / 中国中药杂志

The tissue-specific and MeJA-induced transcriptional levels of BcUGT3 and BcUGT6 in Bupleurum chinense were analyzed in the present study. The transcriptional levels of BcUGT3 in root, leaf, flower and fruit were similar and they all were higher than those in stem. The transcriptional level of BcUGT6 was the highest in leaf and the lowest in flower among in all tested tissues. With non-treated adventitious roots as control, BcUGT6's transcriptional levels were elevated to nearly 2 folds for 2 h, 8 h, 24 h, 2 d and 4 d in MeJA-treated adventitious roots of B. chinense. It showed that the transcriptional level of BcUGT6 was slightly affected by MeJA. While, BcUGT3's transcriptional levels were gradually elevated, and till 4 d after MeJA treatment, the expression level was about 7 folds than that of non-treated control. Using pET-28a (+), the expressions of two genes was investigated. Induced by IPTG, the target proteins were expressed in E. coli and then purified. All the results obtained in the present study will be helpful for follow-up bio-function analysis of BcUGT3 and BcUGT6.

Induction of hairy roots and plantlet regeneration of Bupleurum chinense DC / 药学学报

In this study, the induction of hairy roots of Bupleurum chinense DC. was explored and established after experiments at different conditions: A. rhizogenes A4 was used to infect the leaves bases of B. chinense tube seedlings. The explants were co-cultured on Phytagel-solidified media for 3 days and then, were turned into solid media, similar with the co-culture media except that bacteriostat was added. After 10 days, rootlets began to appear and after 4 to 5 weeks, rootlets can be converted into liquid shaking culture stage. Plants regeneration from hairy root was useful for the research of new germplasm production and the variety improvement breeding. In the present study, the regenerated plants were obtained. One approach was to continuously culture under light conditions the seedlings which parting off spontaneously from the hairy roots during liquid shaking culture. The other approach was to culture the callus-like tissues produced by hairy roots with the optimized regeneration media for the induction of regenerated plants. The results of present study provide a technique to induce hairy roots and plantlet regeneration of B. chinense and this technique is helpful for the researches on metabolism, especially on the Agrobacterium-mediated genetic transformation of B. chinense.

Expression analysis of glycosyltransferase BcUGT1 from Bupleurum chinense DC. and its expression in E. coli and the target protein purification / 药学学报

The ORF sequence of glycosyltransferase gene BcUGT1 cloned from Bupleurum chinense DC. was analyzed and its three dimentional structure was predicted. Using qRT-PCR method, the expression characteristics of BcUGT1 after methyl jasmonate (MeJA) induction and in different plant tissues were investigated. The results showed that BcUGT1 may be involved in saikosaponin biosynthesis in B. chinense. Thereafter, the recombinant vectors of BcUGT1 were constructed for its expression in E. coli. The target protein was successfully expressed and purified. In the present study, three vectors, pRSET-A, pET-28a (+) and pET-30a (+), and three isolates of E. coli, BL21 (DE3) plysS, BL21A1 and BL21-CodonPlus (DE3)-RIPL were used under different induction conditions, such as different concentrations and during times of inducers (L-arabinose and IPTG) and different inducing temperatures. The results showed that in the condition of 0.5 or 1 mmol x L(-1) IPTG, 16 degrees C, 20 h, target protein expressed in BL21-CodonPlus (DE3)-RIPL with pET-28a (+) or pET-30a (+) as vector. Using PrepEase His-tagged protein purification kit, the target protein was purified. The present work will be helpful for follow-up bio-function analysis of BcUGT1.

Induction of hairy roots and plantlet regeneration of Bupleurum chinense DC / 药学学报

In this study, the induction of hairy roots of Bupleurum chinense DC. was explored and established after experiments at different conditions: A. rhizogenes A4 was used to infect the leaves bases of B. chinense tube seedlings. The explants were co-cultured on Phytagel-solidified media for 3 days and then, were turned into solid media, similar with the co-culture media except that bacteriostat was added. After 10 days, rootlets began to appear and after 4 to 5 weeks, rootlets can be converted into liquid shaking culture stage. Plants regeneration from hairy root was useful for the research of new germplasm production and the variety improvement breeding. In the present study, the regenerated plants were obtained. One approach was to continuously culture under light conditions the seedlings which parting off spontaneously from the hairy roots during liquid shaking culture. The other approach was to culture the callus-like tissues produced by hairy roots with the optimized regeneration media for the induction of regenerated plants. The results of present study provide a technique to induce hairy roots and plantlet regeneration of B. chinense and this technique is helpful for the researches on metabolism, especially on the Agrobacterium-mediated genetic transformation of B. chinense.

Studies on high efficient plant regeneration system from anther callus of Bupleurum chinense / 中国中药杂志

The callus of Bupleurum chinense with anthers at the stage of uninucleate was induced. After several subcultures, anther calli of B. chinense were cultured at 20 MS culture mediums with different plant hormones to differentiate into plantlets. Differentiation of callus was detected after 21 and 49 days to select the most effective medium. There were 19 culture mediums in which anther callus could differentiate into plantlets with differentiation rate range from 3% to 60% , and most less than 20%. MS + KT 0.5 mg x L(-1) + sucrose 30 g c L(-1) + phytagel 5 g x L(-1) was the best differentiation medium with the differentiation rate of 60%, followed by MS + ZT 1.0 mg x L(-1) + sucrose 30 g x L(-1) + phytagel 5 g x L(-1) with the differentiation rate of 58%. Then plantlets were transferred to rooting medium to obtain whole plant. All plantlets could root in the rooting medium of MS + sucrose 30 g x L(-1) + phytagel 5 g x L(-1) and 1/2 MS + NAA 0.5 mg x L(-1) + sucrose 30 g x L(-1) + phytagel of 5 g L(-1) with the rooting rate of 100%. As a result, the high efficient and stable plant regeneration system was established from anther callus of B. chinense.

Isolation and identification of pathogen of seedling blight of Platycodon grandiflorum / 中国中药杂志

<p><b>OBJECTIVE</b>To isolate and identify pathogen of the seedling blight occurred in Platycodon grandiflorum.</p><p><b>METHOD</b>The morphological observation, rDNA ITS sequence analysis, and Koch's postulates were used to identify the isolates of the causal agent.</p><p><b>RESULT</b>The isolates of the causal agent was Rhizoctonia solani.</p><p><b>CONCLUSION</b>The result confirmed that R. solani is the pathogen of seedling blight of P. grandiflorum.</p>

Expression analysis of glycosyltransferase BcUGT1 from Bupleurum chinense DC. and its expression in E. coli and the target protein purification / 药学学报

The ORF sequence of glycosyltransferase gene BcUGT1 cloned from Bupleurum chinense DC. was analyzed and its three dimentional structure was predicted. Using qRT-PCR method, the expression characteristics of BcUGT1 after methyl jasmonate (MeJA) induction and in different plant tissues were investigated. The results showed that BcUGT1 may be involved in saikosaponin biosynthesis in B. chinense. Thereafter, the recombinant vectors of BcUGT1 were constructed for its expression in E. coli. The target protein was successfully expressed and purified. In the present study, three vectors, pRSET-A, pET-28a (+) and pET-30a (+), and three isolates of E. coli, BL21 (DE3) plysS, BL21A1 and BL21-CodonPlus (DE3)-RIPL were used under different induction conditions, such as different concentrations and during times of inducers (L-arabinose and IPTG) and different inducing temperatures. The results showed that in the condition of 0.5 or 1 mmol x L(-1) IPTG, 16 degrees C, 20 h, target protein expressed in BL21-CodonPlus (DE3)-RIPL with pET-28a (+) or pET-30a (+) as vector. Using PrepEase His-tagged protein purification kit, the target protein was purified. The present work will be helpful for follow-up bio-function analysis of BcUGT1.

The mechanical wound transcriptome of three-year-old Aquilaria sinensis / 药学学报

Chinese agarwood is formed in the aromatic resinous wood formed in Aquilaria sinensis (Lour.) Gilg (botanical family: Thymelaeaceae). Only when suffering stress of wound, etc, can A. sinensis produce sesquiterpenes etc. compounds of agarwood around wounds. However, little is known about how wound induced the biosynthesis pathway of sesquiterpenes. To reveal the molecular mechanism of wound-induced agarwood formation, RNA sequencing (RNA-seq) technology was used to investigate the profile of gene expression in A. sinensis treated by mechanical wounding and elucidate its functional gene. A total of 40,295 ESTs with an average read length of 305 bp were generated and 22 095 unigenes were formed by initial gene splicing. 61.6% of these unigenes (13 611) were annotated using BLAST searches against the SwissProt, KEGG, Nr and Nt databases. Twenty-six unigenes (encoding 7 enzymes) were found to be involved in sesquiterpene of agarwood biosynthesis by bioinformatic tools of Gene Ontology and KEGG. Novel genes that are potentially involved in sesquiterpenes biosynthesis were identified in A. sinensis, providing data for further sesquiterpenes biosynthesis pathway by molecular methods and the EST data establish a foundation for future studies in the molecular mechanisms of wound-induce agarwood formation in A. sinensis.

Cloning of UGT gene of Bupleurum chinense and construction of over expressing and RNAi transgenic vectors / 中国中药杂志

<p><b>OBJECTIVE</b>To clone the full-length cDNA of a uridine diphosphate glycosyltransferase (UGT) gene which may be involved in saikosaponin biosynthesis of Bupleurum chinense, and construct the transgenic vectors for over expression and RNAi of the cloned UGT. These works will provide foundation for further its function analysis by transgene study.</p><p><b>METHOD</b>RAGE and LD-PCR were used to clone the full-length cDNA of the UGT, on the basis of its partial cDNA sequence obtained from our previous 454-sequenced dataset. The ORF and partial sequences of the UGT were PCR cloned using primers with corresponding restriction enzymes cutting sites. The PCR products were digested with corresponding restriction enzymes and then were inserted into pCAMBIA-SUPER 1 300 and pHANNIBAL. The recombinant pHANNIBAL were digested with Not I and then were inserted into a binary vector, pART27. Finally, the transgenic vectors for over expression and RNAi of the cloned UGT were constructed.</p><p><b>RESULT</b>The full-length cDNA of a UGT were cloned from B. chinense. The recombinant vectors for over expression and RNAi of the UGT were obtained.</p><p><b>CONCLUSION</b>Our works on full-length cDNA cloning and transgenic vectors construction provide a substantial foundation for follow-up biofunction analysis of the UGT through transgenic research.</p>

Factors Affecting Embryogenic Callus Production and Plant Regeneration in Anther Culture of Bupleurum chinense / 中草药·英文版

Objective To evaluate the influences of the genotypes,anther developmental stages,and cultural conditions on the efficiency of embryogenic callus induction and plant regeneration in the anthers culture of Bupleurum chinense.Methods The different effects such as four genotypes,plant growth regulators,and temperature condition were compared in the experiments.The histological study was performed with the process of the anther culture.Results The highest inducing rate of embryogenic calli were achieved for the genotypes Zhongcaiyihao(ZCYH),Z4,and Z5 at the early-to middle-uninucleate stages,except for genotype ZPM1 at the tetrad stage.Cold pretreatment increased the production of the embryogenic callus,in which 4-day cold pretreatment improved the production of embryogenic callus from 0% to 2.2% and 5.0% for genotypes ZPM1 and ZCYH,respectively.No embryogenic callus was induced in the medium containing less than 0.75 mg/L 2,4-dichlorophenoxyacetic acid(2,4-D).The highest regeneration rate (34.6%)was obtained in 1/2 MS salts regeneration medium supplemented with 0.1 mg/L 6-benzylmaminopurine (BA).The low concentration of BA was able to promote the embryogenic callus formation and subsequent plantlet regeneration via somatic embryogenesis.Chromosome counting of regenerated plantlets showed mostly diploid plant (2n = 12)with only one haploid plant(n = 6).Because of the low rate of microspore embryo formation,we only tracked the process of embryogenesis from the connective tissue,instead of microspore by histological observations.Conclusion This study establishes an efficient system for embryogenic callus induction and plant regeneration system.This is the first report on the haploid plantlet through the anther culture orB.chinense.

Breeding of new varieties "zhongchai no. 2" and "zhongchai no. 3" of Bupleurum chinense / 中国中药杂志

<p><b>OBJECTIVE</b>To breed new varieties with better uniformity and commercial quality as well as higher saikosaponin contents.</p><p><b>METHOD</b>The excellent germplasm resources were selected from "zhongchai no. 1" population. Single plant method was applied to get better varieties. All the breeding material was investigated according to morphological characters, agronomic characters and the contents of saikosaponin a and saikosaponin d. The experiments of comparative test and varieties regional test were carried out.</p><p><b>RESULT</b>The bred new varieties of "zhongchai No. 2" and "zhongchai No. 3" had better uniformity. The dark brown roots ratios of the two varieties were 83.2%, 89.9%, respectively. The contents of saikosaponins (a + d) of the two varieties reached 1.31%, 1.02%, respectively.</p><p><b>CONCLUSION</b>"zhongchai No. 2" and " zhongchai No. 3" both had the advantages of better uniformity, darker brown roots and higher saikosaponin contents.</p>

Construction of genetic linkage map of Bupleurum chinense DC. using ISSR and SSR markers / 药学学报

Molecular genetic map is a fundamental organizational tool for genomic research. However, a genetic linkage map for Bupleurum chinense DC. has not been developed. In this study, with the theory of pseudo-testcross, 96 F1 plants from an intraspecific cross of B. chinense were used as mapping populations. Twenty eight ISSR (inter-simple sequence repeat) primers and 44 SSR (simple sequence repeat) primers were used to detect the polymorphisms between the parental plants, and of them, 28 ISSRs and 14 SSRs were selected to analyze the F1 populations. The map consisted of 13 linkage groups which included 80 (72 ISSRs and 8 SSRs) loci, and covered 2 633.9 cM with an average density of 33.4 cM. All 13 linkage groups consisted of 2-31 loci ranging in length from 15.4-1295.7 cM. This map will provide a basis for studies on gene mapping, map-based cloning and maker-assisted selection of important traits in B. chinense.

Characteristics and abortion cytological pathways of male sterility of Bupleurum chinense / 中国中药杂志

<p><b>OBJECTIVE</b>To study the characteristics of male sterility of Bupleurum chinense and further explore the developmental period and reason of abortion for the male sterile plants.</p><p><b>METHOD</b>The morphological characteristics of B. chinense male sterile and normal plants were investigated and compared. The anther development process and pollen viability of two types of plants were examined by microscopic assay.</p><p><b>RESULT AND CONCLUSION</b>The shapes and sizes of anther and filament were different between the male sterile and the normal plants. For the male sterile plant's, the filament size was no more than 1/2 of that of normal plants and the anthers were shriveled, failed to dehisce and pollinate naturally, and the pollen grains in the anthers had no vitality. Other morphological characteristics were similar between two types of plants. The main reason leading to male sterility of B. chinense was the abnormal development of tapetum cells with two circumstances. The one is that the tapetum cells degraded early during the period of microsporocyte phase to tetrad phase and the other is that the tapetum cells proliferated with delayed degradation in the tetrad to uninucleate phase.</p>

Construction of genetic linkage map of Bupleurum chinense DC. using ISSR and SSR markers / 药学学报

Abstract: Molecular genetic map is a fundamental organizational tool for genomic research. However, a genetic linkage map for Bupleurum chinense DC. has not been developed. In this study, with the theory of pseudo-testcross, 96 F1 plants from an intraspecific cross of B. chinense were used as mapping populations. Twenty eight ISSR (inter-simple sequence repeat) primers and 44 SSR (simple sequence repeat) primers were used to detect the polymorphisms between the parental plants, and of them, 28 ISSRs and 14 SSRs were selected to analyze the F1 populations. The map consisted of 13 linkage groups which included 80 (72 ISSRs and 8 SSRs) loci, and covered 2 633.9 cM with an average density of 33.4 cM. All 13 linkage groups consisted of 2-31 loci ranging in length from 15.4-1295.7 cM. This map will provide a basis for studies on gene mapping, map-based cloning and maker-assisted selection of important traits in B. chinense.