Full-length transcriptome sequence and identification of genes involved in phenylethanol glycoside biosynthesis in Rehmannia glutinosa / 药学学报

italic>Rehmannia glutinosa belongs to the Scrophulariaceae family with important medicinal value. In order to effectively explore the transcriptome information of R. glutinosa and identify the genes encoding enzymes involved in phenylethanol glycoside (PhGs) biosynthesis, the leaves, stems and tuberous roots of R. glutinosa were used for transcriptome sequencing using Pacific Biosiences RS II platform. A total of 27 773 transcripts were generated with an average length of 2 380 bp, and 27 236 coding sequences (CDS) were predicted. Using BLAST software, non-redundant transcript sequences were annotated with NR, NT, GO, COG, KEGG, SwissProt and Interpro databases and a total of 27 399 annotated genes were obtained. Among them, the number of genes related to Sesamum indicum in the NR database was the highest (81.44%), which is consistent with their evolutionary relationship. Enzymes likely involved in the biosynthesis of isoacteoside, echinacoside, cistanosides A, cistanosides F, 2′-acetylacteoside and leonoside F were identified, and 143 genes were identified in R. glutinosa full-length transcriptome. The expression levels of 19 genes correlated with acteoside content in twelve tissues of R. glutinosa, and most showed higher expression levels in leaf tissues and floral organs. This study provides more reliable transcriptome data for screening R. glutinosa for functional genes and provides a foundation for the study of the molecular mechanisms of PhGs biosynthesis.

Identification and biological characteristics of a pathogen causing leaf blight of Rehmannia glutinosa / 中国中药杂志

Leaf blight outbroke in Rehmannia glutinosa plantation in Wenxian county, Henan province in 2019. R. glutinosa plants with diseased leaves were collected from the plantation, and three strains were isolated from the diseased leaf samples. Pathogenicity test, morphological observation, and phylogenetic analysis of ITS, EF1-α, and Tub suggested that they were respectively Fusarium proliferatum, F. oxysporum, and F.acuminatum. Among them, F. acuminatum, as a pathogen of R. glutinosa leaf disease, had never been reported. To clarify the biological characteristics of F. acuminatum, this study tested the influence of light, pH, temperature, medium, carbon source, and nitrogen source on the mycelial growth rate of the pathogen during a 5-day culture period, and explored the lethal temperature. The results showed that the mycelia grew well under the photoperiod of 12 h light/12 h darkness, at 5-40 ℃(optimal temperature: 25 ℃), at pH 4-11(optimal pH: 7.0), on a variety of media(optimal medium: oatmeal agar), and in the presence of diverse carbon and nitrogen sources(optimal carbon source: soluble starch; optimal nitrogen source: sodium nitrate). The lethal temperature was verified to be 51 ℃(10 min). The conclusion is expected to lay a scientific basis for diagnosis and control of R. glutinosa leaf diseases caused by F. acuminatum.

Analysis of Volatile Organic Compounds in Rhizosphere Soil of Rehmannia glutinosa Under Intercropping Zea mays Based on GC-MS Metabonomics / 中国实验方剂学杂志

Objective:To explore the composition characteristics of rhizosphere soil under <italic>Rehmannia glutinosa-Zea mays</italic> intercropping model，and screen out special signal substances in rhizosphere soil of <italic>R. glutinosa</italic> under intercropping <italic>Z. mays</italic>， so as to provide the basis for the study of allelopathic substances in continuous cropping obstacle of <italic>R. glutinosa</italic>. Method:In this experiment，rhizosphere soils of <italic>R. glutinosa</italic> under <italic>Z. mays </italic>intercropping and <italic>R. glutinosa </italic>single cropping models in July，August，September and October were taken as the research objects， and the volatile organic compounds in ethyl acetate fraction were analyzed by gas chromatography-mass spectrometry （GC-MS）. Principal component analysis （PCA）， hierachical cluster analysis （HCA） and orthogonal partial least squares discriminant analysis （OPLS-DA） analysis were performed on the data by SIMCA 14.1 to screen out potential differences in volatile organic compounds between the two models. Result:The types of volatile organic compounds in intercropping and single cropping models were mainly hydrocarbons， alcohols， esters， ketones， amides， acids and other substances. Specifically， the average relative contents of hydrocarbons，esters and amides in intercropping model were 58.46%，32.15% and 5.42% respectively，while the relative contents of hydrocarbons，esters and amides in single cropping model were 37.27%，36.11% and 21.13%. The results of PCA and HCA showed that the characteristics of volatile organic compounds in the ethyl acetate fraction of rhizosphere soil under intercropping and single cropping models could be clearly divided into two categories，the screening results of potential differential components based on OPLS-DA analysis indicated that various components， such as dibutyl phthalate，（<italic>Z</italic>）-9-oleamide，<italic>β</italic>-caryophyllene，dioctyl iso-phthalate， phthalate （2-propylamyl） diester， <italic>n</italic>-hexadecane，octodecane， <italic>n</italic>-heneicosane， were screened from rhizosphere soil under the two models. Conclusion:The <italic>R. glutinosa-Z. mays</italic> intercropping model has certain effects on the volatile organic compounds in the rhizosphere soil of <italic>R. glutinosa</italic>，and the effect of the selected components on the growth and quality characteristics of <italic>R. glutinosa</italic> still need to be further studied.

Effects of density on growth and gene transcription characteristics of Rehmannia glutinosa / 中国中药杂志

The present study analyzed the effects of planting density on the development, quality, and gene transcription characte-ristics of Rehmannia glutinosa using 85-5 and J9 as materials with three planting densities of 5 000, 25 000, and 50 000 plants/Mu(1 Mu≈667 m~2). The agronomic characteristics of leaves and tuberous roots, the content of catalpol and acteoside, and the changes of gene expression were determined. The results showed that the leaf size, the diameter of tuberous root, leaf biomass, tuberous root number, and tuberous root biomass per plant at low density were significantly higher than those of medium and high densities. The content of catalpol and acteoside in leaves was higher at high density. The content of catalpol in tuberous roots was higher at low density, and the change trend was similar to that in leaves, while the content of acteoside in tuberous roots was higher at high density. Transcriptome analysis found that about 1/2 of the expansin genes could change regularly in response to density treatment, which was rela-ted to the development of tuberous roots. The change trend of the gene expression of multiple catalytic enzymes involved in the biosynthesis of catalpol and acteoside was consistent with that of their content, which was presumedly involved in the accumulation and regulation of density-responsive medicinal components. Based on the analysis of the development, medicinal components, and gene expression characteristics of R. glutinosa at different densities, this study is expected to provide an important basis for regulating the quality and yield of medicinal materials of R. glutinosa by managing the planting density.

Identification and expression analysis of NRT1 family genes in Rehmannia glutinosa / 中国中药杂志

NRT1 family proteins play an important roles for absorbing and transporting of nitrate in different plants. In order to identify the NRT1 family genes of Rehmannia glutinosa, this study used 11 NRT1 homologous proteins of Arabidopsis as probe sequences and aligned with the transcriptome data of R. glutinosa by using NCBI BLASTN software. Resulting there were 18 NRT1 proteins were identified in R. glutinosa. On basis of this, a series of the molecular characteristics of R. glutinosa NRT1 proteins including the conserved domains, the transmembrane structure, the subcellular location and phylogenetic features were in detail analyzed. At same time, it were systematically analyzed that the temporal and spatial expression patterns and characteristics of R. glutinosa NRT1 family genes in response to different stress factors. The results indicated that 18 R. glutinosa NRT1 family genes with the length of coding region from 1 260 bp to 1 806 bp, encoded proteins ranging from 419 to 601 amino acids, and all of they owned the domains of typical peptide transporter with 7 to 12 transmembrane domains. These R. glutinosa NRT1 family proteins mostly were found to locate on cellular plasma membrane, and belonged to the hydrophobic proteins. Furthermore, the evolutionary analysis found that the 18 R. glutinosa NRT1 protein family could be divided into two subfamilies, of which 14 NRT1 family genes might occur the positive selection, and 4 genes occur the passivation selection during the evolution process of R. glutinosa. In addition the expression analysis showed that 18 R. glutinosa NRT1 family genes have the distinct expression patterns in different tissues of R. glutinosa, and their expression levels were also obvious difference in response to various stress. These findings infield that 18 R. glutinosa NRT1 family proteins might have obviously different functional roles in nitrate transport of R. glutinosa. In conclusion, this study lays a solid theoretical foundation for clarifying the absorption and transport molecular mechanism of N element during R. glutinosa growth and development, and at same time for deeply studying the molecular function of R. glutinosa NRT1 proteins in absorption and transport of nitrate.

Molecular cloning and expression analysis of iridoid synthase genes from Rehmannia glutinosa / 中国中药杂志

Iridoid synthase( IS),the key enzyme in the natural biosynthesis of vegetal iridoids,catalyzes the irreversible cyclization of 10-oxogeranial to epi-iridodial. In this study,we screened the Rehmannia glutinosa transcriptome data by BLASTn with Catharanthus roseus CrIS cDNA,and found four c DNA fragments with length of 1 527,1 743,1 425,1 718 bp,named RgIS1,RgIS2,RgIS3 and RgIS4,respectively. Bioinformatics analysis revealed that the four iridoid synthase genes encoding proteins with 389-392 amino acid residues,protein molecular weights were between 44. 30-44. 74 k Da,and theoretical isoelectric points were between 5. 30 and 5. 87. Subcellular localization predictions showed that the four iridoid synthase were distributed in the cytoplasm. Structure analysis revealed that R. glutinosa iridoid synthases contain six conserved short-chain dehydrogenase/reductase( SDR) motifs,and their 3 D models were composed typical dinucleotide-binding " Rossmann" folds covered by helical C-terminal extensions. Using the amino acid sequences of four R. glutinosa iridoid synthases,phylogenetic analysis was performed,the result indicated that RgIS3,CrIS and Olea europaea OeIS were grouped together,the other R. glutinosa iridoid synthases and fifteen proteins in other plants had close relationship. Real-time fluorescent quantitative PCR revealed that RgIS1 and RgIS3 highly expressed in unfold leaves,however,RgIS2 and RgIS4 highly expressed in stems and tuberous roots,respectively. RgIS3 showed higher expression levels in non-radial striations( nRS) of the two cultivars,and RgIS1 and RgIS2 had higher expression levels in nRS of QH,while RgIS4 had less expression levels in nRS of QH1. RgIS1,RgIS2 and RgIS3 were up-regulated by Me JA treatment,although the time and degree of response differed. Our findings are helpful to reveal molecular function of R. glutinosa iridoid synthases and provide a clue for studing the molecular mechanism of iridoid biosynthesis.

Phenotypic Character and HPLC Fingerprints of Radial Striations from Different Germplasms Rehmanniae Radix / 中国实验方剂学杂志

Objective: To discuss the phenotypic character and the HPLC fingerprints of radial striations from different germplasms Rehmanniae Radix. Method: The changes in the shape and column diameter of the radial striations of Rehmanniae Radix were observed and measured in the whole growth period. Besides,the HPLC fingerprints of the root,radial and un-radial striations were established to sign the chemical quality and analyzed by principal component analysis(PCA)and systematic cluster analysis. Result: There were significantly differences and regularities in the shape and proportion of the radial striations of different germplasms Rehmanniae Radix. The fingerprints showed the consistency between different types of chemical ingredients,and the differences in chemical quality characteristics mainly lay in the content of chemical compositions and theirs relative ratio. The results of PCA indicated that active ingredients, such as acteoside,catalpol,rehmaionoside D,rehmaionoside A and leonuride, were involved in the quality expression of different parts from various germplasms of Rehmanniae Radix,but each ingredient had a distinctive contribution rate to the differential quality expression between different parts from various germplasms of Rehmanniae Radix. However,the other components involved in the differential quality expression had different contribution rates in different germplasms.The systematic cluster analysis indicated that great differences in the chemical quality between the radial striations and un-radial striations of Beijing-1,Qinhuai,Qinhuai Zheng and 1706 germplasms,but with small differences in 85-5 and Baixuan germplasms. Conclusion: There are differences in phenotypic character of the radial striations and HPLC fingerprints between different germplasms Rehmanniae Radix.

Effects of shading on tuberous root traits, photosynthetic characteristics and gene transcription of Rehmannia glutinosa / 中草药

To reveal the effects of shading on tuberous root and photosynthetic characteristics of Rehmannia glutinosa, and analyze the molecular mechanism of shading affecting the expansion of R. glutinosa tuberous root by transcriptome sequencing. Methods: R. glutinosa plants were treated with full light, 60% shading and 90% shading. High-throughput sequencing was used to sequence the transcriptome of the R. glutinosa tuberous roots treated with full-light and 90% shading, and the differentially expressed genes were screened out. The expression characteristics of some genes in tuberous roots and leaves were analyzed by real-time fluorescence quantitative PCR. Results: After shading, the number of parenchyma cell layers in the tuberous roots was decreased, but the proportion of ducts was increased, the length, diameter and fresh weight of tuberous roots were decreased significantly, and the tuberous roots barely expanded under 90% shading treatment. The number of parenchyma cell was decreased and the proportion of duct was increased in root tubers of R. glutinosa. With the increase of shading degree, the content of chlorophyll a and b and total chlorophyll content were gradually decreased, and photosynthetic capacity was decreased. A total of 3 348 differentially expressed genes were obtained by transcriptome analysis, of which 1 396 were down-regulated and 1 952 were up-regulated. Through enrichment analysis of KEGG metabolic pathway, 1 668 differentially expressed genes (53.4%) were enriched into 117 metabolic pathways, and 17 of them were significantly enriched pathways. The plant hormone signaling pathway was enriched firstly, followed by the plant pathogen interaction pathway, the phenylethanoid glycoside biosynthesis pathway, starch and sucrose metabolic pathways were also enriched significantly. In the hormone signaling pathway, most of different expressed genes were up-regulated. Eleven expansin genes were down-regulated under 90% shading, only five expansin genes were up-regulated. Two of beta-amylase genes (Bmy) related to starch degradation were up-regulated when shading treated, while the sucrose phosphate synthase genes (SPS) were down-regulated. Most of the genes involved in lignin synthesis were down-regulated and most of the genes involved in cellulose synthesis were up-regulated. Conclusion: The photosynthetic capacity of R. glutinosa was decreased under shading conditions, and led to the accumulation of photosynthate decreased in its leaf and tuberous root. R. glutinosa plant responded to shading by regulating the differential expression of a series of hormone pathway genes, which prevent the expansion of tuberous roots.

Progress on germplasm enhancement and breeding of Rehmannia glutinosa / 中国中药杂志

The history of Rehmannia glutinosa breeding has already beyond 100 years. There are rich cultivated varieties and wild germplasm resources in R. glutinosa. However, there also exist a lot of problems, such as, the pedigree of the existing varieties is not clear, the genetic basis is narrow, backward method of germplasm enhancement and breeding. Breeding of new varieties has been unable to meet the demand of R. glutinosa production in the new era. This paper summarizes the species of Rehmannia and their distribution, the diversity of plant morphology and the quality of R. glutinosa germplasm resources, as well as the progress of R. glutinosa breeding in recent 100 years. For ensuring the orderly, effective and safe production of R. glutinosa, the authors suggest to establish the wild resources protection area and germplasm resources garden, deeply study the genetic base of quality, strengthen application of new breeding method such as mutation breeding, haploid breeding and gene editing.

Comparison of chemical quality characteristics between radial striations and non-radial striations in tuberous root of Rehmannia glutinosa / 中国中药杂志

An HPLC method was established to determine the contents of catalpol, acteoside, rehmaionoside A, rehmaionoside D, leonuride in three part of Rehmanni glutinosa in Beijing No.1 variety R. glutinosa during the growth period, This method, in combination with its HPLC fingerprint was used to evaluate its overall quality characteristics.The results showed that：① the content of main components of R. glutinosa varied in different growth stages ;② there was a great difference of the content of main components between theradial striations and the non-radial striations; ③ the two sections almost have the same content distribution of catalpol, acteoside and rehmaionoside D; ④the content of rehmaionoside A in non-radial striations was higher than that in radial striations,while the content of leonuride in radial striations was higher than that in non-radial striations.; ⑤the HPLC fingerprint of radial striations, non-radial striations and whole root tuber were basically identical, except for the big difference in the content of chemical components. The result of clustering displayed that the radial striations, non-radial striations, and whole root were divided into two groups. In conclusion, there was a significant difference in the quality characteristics of radial striations and non-radial striations of R. glutinosa. This research provides a reference for quality evaluation and geoherbalism of R. glutinosa.

A consideration on screening of allelochemicals by using "knock-out/in" of targeting ingredients based on identification model of medicinal effect / 中国中药杂志

This paper clarified in detail the definition, characteristics of allelopathy and its association with consecutive monoculture problem.Most of studies have indicated that it is critical to parse the formation mechanisms of consecutive monoculture problem that identification of allelochemicals and verification of its function. Here, we proposed a new approach to separate and identify the allelochemical group precisely and effectively, in which the "knock-out/in" methods of targeting ingredients in the model of medicinal effect identification and quality control were applied. This method will contribute to deep understanding plant allelopathy, and provide theoretical basis and technical support for alleviating consecutive monoculture problems simultaneously.

Research progress of relationship between continuous cropping obstacles and microRNAs in Rehmannia glutinosa / 中国中药杂志

The efficacy of Rehmannia glutinosa which as a large quantity of traditional Chinese medicine is significant. However, the land must be given up after one season of R. glutinosa cultivation or replanted after a period of 8-10 years because of the severe continuous cropping obstacles. MicroRNAs is a class of endogenous non-coding small RNAs, which participate in regulation of physiological activities by target mRNA cleavage or translational repression in plants. In recent years,studies on the role of miRNAs in plants have made significant progresses,especially in medicinal plants．MiRNAs from some different medicinal plant species have been identified with regulatory effects．When plants are exposed to environmental stress, miRNAs act on stress-related genes and initiate stress-resistance mechanisms in the body against adverse factors. R. glutinosa is also a kind of environmental stress. It is conducive to deciphering the molecular mechanism of continuous cropping obstacles for us by researching miRNAs. This article reviews the production of miRNAs, mechanism, research approaches and characteristics of resisting the environmental stresses in plants, the development trends and future prospect of R. glutinosa miRNAs research.

Advances on molecular mechanisms of Rehmannia glutinosa consecutive monoculture problem formation in multi-omics era / 中国中药杂志

Although consecutive monoculture problems have been studied for many years, no effective treatments are currently available. The complexity of systems triggered the formation of consecutive monoculture problems was one major cause. This paper elaborated the physiological and ecological mechanisms of consecutive monoculture problem formation based on the interaction relationship among multiple factors presented in the rhizosphere soil of consecutive monoculture plants. At same time, in this paper the multiple interactions among cultivated medicinal plants, autotoxic allelochemicals and rhizosphere microbial were proposed to be most important causes that derived the formation of consecutive monoculture problem. The paper also highlighted the advantage of 'omics' technologies integrating plant functional genomics and metabolomics as well as microbial macro-omics in understanding the multiple factor interaction under a particular ecological environment. Additionally, taking R. glutinosa as an example, the paper reviewed the molecular mechanism for the formation of R. glutinosa consecutive monoculture problem from the perspective of the accumulation of allelopathic autotoxins, the rhizosphere microecology catastrophe and theresponding of consecutive monoculture plants. Simultaneously, the roles of mutilple 'omics' technologies in comprehending these formation mechanism were described in detail. This paper provides finally a new insight to solve systematically the mechanism of consecutive monoculture problem formation on molecular level.

Cloning and expression analysis of a tyrosine decarboxylase gene from Rehmannia glutinosa / 中国中药杂志

Tyrosine decarboxylase (TyrDC) is an important enzyme in the secondary metabolism of several plant species, and was hypothesized to play a key role in the biosynthesis of phenylethanoid glycosides. Based on the transcriptome data, we cloned the full-length cDNA (GenBank accession NO. KU640395) of RgTyDC gene from Rehmannia glutinosa, and then performed bioinformatic analysis of the sequence. Further, we detected the expression pattern in different organs and hair roots treated with four elicitors by qRT-PCR. The results showed that the full length of RgTyDC cDNA was 1 530 bp encoding 509 amino acids. The molecular weight of the putative RgTyDC protein was about 56.6 kDa and the theoretical isoelectric point was 6.25. The RgTyDC indicated the highest homology with Sesamum indicum SiTyDC and Erythranthe guttata EgTyDC, both of them were reached 88%. RgTyDC highly expressed in R. glutinosa leaf, especially in senescing leaf, and rarely expressed in tuberous root. After the treatment of SA and MeJA, the relative expression level of RgTyDC mRNA was substantially increased. The results provide a foundation for exploring the molecular function of RgTyDC involved in phenylethanoid glycosides biosynthesis.

Cloning and expression analysis of the expansin gene RgEXPA10 in Rehmannia glutinosa / 药学学报

Using cDNA from Rehmannia glutinosa leaf as template, a 972 bp fragment of expansin gene which containing a 762 bp ORF that encoded 253 amino acids, was cloned, named RgEXPA10, which GenBank accession number for this gene is KF011918. A 1 207 bp genomic sequence of RgEXPA10 was amplified by PCR with leaf DNA as template, sequencing analysis revealed that three exons and two introns in RgEXPA10 genomic sequence, and which GenBank accession number is KF011919. Molecular and bioinformatic analyses indicated that RgEXPA10 protein have DPBB_1 and Pollen_allerg_1 domain, also including a 26 aa nuclear localization signal and a 19 aa transmembrane region. Phylogenetic analysis revealed that RgEXPA10 showed the highest homology with AtEXPA8 among the 26 α-expansins in Arabidopsis thaliana. However, the RgEXPA10 indicated the highest homology with the expansin from Solanum lycopersicum among 22 plant species. Expression patterns using qRT-PCR analysis showed that RgEXPA10 mainly expressed in unfolded leaf, followed by the tuberous root at stage of expanding period, and rarely expressed in senescing leaf. And RgEXPA10 showed higher expression level in tuberous root at 60 and 90 days after emergence. The transcription level of RgEXPA10 significantly reduced under all the three stresses including continuous cropping conditions, salinity and waterlogging. This study will lay foundations for molecular function in development and regulation of different stresses for R. glutinosa.

Isolation and expression analysis of RgMed6 from Rehmannia glutinosa / 中草药

Objective: To clone RgMed6 gene, which coded a subunit of mediator complex, from Rehmannia glutinosa, and to analyze the characteristics of protein sequence and gene expression. Methods: The transcriptional EST database of R. glutinosa was used to search analogs of AtMed6 gene by BLAST, the full-length open reading frame (ORF) of RgMed6 was obtained by assembling the ESTs. BLASTp, the online analysis tool of NCBI was used to get the homologous sequences of RgMed6, and MAFFT has been performed to analyze the multiple sequence alignment. Phylogenetic tree has been constructed using MEGA 6.0 software. Quantitative RT-PCR has been applied to detecting the transcription level of RgMed6 in five tissues as well as in tuberous roots or leaves under three stresses. Results: The cDNA sequence of RgMed6 containing 924 bp was obtained. The ORF of RgMed6 was 771 bp encoding 256 amino acids, which had typical structural domains and a potential nuclear localization signal (NLS). RgMed6 showed the highest expression level in leaves, followed by buds, but very weak in stems. The transcription level of RgMed6 mRNA was reduced under continuous cropping conditions in tuberous roots while it increased under salinity stress in leaves. Conclusion: RgMed6, a mediator subunit gene from R. glutinosa has been obtained for the first time, which can lay the foundation for further studies about its molecular function in development and responses to stress.

Observation of prime position and driving zones in process of tuberous root expanding and expression analysis of phytohormone relative genes in Rehmannia glutinosa / 中国中药杂志

In order to study the development characteristics of Rehmannia glutinosa tuberous root expansion and reveal the regulation mechanism of the genes related to hormones in this process, R. glutinosa "wen-85" was used as the experimental material in this study. R. glutinosa tuberous roots of different developmental stages were collected to observe phenotype and tissue morphology using resin semi-thin sections method. The genes related to hormone biosynthesis and response were chosen from the transcriptome of R. glutinosa, which was previously constructed by our laboratory, their expression levels at different development stages were measured by real-time quantitative PCR. The results showed that the root development could be divided into six stages: seeding, elongation, pre-expanding, mid-expanding, late-expanding and maturity stage. The anatomic characteristics indicated that the fission of secondary cambium initiated the tuberous root expansion, and the continuous and rapid division of secondary cambium and accessory cambium kept the sustained and rapid expansion of tuberous root. In addition, a large number oleoplasts were observed in root on the semi-thin and ultra-thin section. The quantitative analysis suggested that the genes related to biosynthesis and response of the IAA, CK, ABA,ethylene, JA and EB were up-regulated expressed, meanwhile, GA synthesis and response genes were down-regulated expressed and the genes of GA negative regulation factors were up-regulated expressed. The maximum levels of most genes expression occurred in the elongation and pre-expansion stage, indicating these two stages were the key periods to the formation and development of tuberous roots. Oleoplasts might be the essential cytological basis for the formation and storage of the unique medicinal components in R. glutinosa. The results of the study are helpful for explanation of development and the molecular regulation mechanism of the tuberous root in R. glutinosa.

Studies on genetic transformation of Rehmannia glutinosa mediated by Agrobacterium tumefaciens / 中草药

Objective: To determine the optimal concentration of hormone and hygromycin for seedling regeneration of Rehmannia glutinosa. Methods: Using the young leaf of sterile plantlet from R. glutinosa as explants, we conducted the transformation mediated by Agrobacterium tumefaciens, analyzed the efficiency of hygromycin and acetosyringone (AS) on resistant callus induction and plant regeneration. Results: The concentration of hygromycin had greatly affected the production of resistant callus and seedlings. The critical concentration of hygromycin on the resistant callus induction and shoot regeneration were 9 and 6 mg/L, respectively. The optimal concentration of hygromycin for the genetic transformation of Wen 85-5 was 12 mg/L. Adding 100 μmol/L AS could greatly improve the transformation efficiency of R. glutinosa. It was confirmed by PCR detection of hpt gene and GUS staining that the foreign gene was integrated into the genome of R. glutinosa. Conclusion: The stable genetic transformation system of R. glutinosa is established, which lays the foundations for the research on molecular pharmacognosy and genetic improvement.

Numerical analysis of morphological variation of germplasm resources of dioscorea / 中国中药杂志

<p><b>OBJECTIVE</b>Botanical characters of germplasm resources of Dioscorea were observed and compared, which could to offer reference for its genetic improvement, germplasm resource identification and classification.</p><p><b>METHOD</b>Based on field cultivation, twenty-four morphological traits of ninety-four Dioscorea germplasm resources were observed or determined. And the morphological differences among germplasm resources were compared by principal component analysis and cluster analysis.</p><p><b>RESULT</b>There were ample morphological diversity in the twenty-four traits, in especially in leaf size and tuber characters of the ninety-four Dioscorea germplasm resources. The first seven principal components which accounted for 80. 957% of total variance were extracted from the principal component analysis. The ninety-four germplasm resources could be divided into four clusters, which belonging to Dioscorea opposite, D. persimili, D. fordii and D. alata respectively.</p><p><b>CONCLUSION</b>There were large morphological variation among germplasm resources on Dioscorea. Identification of germplasm resources of Dioscorea should focus on leaf size and tuber characters.</p>

Molecular cloning and expression analysis of an Aux/IAA gene (RgIAA1) from Rehmannia glutinosa / 中国中药杂志

To clone and analyze a member of the Auxin/indole-3-acetic acid (Aux/IAA) gene family, RgIAA1, from Rehmannia glutinosa. The transcriptional EST database of R. glutinosa was used to clone the new Aux/IAA gene by cDNA probe of AtIAA14. Bioinformatics was applied to analyze the sequence characteristics of RgIAA1 protein and construct phylogenetiC trees. Quantitative RT-PCR has been applied to detect the transcription level of RgIAA1 in seven tissues as well as in leaves under three stresses. The results showed that, the cDNA sequence of RgIAA1 contains 903 bp was obtained. The open reading frame (ORF) of RgIAA1 was 681 bp encoding 226 amino acids, which has typical structural domains and characteristic sequence of Aux/IAA family proteins. RgIAA1 showed the highest expression level in unfolded leaf, followed by the stem. And the expression of RglAA1 was quickly decreased with leaf growing up. The transcription level increased under continuous cropping conditions while it reduced both in salinity and waterlogging stresses. RgIAA1, an Aux/IAA gene from R. glutinosa has been obtained for the first time, which can lay the foundation for further studies about its molecular function in development and responses to stress.