Screening and characterization of endophytic fungi of Panax ginseng Meyer for biocontrol activity against ginseng pathogens

Forty endophytic fungi isolated from ginseng plants were screened to identify metabolites that had antifungal activity against ginseng microbial pathogens. The metabolites from the fungi were extracted from the liquid culture filtrates using ethyl acetate and then evaluated in vitro for antimicrobial activity against ginseng pathogens (Alternaria panax, Botrytis cinerea, Colletotrichum panacicola, Cylindrocarpon destructans, Rhizoctonia solani, and Phytophthora cactorum). Six of the fungi (Colletotrichum pisi, Fusarium oxysporum, Fusarium solani, Phoma terrestris, unknown 1 and 2) showed effective antimicrobial activity against all or some of the ginseng pathogens, with the extract of P. terrestris showing the strongest antimicrobial activity. The extract also showed inhibitory activity against spore germination of the pathogens. Gas chromatography–mass spectrometry (GC–MS) analysis of P. terrestris extract revealed that forty-one compounds were present in metabolites containing mainly N-amino-3-hydroxy-6-methoxyphthalimide (32% of the total metabolites) and 5H-dibenz [B, F] azepine (7%). Treatment with P. terrestris extract also caused morphological changes and reduced expression of the genes involved in mycelial growth and virulence. Treatment also induced defense-related genes in detached Arabidopsis leaves that were inoculated with the pathogens. These results indicate the antimicrobial potential for use of metabolites extracted from the ginseng endophytic fungi as alternatives to chemicals for biocontrol.     

Proteomic analysis of Korean ginseng (Panax ginseng C.A. Meyer)

Although many reports have been published regarding the pharmacological effects of ginseng, little is known about the biochemical pathways operant in ginsenoside biosynthesis, or the genes involved therein. Proteomics analysis is an approach to elucidate the physiological characteristics and biosynthetic pathways of ginsenosides, main components of ginseng. In this review, we introduced the recent progress in proteomics studies of ginseng (Panax ginseng C.A. Meyer). We briefly reference the genomic analyses of P. ginseng, without which proteomics approaches would have been impossible. Functional genomics studies regarding secondary metabolism in P. ginseng are also introduced here, in order to introduce possible future prospects for further study.     

Extensive characterization of peptides from Panax ginseng C. A. Meyer using mass spectrometric approach

Panax ginseng is an important herb that has clear effects on the treatment of diverse diseases. Until now, the natural peptide constitution of this herb remains unclear. Here, we conduct an extensive characterization of Ginseng peptidome using MS‐based data mining and sequencing. The screen on the charge states of precursor ions indicated that Ginseng is a peptide‐rich herb in comparison of a number of commonly used herbs. The Ginseng peptides were then extracted and submitted to nano‐LC‐MS/MS analysis using different fragmentation modes, including CID, high‐energy collisional dissociation, and electron transfer dissociation. Further database search and de novo sequencing allowed the identification of total 308 peptides, some of which might have important biological activities. This study illustrates the abundance and sequences of endogenous Ginseng peptides, thus providing the information of more candidates for the screening of active compounds for future biological research and drug discovery studies.     

Cytological analysis of ginseng carpel development

Panax ginseng Meyer, commonly known as ginseng, is considered one of the most important herbs with pharmaceutical values due to the presence of ginsenosides and is cultivated for its highly valued root for medicinal purposes. Recently, it has been recognized that ginseng fruit contains high contents of triterpene such as ginsenoside Re as pharmaceutical compounds. However, it is unclear how carpel, the female reproductive tissue of flowers, is formed during the three-year-old growth before fruit is formed in ginseng plants. Here, we report P. ginseng carpel development at the cytological level, starting from the initial stage of ovule development to seed development. The carpel of P. ginseng is composed of two free stigmas, two free styles, and one epigynous bilocular ovary containing one ovule in each locule. Based on our cytological study, we propose that the female reproductive development in P. ginseng can be classified into seven stages: early phase of ovule development, megasporogenesis, megagametogenesis, pre-fertilization, fertilization, post-fertilization, and seed development. We also describe the correlation of the female and male gametophyte development and compare morphological differences in carpel development between ginseng and other higher plants. One unique feature for ginseng seed development is that it takes 40 days for the embryo to develop to the early torpedo stage and that the embryo is small relative to the seed size, which could be a feature of taxonomic importance. This study will provide an integral tool for the study of the reproductive development and breeding of P. ginseng.     

RG-II from Panax ginseng C.A. Meyer suppresses asthmatic reaction

In asthma, T helper 2 (T(H)2)-type cytokines such as interleukin (IL)-4, IL-5, and IL-13 are produced by activated CD4(+) T cells. Dendritic cells played an important role in determining the fate of naive T cells into either T(H)1 or T(H)2 cells. We determined whether RG-II regulates the T(H)1/T(H)2 immune response by using an ovalbumin-induced murine model of asthma. RG-II reduced IL-4 production but increased interferon- gamma production, and inhibited GATA-3 gene expression. RG-II also inhibited asthmatic reactions including an increase in the number of eosinophils in bronchoalveolar lavage fluid, an increase in inflammatory cell infiltration in lung tissues, airway luminal narrowing, and airway hyperresponsiveness. This study provides evidence that RG-II plays a critical role in ameliorating the pathogenic process of asthmatic inflammation in mice. These findings provide new insights into the immunotherapeutic role of RG-II in terms of its effects in a murine model of asthma.     

Plant regeneration through somatic embryogenesis in root-derived callus of ginseng (Panax ginseng C. A. Meyer)

Summary Callus culture was initiated from expiants of mature root tissues of ginseng (Panax ginseng C.A. Meyer) on MS medium enriched with 2,4-D. The ageing callus produced numerous embryoids in this medium. Reculture of these embryoids in media (1/2 MS or B5) supplemented with benzyladenine and gibberellic acid resulted in profuse plantlet regeneration.     

Cytological analysis and genetic control of rice anther development

Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations.Rice (Oryza sativa) is the world's major staple food,and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield.Towards a better understanding of the mechanisms controlling rice male reproductive development,we describe here the cytological changes of anther development through 14 stages,including cell division,differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis.Furthermore,we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana.Additionally,we describe the key genes identified to date critical for rice anther development and pollen formation.     

人参EST资源的SSR信息分析

从7055条人参EST序列中搜索出791个SSR,其出现频率为11．21％,平均长度为21．37bp,平均分布频率为1／5．7kb。二核苷酸重复是主要的重复类型,占全部EST-SSR的56．89％,其次是三核苷酸重复的占全部SSR的21．11％。AT、GAA是二核苷酸和三核苷酸中出现次数最多的重复基元类型,分别占28．89％和10．18％。     

A plant-transformation-competent BIBAC library of ginseng (Panax ginseng C. A. Meyer) for functional genomics research and characterization of genes involved in ginsenoside biosynthesis

Ginseng (Panax ginseng C. A. Mey.) is widely used as a major medicinal herb and as a feedstock for the medicine, beverage, food, cosmetic, etc. industries, in China and several other Asian countries. However, limited research has been accomplished into its genetics, genomics and breeding. To clone, characterize and utilize the genes of economic importance in the species, we have developed a large-insert plant-transformation-competent binary bacterial artificial chromosome (BIBAC) library for Jilin ginseng cv. Damaya. The library contains 141,312 clones, with an average insert size of 110 kb, each likely containing approximately 20–30 genes. The clones of the library have all been arrayed in 384-well microplates and permanently archived. We screened the library and identified BIBAC clones containing nine genes likely involved in the biosynthesis pathway of ginsenosides—the major medicinally effective compounds of ginseng—with approximately four BIBACs per gene. This result further verified the quality of the library and demonstrated its utility in cloning, characterization and utilization of economically important genes in ginseng. Furthermore, since the library is cloned in a plant-transformation-competent BIBAC vector (pCLD04541) that can be directly transformed in a variety of plants via both the Agrobacterium-mediated method and the particle bombardment method, we have also demonstrated the stability of large-insert ginseng DNA BIBACs in different Agrobacterium strains, which is crucial to large-insert BIBAC transformation in plants. Therefore, the Jilin ginseng BIBAC library provides resources and tools useful for functional genomics research, and cloning, characterization and utilization of economically important genes in the species.     

Histological characterization of in vitro regenerated structures of Panax ginseng

Callus was induced from mature leaf lamina, petiole, stem, and main and branch root of Panax ginseng and maintained under different nutrient and light conditions. Heterogenous callus cultures differentiated organoids and/or embryoids. Embryoids that arose from callus cultures of leaf origin germinated into shoots. The occurrence of the early stages of different regenerated structures was proved on histological level.     

CAPS markers using mitochondrial consensus primers for molecular identification of Panax species and Korean ginseng cultivars (Panax ginseng C. A. Meyer)

Cleaved amplified polymorphic sequence (CAPS) marker system using mitochondrial consensus primers was applied for molecular identification of Korean ginseng cultivars (Panax ginseng). Initially, a total of 34 primers were tested to six Korean ginseng cultivars and two foreign Panax species, P. quinquefolius and P. notoginseng. In the polymerase chain reaction (PCR) amplification results, four primers (mt7, mt11, mt13, and mt18) generated co-dominant polymorphic banding patterns discriminating the Korean ginseng cultivars from P. quinquefolius and P. notoginseng. In the CAPS analysis results, the majority of the cleaved PCR products also yielded additional latent polymorphisms between the Korean ginseng cultivars and two foreign Panax species. Specific latent CAPS polymorphisms for cultivar Gopoong and Chunpoong were detected from internal region amplified with mt9 primer by treating HinfI and Tsp509I endonucleases, respectively. Sequencing analysis revealed that the length of amplified region of Korean ginseng cultivars was 2,179 bp, and those of P. quinquefolius and P. notoginseng were 2,178 and 2,185 bp, respectively. Blast search revealed that the amplified region was a mitochondrial cytochrome oxidase subunit 2 (cox2) gene intron II region. Nineteen single nucleotide polymorphisms (SNP) including each specific SNP for Gopoong and Chunpoong, and three insertion and deletion (InDel) polymorphisms were detected by sequence alignment. The CAPS markers developed in this study, which are specific to Gopoong and Chunpoong, and between the Korean ginseng cultivars and two foreign Panax species, will serve as a practical and reliable tool for their identification, purity maintenance, and selection of candidate lines and cultivars.     

Molecular characterization of 5-chlorophyll a/b-binding protein genes from Panax ginseng Meyer and their expression analysis during abiotic stresses

The chlorophyll _a/b-binding protein (CAB) serves in both photosystems (PS), I and II, as a coordinator of antenna pigments in the light-harvesting complex (LHC). The CABs constitute abundant and important proteins in the thylakoid membrane of higher plants. In our study, five CAB genes, which contained full-length cDNA sequences from the 4-year-old ginseng leaves (Panax ginseng Meyer), were isolated and named PgCAB. Phylogenetic comparison of the members of the subfamily between ginseng and higher plants, including Arabidopsis, revealed that the putative functions of these ginseng CAB proteins were clustered into the different family of Arabidopsis CABs; two PgCABs in LHCII family and three PgCABs in LHCI family. The expression analysis of PgCABs consistently showed dark-dependent inhibition in leaves. Expression analysis during abiotic stress identified that PgCAB genes responded to heavy metal, salinity, chilling, and UV stresses differently, suggesting their specific function during photosynthesis. This is the first comprehensive study of the CAB gene family in P. ginseng.     

A specific role for spermidine in the initiation phase of somatic embryogenesis in Panax ginseng CA Meyer

Somatic embryogenesis of Panax ginseng CA Meyer was initiated from suspension aggregates of an embryogenic callus, in a liquid medium consisting of half strength Murashige and Skoog (1962) supplemented with the synthetic auxin benzoselenienyl-3 acetic acid. The addition of spermidine to this initiation medium significantly increased the production of somatic embryos. In this case, the total polyamine content of the embryogenic mass was higher than that of cultures without spermidine. At day 6 of the culture, a transient accumulation of free polyamines, mainly spermidine, was observed. After this peak, free and conjugated polyamines levels did not show significant variation nor did the polyamine oxidase activity. The results clearly demonstrated that spermidine supplied to the medium was oxidised by polyamine oxidase and partially metabolised into putrescine. The role of spermidine and its interaction with auxin in the initiation of the embryogenic process in Panax ginseng are discussed in relation to embryogenic potential.     

Proteome of Oriental ginseng Panax ginseng C. A. Meyer and the potential to use it as an identification tool

Oriental ginseng (Panax ginseng C. A. Meyer) and American ginseng (Panax quinquefolius) are two widely used valuable traditional Chinese medicines (TCM). Previously, the identification of ginseng was mainly performed by analyzing the ginsengnosides using high performance liquid chromatography and amplification of polymorphic DNA using polymerase chain reaction. However, these methods cannot be used to distinguish TCM samples which are from different parts (main root, lateral roots, rhizome head and skin) of ginseng and ginseng culture cells from wild-grown ginseng. The present study aimed to identify different species of ginseng, different parts of the same ginseng and cultured cells of ginseng using a proteomic approach. Two-dimensional electrophoresis (2-DE) maps were established from the American ginseng main root, different parts (main root, lateral roots, rhizome head and skins) of Oriental ginseng and Oriental ginseng culture cells. Our results show that the 2-DE maps of different ginseng samples contain sufficient differences to permit easy discrimination. We have also identified common and specific protein spots in the 2-DE maps of different ginseng samples. The use of these "marker proteins" may help to speed up the identification process.     

Isolation and characterization of repetitive DNA sequences from Panax ginseng

Repetitive sequences constitute a significant component of most eukaryotic genomes, and the isolation and characterization of repetitive DNA sequences provide an insight into the organization and evolution of the genome of interest. We report the isolation and characterization of the major classes of repetitive sequences from the genome of Panax ginseng. The isolation of repetitive DNA from P. ginseng was achieved by the reannealing of chemically hydrolyzed (200 bp-1 kb fragments) and heat-denatured genomic DNA to low C(o)t value. The low C(o)t fraction was cloned, and fifty-five P. ginseng clones were identified that contained repetitive sequences. Sequence analysis revealed that the fraction includes repetitive telomeric sequences, species-specific satellite sequences, chloroplast DNA fragments and sequences that are homologous to retrotransposons. Two of the retrotransposon-like sequences are homologous to Ty1/ copia-type retroelements of Zea mays, and six cloned sequences are homologous to various regions of the del retrotransposon of Lilium henryi. The del retrotransposon-like sequences and several novel repetitive DNA sequences from P. ginseng were used to differentiate P. ginseng from P. quinquefolius, and should be useful for evolutionary studies of these disjunct species.