Rusty Root Research Articles

Whole-genome and time-course dual RNA-Seq analyses reveal chronic pathogenicity-related gene dynamics in the ginseng rusty root rot pathogen Ilyonectria robusta

Ilyonectria robusta causes rusty root rot, the most devastating chronic disease of ginseng. Here, we for the first time report the high-quality genome of the I. robusta strain CD-56. Time-course (36 h, 72 h, and 144 h) dual RNA-Seq analysis of the infection process was performed, and many genes, including candidate effectors, were found to be associated with the progression and success of infection. The gene expression profile of CD-56 showed a trend of initial inhibition and then gradually returned to a profile similar to that of the control. Analyses of the gene expression patterns and functions of pathogenicity-related genes, especially candidate effector genes, indicated that the stress response changed to an adaptive response during the infection process. For ginseng, gene expression patterns were highly related to physiological conditions. Specifically, the results showed that ginseng defenses were activated by CD-56 infection and persisted for at least 144 h thereafter but that the mechanisms invoked were not effective in preventing CD-56 growth. Moreover, CD-56 did not appear to fully suppress plant defenses, even in late stages after infection. Our results provide new insight into the chronic pathogenesis of CD-56 and the comprehensive and complex inducible defense responses of ginseng root to I. robusta infection.

Microbial Community Changes in the Rhizosphere Soil of Healthy and Rusty Panax ginseng and Discovery of Pivotal Fungal Genera Associated with Rusty Roots.

Panax ginseng Meyer, a valuable medicinal plant, is severely threatened by rusty root, a condition that greatly affects its yield and quality. Studies investigating the relationship between soil microbial community composition and rusty roots are vital for the production of high-quality ginseng. Here, high-throughput sequencing was employed to systematically characterize changes in the soil microbial community associated with rusty roots. Fungal diversity was lower in the soils of rusty root-affected P. ginseng than in those of healthy plants. Importantly, principal coordinate analysis separated the fungal communities in the rhizosphere soils of rusty root-affected ginseng from those of healthy plants. The dominant bacterial and fungal genera differed significantly between rhizosphere soils of healthy and rusty root-affected P. ginseng, and linear discriminant analysis effect size (LEfSe) further indicated a strong imbalance in the soil microbial community of diseased plants. Significantly enriched bacterial genera (including Rhodomicrobium, Knoellia, Nakamurella, Asticcacaulis, and Actinomadura) were mainly detected in the soil of rusty root-affected P. ginseng, whereas significantly enriched fungal genera (including Xenopolyscytalum, Arthrobotrys, Chalara, Cryptococcus, and Scutellinia) were primarily detected in the soil of healthy plants. Importantly, five fungal genera (Cylindrocarpon, Acrophialophora, Alternaria, Doratomyces, and Fusarium) were significantly enriched in the soil of rusty root-affected plants compared with that of healthy plants, suggesting that an increase in the relative abundance of these pathogenic fungi (Cylindrocarpon, Alternaria, and Fusarium) may be associated with ginseng rusty roots. Additionally, this study is the first to report that an increase in the relative abundances of Acrophialophora and Doratomyces in the rhizosphere of P. ginseng may be associated with the onset of rusty root symptoms in this plant. Our findings provide potentially useful information for developing biological control strategies against rusty root, as well as scope for future screening of fungal pathogens in rusty roots of P. ginseng.

Purification and Characterization of a Novel Antifungal Flagellin Protein from Endophyte Bacillus methylotrophicus NJ13 against Ilyonectria robusta

Endophyte Bacillus methylotrophicus NJ13 was isolated from Panax ginseng. Its sterile fermentation liquid showed a significant inhibitory effect against Ilyonectria robusta, causing the rusty root rot of P. ginseng and P. quinquefolius. The antifungal protein was obtained after precipitation by 20% saturated ammonium sulfate, desalted by Sephadex G-25, weak anion exchange chromatography, and gel filtration chromatography. SDS-PAGE showed that the purified protein was approximately 29 KDa. The antifungal protein after desalting was not resistant to temperatures higher than 100 °C, resistant to acid conditions, and did not tolerate organic solvents and protease K. The amino acid sequence of purified antifungal protein had an identity of 76% to flagellin from Bacillus velezensis. The isoelectric point of the protein was 4.97 and its molecular mass was 27 KDa. Therefore, a specific primer G1 was designed based on the flagellin gene sequence, and a 770 bp gene sequence was cloned in NJ13 genomic DNA, which shared the same size of flagellin. There were ten base differences between the gene sequences of flagellin and the cloned gene, however, the amino acid sequence encoded by the cloned gene was identical to the flagellin. In conclusion, the antifungal protein produced by biocontrol agent NJ13 contained a flagellin protein.

First Report of Ilyonectria vredehoekensis Causing Rusty Root on American Ginseng in China

First Report of <i>Ilyonectria vredehoekensis</i> Causing Rusty Root on American Ginseng in China

First Report of Dactylonectria novozelandica Associated with Rusty Root of Panax quinquefolius in China

First Report of <i>Dactylonectria novozelandica</i> Associated with Rusty Root of <i>Panax quinquefolius</i> in China

Analysis of rhizosphere bacterial and fungal communities associated with rusty root disease of Panax ginseng

Rusty root is a widespread problem in ginseng production, which can reduce ginseng quality and root price. The formation of rusty root is a complex process caused by multiple factors, primarily soil physicochemical factors and microorganisms. However, the precise roles played by these factors in the development of this disease remain unclear, especially the role of microorganisms. Deciphering the structure of the rhizosphere microbial communities will provide a more comprehensive and deeper understanding of rusty root disease. Rhizosphere microbial communities from five ginseng fields with different rusty root grades and indices were characterized by MiSeq sequencing. The pattern of beta diversity indicated that rusty root disease might be positively correlated with bacterial community structure, but not with fungal community structure. Rusty root may be caused by excessive Fe (II) oxidation and Fe (III) deposition accompanied by aluminum (Al) and manganese (Mn), in which nitrate-dependent Fe (II)-oxidizing bacteria, including Acidobacteria, Chloroflexi, and Nitrospirae, play a driving role. Moreover, the accumulation of iron (Fe), Al, and Mn could enhance growth and weak invasion of some fungi, thus exacerbating the rust symptoms. However, no correlation was found between the relative abundance of the genus Ilyonectria and rusty root grade or index (P > 0.05); suggesting that Ilyonectria species may not be essential for rusty root disease. Thus, the oxidation and deposition of rhizosphere Fe, Al, and Mn facilitated by nitrate-dependent Fe (II)-oxidizing bacteria might be key factors contributing to rusty root disease. Further studies on the inhibition of Fe, Al, and Mn transformation and accumulation, and application of iron/nitrogen-cycling related bacteria in ginseng soil might elucidate effective methods for preventing rusty root.

Unveiling of Dominant Fungal Pathogens Associated With Rusty Root Rot of Panax notoginseng Based on Multiple Methods

Root rot is an important disease hampering the sustainable cultivation of Panax notoginseng. Culture-dependent and independent techniques were used to elucidate the dominant fungal pathogen of rusty root rot of P. notoginseng. Based on Illumina sequencing profiles for fungi using ITS primers, five phyla-namely Ascomycota, Basidiomycota, Glomeromycota, Zygomycota, and Chytridiomycota-were identified, and the analyses showed that the Ascomycota was the dominant phylum (∼50 to 97%), especially in the symptomatic samples. Out of 226 total genera identified, seven genera had over 1% average abundance, including Ilyonectria, Fusarium, Tetracladium, Cladosporium, Rhizophagus, Alternaria, and Perisporiopsis. However, only Ilyonectria was the predominant genera in the symptomatic samples (∼76 to 80%), while the others, including Fusarium, had higher abundances in asymptomatic samples. Based on in vitro and in vivo pathogenicity, the isolate G3B was demonstrated to be the pathogen causing rusty root rot of P. notoginseng, and it was identified as Ilyonectria mors-panacis. Based on primers F2-R2 targeting the His3 gene of Ilyonectria, real-time quantitative PCR (qPCR) was performed as an additional proof confirming that I. mors-panacis was the dominant pathogen in the symptomatic samples during the years of the study (2014-2015).

Growth characteristics and ginsenoside contents of Korean ginseng (Panax ginseng C.A. Meyer) by shade materials and green manure crops

ABSTRACT This research carried out to figure out the effect of the green manure crop cultivated at a preparation field and the shading net on the growth, development, and quality of ginseng. Followings are results obtained from the research. Leaf width of ginseng under the shading net of a two-layered blue and two-layered black polythylene net (TBTBPN) was good at rye and hairy vetch cultured group. Leaf length of ginseng under the shading net of a three- layered blue and one-layered black polyethylene net (TBOBPN) was good at barley and hairy vetch cultured group. Meanwhile, leaf width was good at hairy vetch cultured group. Leaf length of ginseng under a blue polyethylene sheet (BPS) was good at a barley and barley + hairy vetch cultured group, but stem length was shorter compare to other shading net cultivations. Root weight of ginseng was good under the shading net of a two-layered blue and two-layered black polyethylene net (TBTBPN) at a rye and hairy vetch cultured group, and was good under the shading net of a three-layered blue and one- layered black polyethylene net (TBOBPN) at a barley + hairy vetch cultured group, but there was no significant difference under blackout screen according to manure crop varieties. Ratio of rusty root was 10.2% at the barley cultured group under the shading net of a two-layered blue and two-layered black polyethylene net (TBTBPN), and was 23.1% at hairy vetch cultured group under shading net of a three-layered blue and one-layered black polyethylene net (TBOBPN). Ratio of rusty root was the lowest at a rye cultured group regardless the shading nets. Content of the ginsenoside was the highest at the rye cultured group under the shading net of two-layered blue and two-layered black polyethylene net (TBTBPN), was the highest at the barley cultured group under the shading net of a three-layered blue and one-layered black polyethylene net (TBOBPN), and was the highest at the rye cultured group under the blackout screen.Keywords : ginseng, green manure crop, shade net, ginsenoside

Analysis of the relationship between rusty root incidences and soil properties in Panax ginseng

Rusty root is a serious problem in ginseng cultivation that limits the production and quality of ginseng worldwide. The Changbai Mountains are the most famous area for ginseng cultivation in China. To clarify the relationship between rusty root and soil characteristics, physico-chemical properties and enzymatic activities of soil collected from five different fields in the Changbai Mountains were analyzed and a controlled experiment carried out by increasing the concentration of Fe (II). Soil bulk density, moisture, total iron (Fe) and total manganese (Mn) concentrations and polyphenol oxidase (PPO) activity were significantly higher in rusty root than healthy root groups (two-sample test, P<0.05 or P<0.01), respectively. Pearson test showed that there was a significant positive correlation between rusty root index and pH, N, Fe, Mn, Al, Zn and Ca of soil samples collected from fields (P<0.05 or P<0.01), and a significant positive correlation also occurred between rusty root index and Fe (II) added to soil in Fe (II) inducing rusty root (P<0.01). Physiological factors may be very important roles giving rise to ginseng rusty root. Fe (III) reduction and Fe (II) oxidation could be important in increasing the incidence of rusty root. Soil moisture and bulk density of non-rhizosphere soil not attached to the root surface, and pH, N and PPO content of rhizosphere soils attached to the root surface were heavily involved in the reduction, oxidation and sequestration of metal ions.

Growth Characteristics and Ginsenoside Contents of 4 Years Old Korean Ginseng (Panax ginseng C.A. Meyer) by Shade Materials and Green Manure Crops

This research carried out to figure out the effect of the green manure crop cultivated at a preparation field and the shading net on the growth, development, and quality of ginseng. Followings are results obtained from the research. Leaf width of ginseng under the shading net of a two-layered blue and two-layered black polythylene net (TBTBPN) was good at rye and hairy vetch cultured group. Leaf length of ginseng under the shading net of a three-layered blue and one-layered black polyethylene net (TBOBPN) was good at barley and hairy vetch cultured group. Meanwhile, leaf width was good at hairy vetch cultured group. Leaf length of ginseng under a blue polyethylene sheet (BPS) was good at a barley and barley + hairy vetch cultured group, but stem length was shorter compare to other shading net cultivations. Root weight of ginseng was good under the shading net of a two-layered blue and two-layered black polyethylene net (TBTBPN) at a rye and hairy vetch cultured group, and was good under the shading net of a three-layered blue and onelayered black polyethylene net (TBOBPN) at a barley + hairy vetch cultured group, but there was no significant difference under blackout screen according to manure crop varieties. Ratio of rusty root was 10.2% at the barley cultured group under the shading net of a two-layered blue and two-layered black polyethylene net (TBTBPN), and was 23.1% at hairy vetch cultured group under shading net of a three-layered blue and one-layered black polyethylene net (TBOBPN). Ratio of rusty root was the lowest at a rye cultured group regardless the shading nets. Content of the ginsenoside was the highest at the rye cultured group under the shading net of two-layered blue and two-layered black polyethylene net (TBTBPN), was the highest at the barley cultured group under the shading net of a three-layered blue and one-layered black polyethylene net (TBOBPN), and was the highest at the rye cultured group under the blackout screen.

인위적인 습해 유발조건에서 2년생 인삼 품종의 생육특성

This study was conducted to investigate growth characteristics to develop the technique to select resistant cultivar by wet injury at an early stage through the automatic irrigation maintaining 30, 20, 10 kPa respectively using native variety, Chunpoong, Yunpoong, Gumpoong and Sunun. The aerial growth was decreased at 10 kPa compared to 30 kPa. In addition, the survival rate was decreased by 66.6%, 62.3%, 33.8% at 30, 20, 10 kPa, respectively. The survival rate of Chunpoong and Gumpoong were higher than others at 10 kPa. While root growth characteristics such as root length, root weight, number of lateral root and side root were tended to decrease, root diam was no significant or increased. And the more humid condition is, the more the incidence rate of rusty root and rough skin were tended to increase. The epidermal thickness of Chunpoong and Gumpoong was increased but the figures of native variety, Yunpoong and Sunun were decreased at 10 kPa compared to 30 kPa. But, the tissue stiffness of root was decreased at 10 kPa compared to 30 kPa.

Angela, Agnes, Esther, and Ivy

Angela, Agnes, Esther, and Ivy Amy C. Evans (bio) Pearl spiked her drink. And then I made a painting about it. I like to think of my paintings as portraits, each one a document of a specific moment in someone’s life. But the people are strangers, and their stories are told in my imagination. It all starts with an object. I’m constantly seeking out vintage packaging, fabric, and accessories to illustrate the lives of the people—mostly women—I want to introduce to viewers. When seemingly unrelated objects fall next to each other, they add meaning to the mundane and become unique portraits, the individual elements coming together to offer a peek into the conjured lives of my motley cast of characters. I feel a kinship with these women—all strong, independent ladies who might be just a little bit set in their ways—and the titles of the pieces offer glimpses into their oddball thoughts and routines. (Of course, Pearl likes bourbon with her Tang.) I gravitate to food-related packaging for its connection to another era—one of cheese-laden casseroles, mayonnaise-drenched salads, and strong drinks at lunch. These gals cook from cans and boxes so they can spend their time on other, more important things. My home studio is full of vintage trinkets and treasures that find their way into my paintings. The rusty root beer lid from a barbecue joint in Tennessee, butter packaging from New Orleans, or an oyster shell I slid into my pocket on a trip to Florida are the kinds of things that are tucked into the nooks and crannies of my creative space. Some items get recycled and crop up in multiple paintings (I’m particularly fond of rabbit’s foot key chains), creating a personal iconography that I rely on to help tell these stories. The finished paintings are objects in themselves. All of my portraits are done in acrylic on wood panels and finished with a coat of varnish, adding depth to the image and making the object more durable—like a final coat of nail polish. I’d like to hang out with Pearl, wouldn’t you? [End Page 8] Click for larger view View full resolution Agnes loved combing mayonnaise through her hair curls, 24×24”, acrylic on wood panel, 2014. [End Page 9] Click for larger view View full resolution Pearl spiked her drink, 11×16”, acrylic on wood panel, 2012. [End Page 10] Click for larger view View full resolution Marge had her usual breakfast, and then she took her usual measurements, 24×24”, acrylic on wood panel, 2014. [End Page 11] Click for larger view View full resolution Vi went home to celebrate, 16×24”, acrylic on wood panel, 2012. [End Page 12] Click for larger view View full resolution Esther set her hair before massaging her feet, 24×12”, acrylic on wood panel, 2014. [End Page 13] Click for larger view View full resolution Angela ran a bath, lit a cigarette, and read some poetry, 24×12”, acrylic on wood panel, 2014. [End Page 14] Amy C. Evans Amy C. Evans is an artist and independent documentarian based in Houston, Texas, and served as the oral historian for the Southern Foodways Alliance for twelve years. Whether picking up an old lard can at an antique mall and wondering about the life of its previous owner or interviewing a soul food cook about his signature sweet potato pie, Amy is constantly curious about the lives of others. She also happens to appreciate a good meringue and can never eat too many oysters. You can see more of her work at www.amycevans.com. Copyright © 2015 Center for the Study of the American South

First Report of Ilyonectria robusta Causing Rusty Root of Asian Ginseng in China.

Asian ginseng (Panax ginseng) is an economically important perennial herb, mainly cultivated in Jilin Province, China. In September 2013, Asian ginseng plants in Jilin showed rusty root symptoms. Typical symptoms included rusty superficial lesions of irregular shapes and margins. Ten symptomatic roots were collected from each of five fields for investigation. To isolate the pathogen, root epidermal tissues with typical lesions were excised, surface-sterilized, and placed on potato dextrose agar (PDA) amended with 50 μg/ml tetracycline. After incubation at 20 ± 1°C in the dark for a week, 18 single-spore isolates out of 50 samples were obtained and identified as Ilyonectria robusta (A.A. Hildebr.) A. Cabral & Crous based on morphological characters and DNA sequence analysis (1). After incubating 7 days on PDA in the dark at 20°C, colonies were cottony to felty in texture and orange white to brownish grey in color with average diameters of 60 ± 3 mm. Isolates were cultured on synthetic nutrient-poor agar for conidial measurements. Macroconidia formed on simple conidiophores predominately, with mostly one and occasionally up to three septa, and were cylindrical with both ends broadly rounded. Macroconidia varied in size depending on the number of cells as follows: one-septate, 7.0 ± 0.6 × 27.7 ± 2.7 μm; two-septate, 7.3 ± 0.7 × 33.3 ± 2.1 μm; three-septate, 7.4 ± 0.6 × 33.4 ± 2.2 μm. Microconidia that formed on complex conidiophores were ellipsoid to ovoid and ranged in size from aseptate 3.7 ± 0.5 × 8.7 ± 1.1 μm to one-septate 5.0 ± 0.6 × 13.1 ± 1.6 μm. Brown chlamydospores were abundantly produced on PDA, globose to subglobose in shape, and in size of 10.9 ± 1.3 × 11.8 ± 1.5 μm (n ≥ 30 observations per structure for each measurement). The isolates were further classified by amplifying and sequencing the ITS1-5.8S rRNA-ITS2 region and histone H3 gene with primer pairs ITS5 and ITS4 (4), and H3-1a and H3-1b (3), respectively. Sequences of the two loci (GenBank Accession Nos. KM015300 and KM015299) showed 100% identity among the three examined isolates and the published I. robusta isolates (JF735268 and JF735517). To confirm the pathogenicity, bare roots of 3-year-old Asian ginseng were inoculated with mycelial plugs of three isolates of I. robusta selected randomly. Four roots were inoculated as replicates for each isolate with pathogen-free agar plugs as a control. One week post-inoculation in the dark at 20 ± 1°C, all the inoculated ginseng roots showed light-brown to dark-brown lesions. I. robusta was recovered from symptomatic roots and confirmed by analyzing the DNA sequence of the histone H3 gene. The inoculation experiment was repeated, and both trials showed the same results. The ginseng tissue under the control agar plugs remained symptomless, and no fungi were isolated. To our knowledge, this is the first report of I. robusta causing rusty root of P. ginseng in China (1,2,5).

First Report of Rhexocercosporidium panacis Causing Rusty Root of Panax ginseng in Northeastern China.

In northeastern China, Asian ginseng (Panax ginseng) roots exhibited reddish brown lesions of various sizes, irregular shapes, and diffuse margins, typical of rusty root disease. The lesions remain superficial, smooth, and limited to the epidermal and peridermal tissues. In September 2013, 10 symptomatic roots were collected from each of three fields in Jilin and Heilongjiang provinces. One piece of symptomatic skin tissue from each root was excised, surface-disinfested in 1% NaClO for 3 min, rinsed three times with sterile water, and then placed on tetracycline-amended (50 μg/ml) potato dextrose agar. After incubation at 22 ± 1°C in the dark for a week, small olivaceous black colonies developed from the symptomatic tissue from five of the 30 samples. No spores were observed. A single hyphal tip of each colony was transferred to a fresh V8 agar plate to purify the culture. Two-week-old colonies on V8 agar were olivaceous gray, and 42 to 46 mm in diameter with an outer white margin (3 to 5 mm wide). Conidia produced in V8 broth after 3 weeks with a 12-h photoperiod were straight and hyaline, cylindrical or subcylindrical with no or one septum. Mature conidia were 12.8 to 21.8 × 2.2 to 4.5 μm (mean 18.2 × 3.0 μm, n = 100 conidia for each of three isolates). Three isolates selected randomly were further identified by analyzing the partial sequences of the ITS region of rDNA with primers ITS4 and ITS5 (5), and partial sequences of β-tubulin with the primers tub2F and tub2R (1). Sequences of the three isolates (GenBank Accession Nos. KJ149287, KJ149288, and KJ149290 to 93) showed 99% to 100% homology with previously identified and deposited Rhexocercosporidium panacis isolates (DQ2499992 and DQ457119) for both loci (3). Therefore, the three isolates were identified as R. panacis and deposited in China General Microbiological Culture Collection Center (CGMCC3.17259 to 61). Pathogenicity of R. panacis in Asian ginseng was investigated using these three isolates as described previously with slight modifications (4). Bare roots of 3-year-old Asian ginseng were surface-disinfested as described above, and inoculated with mycelial plugs (4 mm diameter) cut from the margin of actively growing colonies of the isolates on V8 agar. Three mycelial plugs were placed on each root at 3-cm intervals and four roots (replicates) were inoculated for each isolate. Four additional roots were inoculated with non-colonized agar plugs as control. The treated roots were placed on moist filter paper in an enamel tray. The plates were sealed with plastic wrap to prevent desiccation and incubated in the dark at 18 ± 1°C. Four weeks post inoculation, all the inoculated ginseng roots showed red-brown lesions, which turned to dark red or black over time. R. panacis was recovered from symptomatic roots for all isolates and confirmed by ITS sequence analysis. The mock-inoculated control roots remained symptomless and no R. panacis was isolated. The inoculation experiment was repeated and showed the same results. R. panacis was reported in 2006 to infect roots of Panax quinquefolius (2,3,4). To our knowledge, this is the first report of R. panacis causing rusty root of P. ginseng.

비닐하우스에서 상토의 조성에 따른 묘삼의 생장특성

This study was conducted to find out the optimum composition of nursery soil for raising seedling of ginseng (Panax ginseng C. A. Meyer). Total 9 kinds of raw materials were used such as peat-moss, perlite, leaf mould, rice bran, gull's guano, castor-oil plant bark, palm bark, cow manure and chicken manure for optimum composition of nursery soil in ginseng. Occurrence of damping-off in ginseng was lowered about 50% in nursery soil type 1, 2 and 4 than in other types nursery soil in June, and occurrence rate of rusty root also lowest in nursery soil type 1. As the salinity of nursery soil increased, so did the occurrence of physiological disorder in ginseng seedling. The cause of salinity increasing in nursery soil has closely relation to NO3-N, P2O5 and Na + content. Plant height, root length, diameter and weight were longer and heavier in nursery soil type 1 (mixing ratio of peat-moss, perlite and leaf mould was 50 : 20 : 30 based in volume) than in other types of nursery soil. So nursery soil type 1 was selected for raising seedling of ginseng. pH and electric conductivity (EC) of selected nursery soil type 1 was 5.55 and 0.13 dS/m. Contents of NO3-N and P2O5 were 21.0 and 40.0 ㎎/L, and K + 0.36, Ca 2+ 3.38, Mg 2+ 2.01 and Na + 0.09 cmol + /L, respectively.

녹비작물 재배에 따른 인삼의 생육과 진세노사이드 함량

본 연구는 안정적 인삼재배를 위하여 여러 가지 녹비작물을 이용하여 인삼 예정지를 관리한 후 인삼생육과 진세노사이드 함량 등을 조사한 결과 다음과 같다. 인삼예정지 토양에 녹비작물을 재배하면 미생물상이 다양해지고, 유기물 함량과 Total-N 함량은 증가되며, 염류가 감소되는 경향을 보였다. 녹비의 생산량은 호밀이 가장 많았고, 녹비작물을 재배한 후 2년생 인삼의 지상부와 지하부의 생육은 유의적으로 증가하였으며 특히 호밀재배구가 가장 좋았다. 또한 인삼의 지상부 황증과 지하부의 적변 발생량은 호밀재배구가 가장 적었으며 진세노사이드 함량은 가장 높았다. 따라서 인삼재배지의 토양관리는 호밀을 재배하여 예정지를 관리하는 것이 좋을 것으로 판단된다. This study investigated ginseng growth and ginsenoside contents after control a reserved ginseng cultivation land using various green manure crops for stable ginseng cultivation. Followings are results obtained from this research. After cultivate the green manure crops, microbial flora in soil was diversified, organic matter and total-N content increased, but salt content decreased. The highest output obtained from the wheat cultivated area among various green manure corps. Growth of shoot and root of two years old ginseng increased significantly at the green manure crop cultivated area. Specially, the wheat cultivated area was the most effective in growth. Also, the rate of the leaf discoloration at the aerial part and the rusty root at the root was the least at the wheat cultivation area. Meanwhile, the ginsenoside content was the most at the wheat cultivation area. Thus, the reserved ginseng cultivation land could be managed by cultivating wheat for effective ginseng growth.

논토양에서 비닐하우스를 이용한 재배방법이 인삼의 수량 및 품질에 미치는 영향

The average and maximum temperature were 29.5℃ and 33.2℃ at 2:00 p.m. respectively, in the plastic-filmhouse covered with shade net, and both of temperature were lower 0.6℃ and 1.3℃ than those of conventional shade. Lighttransmittance was 14% in the plastic-film house, while 9.9% in conventional shade during growing season from May toOctober. Withering time of aboveground part was on October 3rd in conventional shade with 60% of withering leaf, while itwas on November 10th with 3.7% of withering leaf in the plastic-film house, about 40 days longer survival. The main diseaseincidence were 15% of anthracnose, 17% of leaf spot, 5% of phytophthora blight and 3% of gray mold in the conventionalshade, while 0 ~ 0.1% disease incidence and 95% of emergence rate in the plastic-film house. The growth in the abovegroundand underground part of ginseng was totally better, particularly characteristics affecting yield such as root length,main root length and diameter in the plastic-film house . The fresh weight was increased by 128% compared to the conventionalshade and harvested roots per 3.3 ㎡ were 36 roots in the conventional shade and 58 roots in the plastic-film house andfuthermore yield per 3.3 ㎡ was increased by 216% compared to the conventional shade. As covering materials, the ricestraw in the plastic-film house was excellent. The ginsenoside contents affecting the quality of ginseng were higher in theplastic-film house indicating 0.333% of Rg1, 0.672% of Rb1, 0.730% of Rc and rate of red rusty root was less than4.0 ~ 6.1%. Above the results, the quality of ginseng grown in the plastic-film house covered with shade net was improvedthan that of the conventional shade.

Screening and Identification of Antibacterial Actinomycetes against Bacteria Causing Rusty Root on Ginseng

Rusty root, the browning disease on ginseng, decreases quality and value. Recent studies indicated that endophytic bacteria could be a possible cause of rusty root. Actinomycetes antagonistic to the rusty-root-causing bacteria were isolated from soil. Twenty nine out of 932-isolates of Actinomycetes from soil showed antibacterial activity against Agrobacterium tumefaciens and Pseudomonas veronii an endophytic isolate in ginseng. The strongest antibacterial strain(ATO4O104) was classified based on 16S rDNA sequence. The Actinomycetes strain, ATO4O104, isolated in soil of USA volcano national park was identified as Streptomyces adephospholyticus. To test plant toxicity, radish seeds were sprouted with the culture of S. adephospholyticus and it did not show any harmful effect. The butanol partition out of n-hexane, ethyl acetate, butanol, and water partions showed the highest antibacterial activity.

Different Structural Modifications Associated with Development of Ginseng Root Rot Caused by Cylindrocarpon destructans

Root rot caused by Cylindrocarpon destructans is one of the most important diseases of ginseng (Panax ginseng C. A. Meyer). Two types of symptoms found in ginseng root rot are black root rot and rusty root (rusty spots), in which disease severities are high and low, respectively. Symptom development and related histopathological changes were examined in an inoculation test on 2-year-old ginseng roots using virulent (Cy9801) and avirulent (Cy0001) isolates of C. destructans under different temperature conditions (13, 18, 23, and 28oC). Black root rot was only induced by Cy9801 in the lower temperature range (13, 18, and 23oC) and not at the higher temperature (28oC). No black root rot, but only rusty spot symptoms, were induced by Cy0001 at all temperatures tested except 13oC, at which no symptoms occurred on over half of inoculation sites, suggesting disease development was influenced by pathogen virulence and temperature. Wound periderms were formed in all root tissues with rust spot symptoms at 28oC caused by Cy9801 and at 18, 23, and 28oC temperatures caused by Cy0001. No wound periderm was formed at 13oC by either Cy9801 or Cy0001. Light microscopy revealed that the wound periderm was formed by initial cell divisions in cell wall formation and/or additional cell wall layering in parenchyma cells without obvious nuclear division, followed by layering of the divided cells adjacent to the inoculation sites, blocking the spread of the rot. These results suggest that disease development declined at lower temperatures and by the formation of a wound periderm at higher temperatures, and that ginseng rusty root may develop under conditions unfavorable for further disease development of C. destructans.

Rusted Root of Ginseng (Panax quinquefolius) Is Caused by a Species of Rhexocercosporidium

ABSTRACT Rusted root (also known as rusty root) of ginseng (Panax quinquefolius) was first described over 70 years ago, but the causal agent has not been clearly established. The disease is characterized by slightly raised reddish-brown to black root lesions of varying size. The lesions, regardless of size, remain superficial; however, peridermal tissue is ruptured and sloughed off, giving the root a scabbed appearance. Culture-independent techniques were used to demonstrate that a fungal internal transcribed spacer (ITS) region DNA fragment was strongly associated with diseased but not healthy root tissue. The fragment ( approximately 650 bp in length) was cloned. Restriction enzyme digests of cloned DNA indicated that the 650-bp fragment represented a single taxon. BLAST analysis following sequencing of the fragment found that the nearest matches in GenBank were anamorphic genera associated with discomycetes, in particular Rhexocercosporidium spp. This putative identification was supported further by isolating fungi from diseased tissue using a semiselective agar medium. With this procedure, a Rhexocercosporidium-like fungus was isolated; DNA extracted from fungal cultures and amplified using ITS oligonucleotide primers was found to be identical to similarly amplified DNA from the 650-bp bands. However, the isolates were distinct, with respect to growth rate on agar media and ITS sequence, from Rhexocercosporidium carotae, the only described species in this genus. The ability to reproduce symptoms on ginseng roots was confirmed in pathogenicity tests. Oligonucleotide primers based on ITS sequences were designed to amplify DNA of Rhexocercosporidium spp. Polymerase chain reaction assays on DNA extracted from naturally infected root tissue showed that the fungus was present in nearly all symptomatic roots but was infrequent in healthy-appearing roots. The most probable cause of rusted root of ginseng is a previously undescribed species of Rhexocercosporidium.