Compared with living spray method, it focused on the investigation of different inoculation methods, various inoculation concentration and the influence of different seeding age on soft rot-resistance in Jinxianlian. The results showed that (1) Inoculated with dropping connection, the difference of disease index between A. roxburghii and A. formosanus was grate, so that the disease-resistance could be obviously distinguished. (2) When the inoculation concentration was 1.0 x 10(7) cfu x mL(-1), the difference of disease index was relatively obvious and the disease-resistance could be differentiated well. (3) At the moment of 4-month seeding inoculation, a certain difference of the disease index between A. roxburghii and A. formosanus was existed, so, relatively, it could accurately reflect the resistance difference between various species. With the inoculation of dropping connection, A. roxburghii and A. formosanus of 4-month seeding age was put in the bacteria suspension of inoculation concentration of 1.0 x 10(7) cfu x mL(-1). The identification was taken up after 5 days in the incubator under the condition of 14 h daylight and 28 degrees C. The identification result was conformed with that of the living spray method. To investigate the identification method of in vitro evaluation of soft rot-resistance of Jinxianlian so as to provide the foundation for germplasm utilization and excellent cultivars breeding.
Plant Diseases ; microbiology

Root rot disease is vital disease of Coptis chinensis, it has bursted in most producing area in recent years, and has caused severe damage. To identify the pathogenic fungi, Fusarium spp. fungi were isolated from rot root, of which the pathogenic fungi were screened with inoculation on C. chinensis root and plant, and identified with molecular and morphological method. The 20 Fusarium spp. fungi were obtained, of which 5 displayed high pathogenicity. It was deduced that F. oxysporum, F. solani and F. tricinctum were the pathogen, possibly pioneer pathogen of C. chinensis root rot disease. Among which F. oxysporum was dominant and deserved to pay more attention. High temperature and high humidity can increase pathogenicity of Fusarium spp. So the global climate warming may lead to temperature rising of C. chinensis producing area and favor the pathogen fungi, which may be one of the main factors leading to bursting of C. chinensis root rot disease. To control the root rot, beside developing and using pesticide, producing base should be moved to a high altitude area.
Coptis/microbiology* ; Fusarium/pathogenicity* ; Plant Diseases/microbiology* ; Plant Roots/microbiology*

Root rot is a microbial disease that is difficult to control and can result in serious losses in the planting of most Chinese medicinal materials. As high as 87.6% of roots or rhizomes of Chinese medicinal materials are susceptible to root rot, which seriously affects the cultivation development of Chinese medicinal materials. Trichoderma fungi, possessing biological control functions, can induce plants to improve their resistance to microbial diseases, promote plant growth, and effectively reduce the losses caused by various microbial diseases on cultivation. At present, Trichoderma is rarely used in the cultivation of Chinese medicinal materials, so it has great application potential for the prevention and control of root rot diseases in farmed Chinese medicinal materials. Based on the above situation, after comparison and discussion, it is believed that compared with chemical control and physical control, biological control of root rot diseases of Chinese medicinal materials is more efficient and meets the development needs of Chinese medicinal materials ecological planting in China. This paper reviewed the progress in the research and application of Trichoderma in the control of root rot diseases in the root and rhizome of farmed Chinese medicinal materials in the past 10 years and found that most of the current research on the biological control of root rot diseases in Chinese medicinal materials was mostly limited to the verification of the inhibitory effect of Trichoderma strains on the growth of the pathogenic microbes. Studies on the induction effect of Trichoderma on Chinese medicinal materials are not in depth. Studies on the responding mechanisms of most Chinese medicinal materials to Trichoderma are highly absent. Moreover, there are few reports on field experiments, which indicates that there is a long way to go before Trichoderma is widely applied in the farming practice of Chinese medicinal materials. To sum up, this paper aimed to link the present and the future and advocated further relevant research and more experiments on the application of Trichoderma in the farming of Chinese medicinal materials.
Agriculture ; Farms ; Plant Diseases/microbiology* ; Rhizome ; Trichoderma

In order to scientifically prevent and control Dendrobium catenatum southern blight disease,the main factors related to this disease occurrence,the pathogen( Sclerotium delphinii),environmental factors( temperature and humidity) and D. catenatum germplasms,were investigated. The results showed that reaching 25-30 ℃ temperature and over 95% humidity simultaneously should be the main conditions for the occurrence and prevalence of D. catenatum southern blight disease. Moreover,the S. delphinii-infected plants and their contaminated substrates were the disease spreading sources. Therefore,removing the infected plants,dealing with the contaminated substrates,keeping air ventilation,and reducing air humidity are the effective ways to prevent and control the occurrence and prevalence of D. catenatum southern blight disease. The research also indicated that D. catenatum has different resistances to the southern blight disease depending on germplasm. The present study lays important foundations for the breeding of D. catenatum diseaseresistant varieties and the further analysis of the infection and resistance mechanisms underlying southern blight disease.
Basidiomycota ; pathogenicity ; Dendrobium ; microbiology ; Humidity ; Plant Diseases ; microbiology ; Temperature

The aquatic grass Zizania latifolia grows symbiotically with the fungus Ustilago esculenta producing swollen structures called Jiaobai, widely cultivated in China. A new disease of Z. latifolia was found in Zhejiang Province, China. Initial lesions appeared on the leaf sheaths or sometimes on the leaves near the leaf sheaths. The lesions extended along the axis of the leaf shoots and formed long brown to dark brown streaks from the leaf sheath to the leaf, causing sheath rot and death of entire leaves on young plants. The pathogen was isolated and identified as the bacterium Pantoea ananatis, based on 16S ribosomal RNA (rRNA) gene sequencing, multilocus sequence analysis (atpD (β-subunit of ATP synthase F1), gyrB (DNA gyrase subunit B), infB (translation initiation factor 2), and rpoB (β‍-subunit of RNA polymerase) genes), and pathogenicity tests. Ultrastructural observations using scanning electron microscopy revealed that the bacterial cells colonized the vascular tissues in leaf sheaths, forming biofilms on the inner surface of vessel walls, and extended between vessel elements via the perforated plates. To achieve efficient detection and diagnosis of P. ananatis, species-specific primer pairs were designed and validated by testing closely related and unrelated species and diseased tissues of Z. latifolia. This is the first report of bacterial sheath rot disease of Z. latifolia caused by P. ananatis in China.
Pantoea/genetics* ; Plant Diseases/microbiology* ; Poaceae/microbiology* ; Virulence

Fungal disease is an important factor restricting the healthy development of Gastrodia elata industry. The control of fungal disease in G. elata is an important issue in production. This paper makes a detailed investigation on the current situation of G. elata disease in China through statistics on the failure rate, rotten pit rate and occurrence rate of G. elata disease in the main producing areas of China. It was found that G. elata disease was mainly infected from the top bud and junction, causing the occurrence rate of disease was 6%-17%, and the yield decreased by 10%-30%. The 23 dominant fungi were isolated from 18 typical G. elata disease samples. Through identification of colony morphology, mycelium morphology, spore morphology and genetic characteristics, they were finally identified as 13 species, belonging to 7 families and 7 genera. Trichoderma harzianum, Ilyonectria sp. and Ilyonectria destructans are the most frequently separated. Their isolation frequency were 22.22%,16.67%,16.67% respectively. Ilyonectria sp. and I. destructans were the first time isolated from G. elata disease samples. They may be the main pathogens causing soil-borne diseases of G. elata. T. harzianum has certain potential as Gastrodia biocontrol bacteria. This study can provide a theoretical basis for the research and development of control technology of Gastrodia fungi disease.
China ; Fungi/pathogenicity* ; Gastrodia/microbiology* ; Plant Diseases/microbiology*

UNLABELLEDTo study the infected root of Panax quinquefolium on the contents of ginsenosides.

METHODThe contents of three major ginsenosides Rg1, Re and Rb1 were determined by HPLC compared quantitatively between the different degree infected roots and normal root in the phloem and xylem.

RESULTRg1 in phloem and xylem of varying degrees infected root showed no significant difference, but Rb1 decreased 26.3% and 28.3% respectively in medium and serious infected roots comparing to normal root. Re in phloem of seriously infected roots decreased in xylem significantly.

CONCLUSIONThe results indicate that the variation of ginsenosides in different degrees infected roots exists and the proportion of Rg1, Re and Rb1 in the total ginsenosides changes.

Ginsenosides ; chemistry ; Panax ; chemistry ; microbiology ; Plant Diseases ; microbiology ; Plant Roots ; chemistry ; microbiology

The Astragalus membranaceus root rot disease,a soil-borne disease,has become increasingly severe in Shanxi province.This study was aimed at getting antagonistic Bacillus with excellent bio-control effects,and determining its effects on bacterial communities in root zone soil. With Fusarium solani and F. acuminatum as the target,antagonistic Bacillus was selected through such tests as living body dual culture,antifungal effect of bacteria-free filtrate,mycelia growth inhibition in vitro and control effect in detached roots,and identified with morphology,physio-biochemical characteristics and 16 S r DNA sequence analysis. The results showed that the Bacillus strain SXKF16-1 had obvious antifungal effect. The diameter of inhibition zone of its bacteria-free filtrate to F. solani and F. acuminatum was( 25. 90±1. 18) mm and( 25. 86±1. 85) mm respectively,and showed a lasting inhibition effect to mycelia growth. The disease index of the protective treatment and that of the cure treatment in detached roots test to F. solani and F. acuminatum were( 37. 50±8. 58),( 41. 67±4. 90) and( 25. 00±8. 33),( 38. 89±9. 62) respectively,both being significantly different( P<0. 05) from that of the control. The strain SXKF16-1 was identified as Bacillus atrophaeus. The B. atrophaeus SXKF16-1 showed significantly inhibition effect to pathogen causing root rot and could increase the bacterial diversity in root zone soil. It has potential to be developed as a special biocontrol agent.
Astragalus Plant/microbiology* ; Bacillus/physiology* ; Biological Control Agents ; Fusarium/pathogenicity* ; Plant Diseases/prevention & control* ; Plant Roots/microbiology* ; Soil Microbiology

The objective of this work was to analyze the soil microbial community diversity and structure in Panax quinquefolius rhizosphere and elucidated the rules of the ecology shift. Two community-based microbiological measurements, community level physiological profiling (CLPP) using Biolog sole C source utilization tests and phospholipid ester-linked fatty acid (PLFA) profiles, were used to evaluate soil microbial community function and composition of different Panax quinquefolius cropping soils. The properties, pH, N, P, K and organic matter were analyzed also. There were many differences in soil properties such as lower pH (5.82) in Jilin soil but higher pH (8.27) in Beijing soil and there were significant higher content of organic matter, available N, P, K in Jilin soil than those in Beijing soil. The analysis of soil microbial ecology showed a similar result in AWCD, Biolog and PLFA pattern. According to the PC1 score in principal analysis of Biolog and PLFA, the soils in 2, 3 and 4 years cultivated P. quinquefolius rhizophere were distinguished from the control and 1 year soils. The result indicated that the metabolism function reduced and the structure shifted in rhizophere soil microbial community after P. quinquefolius cropping. These may be the primary reason of the disease occur severely in P. quinquefolius field.
Biodiversity ; Panax ; microbiology ; Plant Diseases ; microbiology ; Rhizosphere ; Soil ; analysis ; Soil Microbiology

OBJECTIVETo isolate and identify pathogen of the seedling blight occurred in Platycodon grandiflorum.

METHODThe morphological observation, rDNA ITS sequence analysis, and Koch's postulates were used to identify the isolates of the causal agent.

RESULTThe isolates of the causal agent was Rhizoctonia solani.

CONCLUSIONThe result confirmed that R. solani is the pathogen of seedling blight of P. grandiflorum.

Molecular Sequence Data ; Phylogeny ; Plant Diseases ; microbiology ; Platycodon ; microbiology ; Rhizoctonia ; classification ; genetics ; isolation & purification ; Seedlings ; microbiology