Resistance of Microbial Community of Artemisia annua L.to Pathogenic Fungi

[Objectives]This paper was to figure out whether the dominant bacterial community has the role and effect of bacterial community and its defense mechanism against potential pathogenic fungi in Artemisia annua,and thus establish a systematic model of bacteria-fungus-plant.[Methods]Fifty-eight strains of bacteria and one strain of pathogenic fungi,Globisporangium ultimatum,were used for the experiments.These 58 bacterial strains were assembled into a bacterial community,and the bacteria with abundance in the top 1%were reassembled into a dominant bacterial community as measured by 16S rDNA.[Results]The growth of A.annua seedlings inoculated with bacterial communities and pathogenic fungi or dominant bacterial communities and pathogenic fungi was significantly better than that of A.annua seedlings inoculated with pathogenic fungi during in vitro confrontation,which was evident in both enzymatic and non-enzymatic antioxidant assays.[Conclusions]The results suggest that the dominant bacterial community has a crucial role as a representative core microbial community of synthetic bacterial community,which can protect plants by interfering with the growth of phytopathogenic fungi mediated by chemical signals,and can be used as the main synthetic community of biocides to achieve the effect of biocontrol.

In Vitro Antifungal Activity of the Extract and Compound from Acorus tatarinowii Against Seven Plant Pathogenic Fungi

Acorus tatarinowii Schott is a traditional Chinese medicine plant and has multiple bioactivities in medicine and pesticide field. In this study, the antifungal compound 1,2-dimethoxy-4（2-propenyl） benzene was isolated from A. tatarinowii Schott by activity-directed isolation method, and the inhibitory activity of the extract and 1,2-dimethoxy-4（2-propenyl） benzene against seven plant pathogenic fungi was evaluated. The results showed that the extract and 1,2-dimethoxy-4（2- propenyl） benzene had high inhibitory activity against hyphal growth of Thielaviopsis paradoxa （de Seynes） V. Hohnel, Pestalotia mangiferae P. Henn., Fusarium oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., Alternaria alternate Tanaka, Colletotrichum musae （Berk et Curt） V. Arx, Sphaceloma fawcettii Jenk., and Mycosphaerella sentina （Fr.） Schroter. The EC50 values of extract were 1.6162, 1.6811, 1.1253, 3.5771, 1.7024, 2.2284, and 2.2221 g L^-1, respectively, and the EC50 values of 1,2-dimethoxy-4（2-propenyl） benzene were 0.1021, 0.0997, 0.0805, 0.1742, 0.1503, 0.1853, and 0.1924 g L^-1, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene also inhibited spores germination of T. paradoxa （de Seynes） V. Hohnel and F. oxysporum f. sp. niveum （E. F. Smith） Syn. et Hans., with the inhibitory rates of 98.81 and 100% at a concentration of 0.4 g L^-1 after 8 h, respectively. 1,2-Dimethoxy-4（2-propenyl） benzene is a potential botanical antifungal agent for controling of plant fungal diseases.

A Preliminary Investigation of Pathogenic Fungi from Lotus(Nelumbo nucifera Gaertn)in Nanchang City

[Objectives]Lotus(Nelumbo nucifera Gaertn)is an economically important aquatic plant in China.Fungal disease is a serious problem in lotus cultivation.In this study,the pathogenic fungi on lotus in Nanchang City were investigated to lay the foundation for the disease control.[Methods]Lotus leaves and stems in ponds of Nanchang City were collected,the fungi on leave/stem spots were isolated and purified.Colonies morphological characters and ITS sequences were used to identify the strains.[Results]49 strains were isolated and identified to 20 species,belonging to 12 genera.[Discussion]15 species may firstly be reported on lotus in this study,i.e.,Alternaria angustiovoidea,Alternaria compacta,Alternaria ricini,Alternaria tenuissima,Arthrinium arundinis,Botryosphaeria dothidea,Curvularia spicifera,Diaporthe australiana,Diaporthe eres,Diaporthe tectonae,Epicoccum nigrum,Fusarium fujikuroi,Neofusicoccum parvum,Nigrospora sphaerica,and Phomopsis eucommii.

Toxicity of Lanthanum to Pathogenic Fungi and Its Morphological Characteristics

The inhibitory effects of La on the mycelial growth of several soil-borne pathogenic fungi including Rhizoctonia solani , Pythium sp., Fusarium solani , Selerotinia sclerotiorum , and Fusarium oxyspoxum were studied in vitro. The results show that the mycelial growth was inhibited strongly by the La, with EC50 of 130 - 320 mg·L^-1 and EC95 of about 550- 40007 mg·L^-1 respectively. In addition, the morphological toxicity of La was studied by using the scanning electronic microscope. Treated by La, the mycelial growth of pathogenic fungi was significantly restrained, and the morphological characteristics were found to be abnormal, such as increased ramification, malformation, partial swelling and shrinking, and irregularly entangled mycelial block or rhizomorph.

Antifungal Activity and Toxicity of Two New types of Polyene Antibiotics against Four Species of Rice Pathogenic Fungi

The antifungal activity and toxicity of new type polyene macrolide antibiotics-Antifungalmycin 702 and Fungichromin against Rhizoctonia solani, Hel- minthosporium sigmoideum Car. , Magnaporthe grisea and Ustilaginoidea virens were studied by mycelial growth rate method and mycelial dry weight method in vitro. The results showed that both of Antifungalmycin 702 and Fungichromin had strong antifungal activity against four speices of rice pathogenic fungi. Treated with 50 μmL Antifungalmycin 702 , the inhibitory rates of Antifungalmycin 702 agmnst R. solani, H. sigmoideum Cav., M. grisea and U. virens were 100%, 100%,91.20% and 68.10%, and EC50 and ECho were 7.00, 10.30, 14.41, 26.71 and 13.20, 17.66, 27.67,128.28 p.g/mL, respectively. Treated with 13 pg/mL Fungichremln, the inhibitory rates of Fungichromin against four speices of rice pathogenic fungi were 78.20%, 100%, 100% and 79.17%, and ECs0 and ECg0 were 1.47, 1.91, 2.37, 0. 20 and 41. （15, 3.92, 4.34, 135.54 gg/mL, respectively. The antifungal activity of Fungichromin was stronger than Antifungalmycin 702.

Selective Degradation of Mitochondria by Mitophagy in Pathogenic Fungi

Selective mitochondrial autophagy or mitophagy is an evolutionarily conserved cellular process that selectively degrades superfluous, damaged, and dysfunctional mitochondria. This process is believed to be a mitochondrial quality control system crucial for intracellular homeostasis. Recently, researchers developed a range of methods to induce mitophagy and a variety of assays to monitor this process. With these new methods, the research on mitophagy has been developed rapidly. In particular, some key receptors and regulatory factors in fungi have been identified, which provides a basis for further understanding of the mechanism of this process. Although it has been studied extensively in the model yeast Saccharomyces cerevisiae, mitophagy in pathogenic fungi remains poorly understood. However recent studies have shown that mitophagy is involved in the regulation of pathogenicity of pathogenic fungi, which greatly increases the importance of mitophagy. Therefore, it is necessary to review the current research on mitophagy in order to provide an accurate understanding of mitophagy and promote mitophagy research in the pathogenic fungi.

Isolation and Identification of Pathogenic Fungi in Kiwifruit during the Storage Period

[Objectives]The paper was to identify the pathogenic species of postharvest diseases of kiwifruit.[Methods]The pathogenic fungi were isolated from diseased kiwifruits during the storage period,and cultured to observe their culture traits and morphological characteristics.Molecular biological identification and pathogenicity test were carried out to confirm the main pathogens.[Results]There were 7 species of pathogenic fungi causing kiwifruit diseases during the storage period,including Alternaria spp.,Botryosphaeria dothidea,Phomopsis/Diaporthe spp.,Pestalotiopsis sp.,Pseudocercospora sp.,Colletotrichum sp.,and Botrytis cinerea.[Conclusions]The research will provide a scientific basis for the prevention and control of postharvest diseases of kiwifruit.

Isolation and Identification of Pathogenic Fungi Causing Decayin Luotian Chestnut during Late Storage Period and Research on Pathogenicity

In order to explore moldy mechanism of chestnut from Luotian County in storage process,the strains of pathogenic fungi were isolated from chestnuts after storage at room temperature for 70d.Six genera of fungi were found in chestnut through experimental identification,which were Ozoniumsp.,Fusarium sp.,Aspergillus sp.,Penicilliumsp.,Rhiopus sp.and Stachybotrys sp.,respectively.The re-inoculation tests had been conducted on pathogenic fungi whose isolating rate was greater than 10%.The result showed that the rest genera of fungi generally had no pathogenicity except Penicilliumsp.could infect non-injured chestnut with a lower moldy rate and lighter symptoms;but the moldy rate of strains was above 60% in injured inoculation and they showed heavy symptoms,among which the moldy rate of Ozoniumsp.and Aspergillus sp.were higher than 80%.The experimental results showed that injured chestnut were more likely to decay.Ozoniumsp.and Aspergillus sp.were important pathogenic fungi causing decay during storage process of chestnut.

Plant growth-promoting properties and anti-fungal activity of endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta in arid lands

Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.

Effect of Lanthanum on Mycelium Growth and Some Pathogenic Factors

Three soil-transmitted pathogenic fungi including Rhizoctonia solani, Fusarium solani, and Pythium sp. were selected to investigate the effect of lanthanum on their growth and the pathogenic enzymes using liquid culture. Variance analysis shows significant differences among treatments with different concentrations of lanthanum （Rhizoctonia solani F = 6.75 〉 F0.01= 5.99; Fusarium solani F = 18.1 〉 F0.01 = 5.99, Pythium sp. F = 23.29 〉 F0.01 = 5.99）. The inhibitory effect of lanthanum on pathogenic fungi increased with an increase in La concentration. The activities of the three pathogenic enzymes per gram mycelium were promoted remarkably. However, the quantity or the activities of the total enzymes were inhibited because of the strong inhibition of mycelium growth by lanthanum. Meanwhile, the effect of lanthanum on toxins of pathogenic fungi were studied using the seed germination experiment. Toxins of pathogenic fungi are influenced by lanthanum and the virulence decreases significantly with the increase of lanthanum concentration.

Lipopeptide Antibiotics Produced by the Engineered Strain Bacillus subtilis GEB3 and Detection of Its Bioactivity

MALDI-TOF-MS technology was used for identification of lipopeptide antibiotics producedby GEB3 strain, a derivative of Bacillus subtilis 168 which was transformed by lpaB3gene. The result showed GEB3 only produced lipopeptide antibiotic surfactin. The analysisby LC-MS demonstrated that GEB3 produced standard surfactin isoforms with side chainlengths of 13,14 and 15 carbon atoms. The bioactivity detection of surfactin indicatedthat the surfactin produced by GEB3 had inhibition effect on plant pathogens Rhizoctoniasolani and Pyricularia oryzae.

Identification of candidate soil microbes responsible for small-scale heterogeneity in strawberry plant vigour

Studies were conducted to identify candidate soil microbes responsible for observed differences in strawberry vigour at a small spatial scale, which was not associated with visual disease symptoms. Samples were obtained from the soils close to the rhizosphere of ‘big＇ and ‘small＇ plants from small plots which exhibited large local heterogeneity in plant vigour. A metabarcoding approach was used to profile bacterial and fungal compositions, using two primer pairs for 16 S ribosomal RNA genes（16S r DNA） and one for the fungal internal transcribed spacer（ITS） region. Of the two 16 S r DNA primer sets, the 341F/805 R resulted in sequences of better quality. A total 28 operational taxonomic units（OTUs） had differential relative abundance between samples from ‘big＇ and ‘small＇ plants. However, plausible biological explanation was only possible for three fungal OTUs. Two were possible phytopathogens： Verticillium spp. and Alternaria alternata although the latter has never been considered as a main pathogen of strawberry in the UK. For samples from ‘small＇ plants, the abundance of these OTUs was much greater than from ‘big＇ plants. The opposite was true for a mycorrhizal OTU. These results suggest that soil microbes related to crop production can be identified using metabarcoding technique. Further research is needed to assess whether A. alternata and Verticillium spp. could affect strawberry growth in the field.

Antifungal Activities of Commercial Rice Wine Extracts of Taiwan Residents Allium fistulosum

Antifungal activities of the commercial rice wine extracts of Allium fistulosum were analyzed. Antifungal activities were tested against 7 pathogenic fungi by using agar disc diffusion and tube dilution tests. The results show that the commercial rice wine extracts of Allium fistulosum have strong antifungal activity against Aspergillus brasiliensis ATCC 16404, Candida albicans ATCC 10231, Microsporumcanis ATCC 36299, M. gypseum ATCC 24102, Trichophyton mentagrophytes ATCC 9533, T. rubrum ATCC 28188, and T. tonsurans ATCC 28942. The commercial rice wine extracts of different A. fistulosum parts were found to exhibit significant antifungal activities with the minimal inhibitory concentration (MIC) in the range of 0.2 - 1.0 mg/mL. The antifungal activity of the extracts of different A. fistulosum parts was in the order of AFS (stem) > AFI (plant body) > AFL (leaf) > AFR (root).

Culturable plant pathogenic fungi associated with sugarcane in southern China

Sugarcane(Saccharum officinarum)is one of the oldest crops cultivated by mankind.Numerous fungal taxa have been reported from this host,although most were not identified beyond genus level.In this study,we explored 31 sampling sites in Guangxi and Guangdong Provinces(China),and collected 370 diseased samples from leaves and roots of sugarcane,from which 762 strains were isolated.Our preliminary analysis based on internal transcribed spacer(ITS)sequences suggested that these isolates belonged to 143 species in 51 genera,but we could not assign 129 strains.Bipolaris,Chaetomium,Curvularia,Phoma and Nigrospora represented the top five most common genera identified,while 27 rare genera comprised only one identified species.In this study,we chose above mentioned common genera for in-depth morphological observations and multi-locus analyses,in order to identify these strains to species level.In this paper,we described one new genus,32 new species,and reported 19 new records for China and the asexual morph of Chaetomium olivaceum.Hitherto,this is the most comprehensive study with molecular identification and illustration of fungi associated with sugarcane,which greatly improves our understanding of culturable mycota associated with this host.

IN VITRO ACTIVITY OF EXTRACTS OF FIVE MEDICINAL PLANT SPECIES ON PLANT PATHOGENIC FUNGI

The antifungal effectiveness of extracts of five medicinal plant species was determined.The inhibitory activity of extracts of Eucalyptus tereticornis,Xanthium sibiricum,Artemisia argyi,Tupistra chinensis and Pyrola calliantha were evaluated against the mycelial growth of the plant pathogenic fungi Aspergillus niger,Botrytis cinerea,Penicillium digitatum,P.expansum,P.italicum and Rhizopus stolonifer.All plant extracts were prepared at 60°C using solvents(either water,50%ethanol(v/v),95%ethanol(v/v),ethyl acetate or petroleum ether).Fungicidal effects of all plants tested were confirmed.Different extracts from the same plant species gave different degrees of inhibition.All aqueous extracts had weak or no activity on all fungi tested.Ethyl acetate and 95%ethanol extracts from T.chinensis rhizomes gave greater inhibition and a broader spectrum inhibition than the other extracts.T.chinensis may have potential as a new natural fungicide and may be used for the preservation of agricultural and forestry products such as fruits and vegetables.

陕西省猕猴桃黑斑病病原菌鉴定

‘翠香猕猴桃’属美味猕猴桃品系,具有早熟优质、味道香甜等优点,是陕西省周至县、鄠邑区、眉县等猕猴桃主产区特有的主栽品种[1]。2013年起,陕西周至‘翠香猕猴桃’果园连年发生黑斑病,平均病园率达85.8%,病果率达48.5%以上[2]。该病在果实生长后期呈现黑色病斑症状并在低温贮藏期引起果实腐烂,严重制约了猕猴桃产业的发展。‘翠香猕猴桃’黑斑病病原菌种类、形成机理尚不明确。本研究针对该病发生情况进行田间调查和病原菌分离.

Soil fungal community is more sensitive to nitrogen deposition than increased rainfall in a mixed deciduous forest of China

Nitrogen(N)deposition and intensified rainfall can strongly affect soil microbial community,but compared with available studies on bacteria,those on soil fungi are quite limited.Here we carried out a field experiment in a mixed deciduous forest of China to study the influences of increased N deposition and rainfall on soil fungi by using quantitative PCR and high-throughput sequencing method.The results demonstrated that(1)N addition significantly increased fungal abundance and alpha diversity(richness,Shannon index and Invsimpson index),changed fungal community composition at OTU level,and marginally increased the relative abundance of Ascomycota and Zygomycota,while water addition showed no remarkable effects on fungal abundance,biodiversity and community composition.(2)N addition significantly increased the richness of saprotrophic fungi and pathogenic fungi,and the relative abundance of saprotrophic fungi,but water addition only slightly increased the abundance of pathogenic fungi.(3)Fungal composition dissimilarity closely correlated with the disparity of soil parameters as a whole.Soil NH_(4)^(+)-N exhibited strong positive correlation with the richness of pathogenic fungi and mycorrhizal fungi,while both soil moisture and NH_(4)^(+)-N tightly correlated with soil fungal abundance and alpha diversity indices.We concluded that in this N-limited but non-water-limited forest ecosystem,N deposition posed stronger effects on soil fungi than increased rainfall,partially mediated by changes in soil properties.