한국균학회소식:학술대회논문집
The Korean Society of Mycology (KSM)
- 기타
Domain
- Life Science > Phylogenetics/Ecology/Environmentalbiology
2015.05a
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Rice blast fungus, Magnaporthe oryzae, is the most destructive pathogen of rice in the world. This fungus has a biotrophic phase early in infection and switches to a necrotrophic lifestyle after host cell death. During the biotrophic phase, the fungus competes with host for nutrients and oxygen. Continuous uptake of oxygen is essential for successful establishment of blast disease of this pathogen. Here, we report transcriptional responses of the fungus to oxygen limitation. Transcriptome analysis using RNA-Seq identified 1,047 up-regulated genes in response to hypoxia. Those genes were involved in mycelial development, sterol biosynthesis, and metal ion transport based on hierarchical GO terms and well-conserved among three different fungal species. In addition, null mutants of three hypoxia-responsive genes were generated and tested for their roles on fungal development and pathogenicity. The mutants for a sterol regulatory element-binding protein gene, MoSRE1, and C4 methyl sterol oxidase gene, ERG25, exhibited increased sensitivity to hypoxia-mimetic agent, increased conidiation, and delayed invasive growth within host cells, suggesting important roles in fungal development. However, such defects did not cause any significant decrease in disease severity. The other null mutant for alcohol dehydrogenase gene, MoADH1, showed no defect in the hypoxia-mimic condition and fungal development. Taken together, this comprehensive transcriptional profiling in response to a hypoxia condition with experimental validations would provide new insights on fungal development and pathogenicity in plant pathogenic fungi.
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Fungi are of particular interest due to their capacity to produce an extensive array of secondary metabolites. While many secondary metabolites have no known functions to the producing fungal organisms, these metabolites have tremendous importance to humans with beneficial (e.g., antibiotics) or detrimental (e.g., mycotoxins) properties. In this study, two important filamentous fungi, Fusarium verticillioides and Mycosphaerella graminicola were selected as target species and the genes regulatory functions on the biosynthesis of secondary metabolisms were studied. Functional genomics including forward and reverse genetics, and proteomics were utilized to better understand the complex secondary metabolism regulations in both F. verticillioides and M. graminicola. Identified genes in either F. verticillioides or M. graminicola background were CPP1 (a putative protein phosphatase gene), GAC1 (encoding a GTPase activating protein), MCC1(encoding c-type cyclin), and the velvet gene, MVE1. Our data suggest that there are diverse regulatory genes on fungal secondary metabolites with distinct or overlapping functional roles.
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Chung, Dawoon;Barker, Bridget M.;Carey, Charles C.;Merriman, Brittney;Werner, Ernst R.;Lechner, Beatrix E.;Dhingra, Sourabh;Cheng, Chao;Xu, Wenjie;Blosser, Sara J.;Morohashi, Kengo;Mazurie, Aurelien;Mitchell, Thomas K.;Haas, Hubertus;Mitchell, Aaron P.;Cramer, Robert A. 15
Aspergillus fumigatus is a major cause of invasive aspergillosis (IA), a significant health issue worldwide with high mortality rates up to 95%. Our lab is interested in how A. fumigatus adapts to low oxygen conditions 'hypoxia', which is one of the important host microenvironments. A. fumigatus SrbA is a basic helix-loop-helix (bHLH) transcriptional regulator and belongs to sterol regulatory element binding protein (SREBP) family members. Loss of SrbA completely blocks growth in hypoxia and results in avirulence in murine models of IA suggesting an essential role of SrbA in hypoxia adaptation and virulence in A. fumigatus. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) with A. fumigatus wild type using a SrbA specific antibody, and 97 genes were revealed as SrbA direct targets. One of the 'SrbA regulons' (AFUB_099590) was a putative bHLH transcriptional regulator whose sequence contained a characteristic tyrosine substitution in the basic portion of the bHLH domain of SREBPs. Therefore, we designated AFUB_099590 SrbB. Further characterization of SrbB demonstrated that SrbB is important for radial growth, biomass production, and biosynthesis of heme intermediates in hypoxia and virulence in A. fumigatus. A series of quantitative real time PCR showed that transcription of several SrbA regulons is coordinately regulated by two SREBPs, SrbA and SrbB in hypoxia. This suggests that SrbA and SrbB have both dependent and independent functions in regulation of genes responsible for hypoxia adaptation in A. fumigatus. Together, our data provide new insights into complicated roles of SREBPs in adaptation of host environments and virulence in pathogenic fungi. -
The term of Mushrooms means to spread like the April showers. After 18th century, the mycelium and spores of mushrooms were observed by microscope and then was denominated as fungi. About one hundred thousand species of mushrooms in appearance were worldly reported, and in Korea about four thousand species of mushrooms are estimated. In Korea, total of one thousand nine hundred one species of mushrooms have been recorded. Mushrooms belonging to the group of organisms called fungi, which must obtain their food from living plants or animals or from their remains after death. A large number of mushrooms grow in association with the roots of trees and other woody plants, called mycorrhizal fungi, both mushrooms and plants require this relationship for growth and development. And also many Mushrooms are saprobic, living on decayed various fallen leaves, twigs, trees and vegetable remains and etc. some of these million of spores settles on the proper habitat, these spores germinates and grows into a mass of threads, then a mycelium. This is the vegetable part of the mushrooms, what we call mushrooms are the carpophores, all the characteristics of the morphological features are appropriately used to identify species of mushrooms. Recently, identification and classification of mushrooms are newly confirmed by molecular analysis. In 2013, One thousand nine hundred one species of mushrooms in "List of Mushrooms in Korea" which published by the Korean Society of Mycology were recorded. Total of 238species, 107genera, 40families, 13orders, 6Classes belong to phylum Ascomycota. Total of 1,663species, 403genera 81families, 18orders, 7classes belong to phylum Basidiomycota.
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Endophytic fungi are microorganisms inhabiting living plant tissues without causing apparent harm to the host. They are drawing increasing attention due to their ability to produce various bioactive compounds as well as their effects on host growth and resistance to biotic and abiotic stresses. As a first step to assess biodiversity of plant associated fungi in Korea and the following evaluation on diverse biological activities, we are collecting endophytic fungi from plant in wild followed by systematic long-term storage in liquid nitrogen. Molecular identification using ITS sequences was also incorporated for pure culture by hyphal tip isolation. As of April 2015, about 1,400 fungal strains had been isolated from about 170 plant taxa. Fungal isolates belonging to Pleosporales, Diaporthales, Glomerellales, Hypocreales, and Xylariales were the most abundant. These collections are being used for several complementary researches, including screening of isolates with novel bioactive compounds or conferring drought stress resistance, phylogenetic and genomic study. Genome sequencing was performed for 3 isolates, one Xylaria sp. strain JS573 producing griseofulvin, an antifungal compound, and two Fusarium spp. strains JS626 and JS1030, which are assumed to be new species found in Korea. More detailed analysis on these genomes will be presented. These collections and genome informations will serve as invaluable resources for identifying novel bioactive materials in addition to expand our knowledge on fungal biodiversity.
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Plasmodiophora brassicae is a major disease threat for Brassica oil and vegetable crop production worldwide. The causal agent is a Plasmodiophorid, which are obligate biotrophic plant-pathogenic protists in the Rhizarian kingdom. Although the Plasmodiophorids include other important agricultural pathogens such as Polymyxa betae, Spongospora subterranea, their biology remains poorly understood due to their intracellular biotrophic life style. I will present the assembled and annotated genome of P. brassicae, with insights into developmental stage-specific. We provide the first genomic data for pathogenic Rhizaria. The exploitation of the life stage specific transcripts will shed light in the understanding of the life cycle at a molecular basis, which will in the long run help to understand and control club root disease. Our data also fill an important gap for the understanding of the eukaryotic tree of life, since this is only the third genome of the eukaryotic kingdom of Rhizaria.
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Yahaya, Nazariyah;Malinowski, Robert;Burrell, Mike;Walker, Heather;Petriacq, Pierre;Rolfe, Stephen 27
Clubroot (Plasmodiophora brassicae) is a serious agricultural problem affecting Brassica crop production worldwide. It also infects the model plant Arabidopsis thaliana. During infection, this biotrophic pathogen manipulates the development and metabolism of its host leading to the development of galls in the root and hypocotyl. In turn, its own development is strongly influenced by the host. The aim of this study is to investigate the metabolism of clubroot-infected plants using a combination of transcriptomic and metabolomic approaches. We have used direct injection mass spectrometry to obtain a metabolic fingerprint of when changes in the metabolome occur and linked this with changes in host and pathogen gene expression. We have identified alterations in carbohydrate metabolism that occur during P. brassicae infection of A. thaliana plants. Transcriptomic analysis showed that host genes associated with sugar transport and metabolism were induced during gall formation and that the pathogen also expresses genes associated with these processes. We have examined the impact of inactivating host sucrose synthase, cytosolic invertase and sugar permeases on gall formation, identifying host genes that are required for gall formation. We have also explored how sugar status is changed in root tissue, developing and mature leaf during infection of wild type and mutant plants. -
New Classification of Plasmodiophora brassicae Races Using Differential Genotypes of Chinese CabbageClubroot disease caused by Plasmodiophora brassicae induces severe losses of cruciferous vegetables worldwide. To control clubroot of Chinese cabbage, many CR (clubroot resistance) F1 hybrid cultivars have been bred and released in Korea, China and Japan. In this study, we determined the race of P. brassicae 12 field isolates, which collected from 10 regions in Korea, using Williams' differential varieties including two cabbage ('Jersey Queen', 'Badger Shipper') and two rutabaga ('Laurentian', 'Whilhelmsburger'). By Williams' differential varieties, 12 clubroot pathogens were assigned into one (GN2), two (HS and YC), two (HN1 and HN2), three (DJ, KS and SS) and four (GS, GN1, JS and PC) isolates for races 1, 2, 4, 5 and 9, respectively. In addition, the degree of resistance of 45 CR cultivars that were from Korea, China and Japan was tested with the 12 isolates. The 45 CR cultivars of Chinese cabbage were differentiated into three genotypes according to their resistance responses. Even though the 12 P. brassicae isolates were same race by Williams' differential varieties, three CR genotypes showed different resistance response to the isolates. These results indicate that races of P. brassicae by Williams' differentials were not related with resistance of CR cultivars, and three CR genotypes represented qualitative resistance to the P. brassicae isolates. CR genotype I including 'CR-Cheongrok' showed resistance to GN1, GN2, JS, GS, HS, DJ and KS isolates and susceptibility to YC, PC, HN1, HN2 and SS isolates. And CR genotype II such as 'Hangkunjongbyungdaebaekchae' was resistant to GN1, GN2, JS, GS, HS, YC, PC and HN1 and susceptible to DJ, KS, SS and HN2. CR genotype III including 'Chunhajangkun' and 'Akimeki' represented resistance to 10 isolates except for SS and HN2 isolates. Based on these results, we selected 'CR-Cheongrok', 'Hangkunjongbyungdaebaekchae', and 'Chunhajangkun' as a representative cultivar of three CR genotypes and 'Norangkimjang' as a susceptible cultivar. Furthermore, we investigated the resistance of 15 lines of Chinese cabbage, which were provided by seed companies, to 11 isolates except for HN1 of P. brassicae. The results showed that three lines were susceptible to all the tested isolates, whereas five, four, and three lines represented the similar responses corresponding to the CR genotypes I, II, and III, respectively; there is no line of Chinese cabbage showing different resistance patterns compared to three CR genotypes. In particular, line 'SS001' showing resistance responses of CR genotype II was a parent of 'Saerona' that have been commercialized as a CR
$F_1$ cultivar of Chinese cabbage. Together, we divided 12 isolates of P. brassicae into 4 races, designated by wild type, mutant type 1, mutant type 2, and mutant type 3. Wild type including GN1, GN2, JS, GS, and HS isolates of P. brassicae was not able to infect all the cultivars of three CR genotypes, whereas, mutant type 3 such as SS and HN2 isolates developed severe clubroot disease on all the CR genotype cultivars. To mutant type 1 including DJ and KS isolates, CR genotypes I, II and III were resistant, susceptible and resistant, respectively. In contrast, to mutant type 2 including YC, PS, and HN1 isolates, CR genotypes I, II and III showed susceptibility, resistance and resistance, respectively. Taken together, our results provide the extended knowledge of classification of P. brassicae races, which is useful information for the breeding of resistant crops, with a suggestion that 'Norangkimjang', 'CR-Cheongrok', 'Saerona' and 'Chunhajangkun' cultivars of Chinese cabbage could be used as new race differentials of P. brassicae for clubroot disease assay. -
Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.
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Clubroot disease is the major threat to the production of Chinese cabbage (Brassica rapa L.) in Japan. Although the breeding of the clubtoot resistant (CR) cultivars is one of the most efficient ways to control this disease, the CR cultivars do not always have effects due to the breakdown of resistance. Therefore, it is necessary to develop the breeding strategy to accumulate multiple CR genes in a single cultivar effectively. We have identified two incomplete dominant CR loci, Crr1 and Crr2, which are originated from the European CR turnip Siloga. To investigate the effectiveness of marker-assisted selection (MAS) for CR breeding, the inbred line with Crr1 and Crr2 was crossed with parental lines of the existing CR
$F_1$ cultivar of Chinese cabbage, followed by 5 times of MAS and backcrossing. The$F_1$ derived from a cross between the resulting parental lines improved the clubroot resistance as expected and had the same morphological characters as the original$F_1$ cultivar. We have shown that the Crr1 locus comprised two loci: Crr1a, which by itself conferred resistance to the mild isolate; and Crr1b, which had a minor effect, but was not required for Crr1a-mediated resistance. Further genetic analysis suggested that Crr1b was necessary to acquire resistance to the more virulent isolate in combination with Crr2. Molecular characterization of Crr1a encoding TIR-NB-LRR class of R protein revealed that there were at least 4 alleles in Japanese CR cultivars of Chinese cabbage. PCR analysis with Crr1a-specific markers demonstrated that the functional alleles were predicted to be present in European CR turnips, Debra and 77b besides Siloga, whereas rarely in Japanese CR cultivars, indicating that Crr1a is an useful source to improve the resistance of Chinese cabbage cultivars. -
Kimchi cabbage (Chinese cabbage), radish and Cabbage are major Brassicaceae vegetables in Korea. Especially, we can easily develop whole plant from one microspore in Kimchi cabbage. To develop clubroot resistant doubled-haploid (DH) inbred lines, we pollinated a clubroot resistant turnip of 'IT 033820' with a Kimchi cabbage (Chinese cabbage) inbred of 'BP 079'. More than 85 DH inbred lines were developed from this combination. We screened about 400 materials including these DH inbred lines, commercial cultivars and breeding materials during 3 years using hydroponic system after inoculating single spore isolation race 4(SSI-04) inoculate. One inbred line derived from this combination selected as clubroot resistant and registered as 'Wonkyo20036ho'. We inoculated 26 DH inbred lines derived from 'Zoong-baek 2ho' using SSI-4, the percent of resistant plants varied from 0 to 83%. However the horticultural traits of highly resistant DH inbred line was poor. Thus we selected one DH line showing 77% resistant with yellow inner leaf and maid good head, was registered as 'Wonkyo20034ho'. Another DH inbred line derived from Korean variety of 'Wol-dong' showing 86% resistant was registered as 'Wonkyo20037ho'. Other DH inbred lines were derived from Chinese cultivar of 'Choon-hi-go-hang-wang' and 'Hwang-shim-zo48' showed 80 and 71% resistant, respectively, was also selected for registration. Even though DH inbred lines derived from turnip showed highly resistant to SSI-04 and provincial inoculate, they showed poor characteristics in horticultural traits. However, commercial seed companies showed interesting for adapting these DH inbred lines in commercial breeding.
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Throughout the world, clubroot disease is one of the most damaging diseases affecting Brassica oleracea. In order to perform QTL analysis of CR (clubroot resistance) loci in B. oleracea, we constructed a map, and analyzed CR-QTLs using the mean phenotypes of F3 progenies from the cross of a resistant double-haploid cabbage line (Anju) with a susceptible double-haploid broccoli line (GC). We identified one major QTL, pb-Bo(Anju)1 in C2 from Anju and four minor QTLs; pb-Bo(GC)1 in O5 from GC, pb-Bo(Anju)2, -3, -4 in C2, C3, and C7 from Anju, respectively. Additionally, we found that the accumulation of Pb-Bo(Anju)1 allele and the minor CR-QTLs is essential for resistance against various six isolates. Our finding markers closely linked to the CR-QTLs will help marker-assisted selection for CR. At present, we are undergoing toward map-based cloning for Pb-Bo(Anju)1 gene. The preliminary experiment delimited Pb-Bo(Anju)1 locus, encompassing among 450kB.
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Yuan, Yu-Xiang;Wei, Xiao-Chun;Zhang, Qiang;Zhao, Yan-Yan;Jiang, Wu-Sheng;Yao, Qiu-Ju;Wang, Zhi-Yong;Zhang, Ying;Tan, Yafei;Li, Yang;Xu, Qian;Zhang, Xiao-Wei 41
BSA-seq technologies, combined Bulked Segregant Analysis (BSA) and Next-Generation Sequencing (NGS), are making it faster and more efficient to establish the association of agronomic traits with molecular markers or candidate genes, which is the requirement for marker-assisted selection in molecular breeding. Clubroot disease, caused by Plasmodiophora brassicae, is a serious threat to Brassica crops. Even we have breed new clubroot resistant varieties of Chinese cabbage (B. rapa ssp. pekinesis), the underlying genetic mechanism is unclear. In this study, an$F_2$ population of 340 plants were inoculated with P. brassicae from Xinye (Pathotype 2 on the differentials of Williams). Resistance phenotype segregation ratio for the populations fit a 3:1 (R:S) segregation model, consistent with a single dominant gene model. Super-BSA, using re-sequencing the parents, extremely R and S DNA pools with each 50 plants, revealed 3 potential candidate regions on the chromosome A03, with the most significant region falling between 24.30 Mb and 24.75 Mb. A linkage map with 31 markers in this region was constructed with several closely linked markers identified. A Major QTL for clubroot resistance, CRq, which was identified with the peak LOD score at 169.3, explaining 89.9% of the phenotypic variation. And we developed a new co-segregated InDel marker BrQ-2. Joint BSA-seq and traditional QTL analysis delimited CRq to an 250 kb genomic region, where four TIR-NBS-LRR genes (Bra019409, Bra019410, Bra019412 and Bra019413) clustered. The CR gene CRq and closely linked markers will be highly useful for breeding new resistant Chinese cabbage cultivars. -
Plasmodiophora brassicae, the causal agent of clubroot disease, does the most serious damage to the Brassica crops. The limited control approaches make that the identification of clubroot resistance (CR) is more important for developing CR cultivars of the Brassica crops. So far, 8 CR loci were mapped. However, the variation of P. brassicae leads to the rapid erosion of its resistance. To identify novel CR genes, we employed three mapping population, derived from crosses between Chinese cabbage and turnip inbred lines (
$59-1{\times}ECD04$ and$BJN3-1{\times}Siloga$ ) or between Chinese cabbage inbred lines ($BJN3-1{\times}85-I-II$ ), to perform QTL analysis. Totally, 8 CR loci were indentified and showed race-specific resistance. Physical mapping of these 8 loci suggested that 4 were located previously mapped position, indicating they might be the same allele or different alleles of the same genes. Other 4 loci were found to be novel. Further, CR near isogenic line carrying each CR locus was developed based on the marker assisted selection. Verification of these CR loci was underway. Identification of these novel CR genes would facilitate to breed broad-spectrum and durable CR cultivars of B. rapa by pyramiding strategies. -
Clubroot disease of crucifers has occurred since 1957. It has spread to the whole China, especially in the southwest and nourtheast where it causes 30-80% loss in some fields. The disease has being expanded in the recent years as seeds are imported and the floating seedling system practices. For its effective control, the Ministry of Agriculture of China set up a program in 2010 and a research team led by Dr. Yueqiu HE, Yunnan Agricultural University. The team includes 20 main reseachers of 11 universities and 5 institutions. After 5 years, the team has made a lot of progresses in disease occurrence regulation, resources collection, resistance identification and breeding, biological agent exploration, formulation, chemicals evaluation, and control strategy. About 1200 collections of local and commercial crucifers were identified in the field and by artificiall inoculation in the laboratories, 10 resistant cultivars were breeded including 7 Chinese cabbages and 3 cabbages. More than 800 antagostic strains were isolated including bacteria, stretomyces and fungi. Around 100 chemicals were evaluated in the field and greenhouse based on its control effect, among them, 6 showed high control effect, especially fluazinam and cyazofamid could control about 80% the disease. However, fluzinam has negative effect on soil microbes. Clubroot disease could not be controlled by bioagents and chemicals once when the pathogen Plasmodiophora brassicae infected its hosts and set up the parasitic relationship. We found the earlier the pathogent infected its host, the severer the disease was. Therefore, early control was the most effective. For Chinese cabbage, all controlling measures should be taken in the early 30 days because the new infection could not cause severe symptom after 30 days of seeding. For example, a biocontrol agent, Bacillus subtilis Strain XF-1 could control the disease 70%-85% averagely when it mixed with seedling substrate and was drenching 3 times after transplanting, i.e. immediately, 7 days, 14 days. XF-1 has been deeply researched in control mechanisms, its genome, and development and application of biocontrol formulate. It could produce antagonistic protein, enzyme, antibiotics and IAA, which promoted rhizogenesis and growth. Its The genome was sequenced by Illumina/Solexa Genome Analyzer to assembled into 20 scaffolds then the gaps between scaffolds were filled by long fragment PCR amplification to obtain complet genmone with 4,061,186 bp in size. The whole genome was found to have 43.8% GC, 108 tandem repeats with an average of 2.65 copies and 84 transposons. The CDSs were predicted as 3,853 in which 112 CDSs were predicted to secondary metabolite biosynthesis, transport and catabolism. Among those, five NRPS/PKS giant gene clusters being responsible for the biosynthesis of polyketide (pksABCDEFHJLMNRS in size 72.9 kb), surfactin(srfABCD, 26.148 kb, bacilysin(bacABCDE 5.903 kb), bacillibactin(dhbABCEF, 11.774 kb) and fengycin(ppsABCDE, 37.799 kb) have high homolgous to fuction confirmed biosynthesis gene in other strain. Moreover, there are many of key regulatory genes for secondary metabolites from XF-1, such as comABPQKX Z, degQ, sfp, yczE, degU, ycxABCD and ywfG. were also predicted. Therefore, XF-1 has potential of biosynthesis for secondary metabolites surfactin, fengycin, bacillibactin, bacilysin and Bacillaene. Thirty two compounds were detected from cell extracts of XF-1 by MALDI-TOF-MS, including one Macrolactin (m/z 441.06), two fusaricidin (m/z 850.493 and 968.515), one circulocin (m/z 852.509), nine surfactin (m/z 1044.656~1102.652), five iturin (m/z 1096.631~1150.57) and forty fengycin (m/z 1449.79~1543.805). The top three compositions types (contening 56.67% of total extract) are surfactin, iturin and fengycin, in which the most abundant is the surfactin type composition 30.37% of total extract and in second place is the fengycin with 23.28% content with rich diversity of chemical structure, and the smallest one is the iturin with 3.02% content. Moreover, the same main compositions were detected in Bacillus sp.355 which is also a good effects biocontol bacterial for controlling the clubroot of crucifer. Wherefore those compounds surfactin, iturin and fengycin maybe the main active compositions of XF-1 against P. brassicae. Twenty one fengycin type compounds were evaluate by LC-ESI-MS/MS with antifungal activities, including fengycin A
$C_{16{\sim}C19}$ , fengycin B$C_{14{\sim}C17}$ , fengycin C$C_{15{\sim}C18}$ , fengycin D$C_{15{\sim}C18}$ and fengycin S$C_{15{\sim}C18}$ . Furthermore, one novel compound was identified as Dehydroxyfengycin$C_{17}$ according its MS, 1D and 2D NMR spectral data, which molecular weight is 1488.8480 Da and formula$C_{75}H_{116}N_{12}O_{19}$ . The fengycin type compounds (FTCPs$250{\mu}g/mL$ ) were used to treat the resting spores of P. brassicae ($10^7/mL$ ) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A260) and at 280 nm (A280) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be lyzed by the FTCPs of XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol. In the five selected medium MOLP, PSA, LB, Landy and LD, the most suitable for growth of strain medium is MOLP, and the least for strains longevity is the Landy sucrose medium. However, the lipopeptide highest yield is in Landy sucrose medium. The lipopeptides in five medium were analyzed with HPLC, and the results showed that lipopeptides component were same, while their contents from B. subtilis XF-1 fermented in five medium were different. We found that it is the lipopeptides content but ingredients of XF-1 could be impacted by medium and lacking of nutrition seems promoting lipopeptides secretion from XF-1. The volatile components with inhibition fungal Cylindrocarpon spp. activity which were collect in sealed vesel were detected with metheds of HS-SPME-GC-MS in eight biocontrol Bacillus species and four positive mutant strains of XF-1 mutagenized with chemical mutagens, respectively. They have same main volatile components including pyrazine, aldehydes, oxazolidinone and sulfide which are composed of 91.62% in XF-1, in which, the most abundant is the pyrazine type composition with 47.03%, and in second place is the aldehydes with 23.84%, and the third place is oxazolidinone with 15.68%, and the smallest ones is the sulfide with 5.07%. -
Over the past decade, clubroot has emerged as a major constraint to canola (Brassica napus) production in central Alberta, Canada. The number of fields with confirmed P. brassicae infestations in Alberta has increased steadily from 12 in 2003 to nearly 2,000 in 2014. Management of clubroot on canola has focused on sanitization of field equipment, soil amendments to reduce viable pathogen populations, long rotations out of susceptible crops and cropping of resistant cultivars. Clubroot resistance is the most effective and economical method of disease mitigation, but the recent identification of isolated P. brassicae populations with novel virulence phenotypes capable of overcoming resistance in most canola cultivars highlights the variable nature and adaptability of the pathogen. Recent studies have shown slight reductions in pathogen populations through crop rotations, but much more substantial reductions in spore populations in heavily infested areas near field entrances using fumigants such as Vapam (metam-sodium) or Basamid (dazomet). Greenhouse trials showed that seedling emergence, plant height and root weight increased, while primary and secondary infection and disease severity decreased with increased Basamid dosage. However, field trials showed some phytotoxicity. Application of Vapam at rates of 0.4 to
$1.6mL\;L^{-1}$ soil resulted in 12-16 fold reductions in clubroot severity and primary and secondary infection. Vapam also was effective in reducing clubroot severity and improving canola seed yield under field conditions. These studies underscore the need for good resistance stewardship and for the integration of multiple products and practices for successful management of clubroot on canola. -
Both agriculture and local tourism of Kagoshima prefecture where is located on the south-western region of the Japanese mainland, are the important industries. Although cabbage (Brassica oleracea) has been cultivated in recent decades in Kagoshima, clubroot disease caused by Plasmodiophora brassicae had never been observed. However, the disease in cabbage was reported in four regions last couple years. Our survey showed that one region is infested severely whereas others are slightly. In the most widely infested region, the disease was also observed in turnip rape (Brassica rapa) which is grown as ornamental plants for landscape design in early spring and important tourist attraction. Consequently, both agriculture and local tourism are damaged by clubroot. The increase of clubroot incidence in this region might be caused by significant increase of cabbage production, the expansion of cropping season throughout the year and continuous turnip rape cultivation in the same fields of cabbage for almost three decades. Therefore we are trying to estimate the risk of clubroot damage cultivation throughout the year in this region. We collected five isolates of resting spores and identified them as race 3, 4 and 9 by Williams' method, and as pathotype group 3 and 4 by classification system using clubroot resistant (CR)
$F_1$ cultivars of Chinese cabbage as differential hosts as described in Hatakeyama et al.(2004). Furthermore, we found that these populations were avirulent to commercial CR cabbages. These results indicate that introduction of CR cabbage and breeding of turnip rape are the effective measures to solve our problem. -
Kong, Won-Sik;Woo, Sung-I;Jang, Kab-Yeul;Shin, Pyung-Gyun;Oh, Youn-Lee;Kim, Eun-sun;Oh, Min-Jee;Park, Young-Jin;Lee, Chang-Soo;Kim, Jong-Guk 53
Agrobacterium tumefaciens-mediated transformation(ATMT) of Flammulina velutipes was used to produce a diverse number of transformants to discover the functions of gene that is vital for its variation color, spore pattern and cellulolytic activity. Futhermore, the transformant pool will be used as a good genetic resource for studying gene functions. Agrobacterium-mediated transformation was conducted in order to generate intentional mutants of F. velutipes strain KACC42777. Then Agrobacterium tumefaciens AGL-1 harboring pBGgHg was transformed into F. velutipes. This method is use to determine the functional gene of F. velutipes. Inverse PCR was used to insert T-DNA into the tagged chromosomal DNA segments and conducting sequence analysis of the F. velutipes. But this experiment had trouble in diverse morphological mutants because of dikaryotic nature of mushroom. It needed to make monokaryotic fruiting varients which introduced genes of compatible mating types. In this study, next generation sequencing data was generated from 28 strains of Flammulina velutipes with different phenotypes using Illumina Hiseq platform. Filtered short reads were initially aligned to the reference genome (KACC42780) to construct a SNP matrix. And then we built a phylogenetic tree based on the validated SNPs. The inferred tree represented that white- and brown- fruitbody forming strains were generally separated although three brown strains, 4103, 4028, and 4195, were grouped with white ones. This topological relationship was consistently reappeared even when we used randomly selected SNPs. Group I containing 4062, 4148, and 4195 strains and group II containing 4188, 4190, and 4194 strains formed early-divergent lineages with robust nodal supports, suggesting that they are independent groups from the members in main clades. To elucidate the distinction between white-fruitbody forming strains isolated from Korea and Japan, phylogenetic analysis was performed using their SNP data with group I members as outgroup. However, no significant genetic variation was noticed in this study. A total of 28 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4210 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr01, chr04, chr07,chr11 regions were identified to be associated with white fruitbody forming. White and Brown Fruitbody strains can be used as an identification marker for F. veluipes. We can develop some molecular markers to identify colored strains and discriminate national white varieties against Japanese ones. -
Crops lack genetic resistance to most necrotrophic soil-borne pathogens and parasitic nematodes that are ubiquitous in agroecosystems worldwide. To overcome this disadvantage, plants recruit and nurture specific group of antagonistic microorganisms from the soil microbiome to defend their roots against pathogens and other pests. The best example of this microbe-based defense of roots is observed in disease-suppressive soils in which the suppressiveness is induced by continuously growing crops that are susceptible to a pathogen. Suppressive soils occur globally yet the microbial basis of most is still poorly described. Fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae is a major disease of strawberry and is naturally suppressed in Korean fields that have undergone continuous strawberry monoculture. Here we show that members of the genus Streptomyces are the specific bacterial components of the microbiome responsible for the suppressiveness that controls Fusarium wilt of strawberry. Furthermore, genome sequencing revealed that Streptomyces griseus, which produces a novel thiopetide antibiotic, is the principal species involved in the suppressiveness. Finally, chemical-genetic studies demonstrated that S. griseus antagonizes F. oxysporum by interfering with fungal cell wall synthesis. An attack by F. oxysporum initiates a defensive "cry for help" by strawberry root and the mustering of microbial defenses led by Streptomyces. These results provide a model for future studies to elucidate the basis of microbially-based defense systems and soil suppressiveness from the field to the molecular level.
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Rust is one of the most destructive diseases on economically important plants such as agricultural and horticultural crops, as well as forest trees [1]. Chemical treatment is the most effective means to control rust, but use of the chemical fungicides involves inevitable risks to human health and environment [2]. Unfortunately, biocontrol is currently impracticable for rust disease management [3]. It is necessary to exploit biocontrol agents to help prevent rust diseases. As a fundamental research for future development of biocontrol agents for rusts, biodiversity of hyperparasites occurring on rust fungi was investigated. During 2006-2010, 197 fungal isolates of the rust hyperparasites were collected and isolated from various combinations of mycohosts and plant hosts in many regions of Korea. Based on morphological and molecular data, they were identified as 8 genera and 12 species. Besides, phylogenetic relationships between the hyperparasites and related taxa were inferred. A total of 114 isolates of Pseudovirgaria were obtained from rust pustules of Phragmidium spp. and Pucciniastrum agrimoniae infecting rosaceous plants. Phylogenetic analysis using multigene sequences revealed a high level of genetic variability among many isolates of Pseudovirgaria and close correlation between the isolates and mycohosts. Only two species of Pseudovirgaria, P. hyperparasitica and P. grisea are often difficult to distinguish by their morphological similarity, but on the molecular basis they were clearly differentiated from each other. There had been no previous record of P. grisea outside Europe, but the present study has proved its presence in Korea. Among six distinct groups (five of P. hyperparasitica and one of P. grisea) within the Pseudovirgaria isolates, each lineage of P. hyperparasitica was closely associated with specific mycohosts and thus might have cospeciated with their mycohosts, which probably led to coevolution. Although P. grisea possesses a host preference for Phragmidium species occurring on Rubus, it was not specific for a mycohost. P. grisea seems to evolve in the direction of having a broad mycohost range. Seventeen isolates of Verticillium-like fungi were isolated from rust sori. Based on morphological data and DNA sequence analysis, the isolates were identified as three Lecanicillium species, viz. L. attenuatum, Lecanicillium sp. 1, Lecanicillium sp. 2, and V. epiphytum. The unidenified two species of Lecanicillium appear to be previously unknown taxa. Sixty-six isolates of miscellaneous hyphomycetes belonging to 6 species of 5 genera were obtained from pustules of rust fungi. On the basis of morphological and molecular analyses, the miscellaneous hyphomycetes growing on rusts were identified as Acrodontium crateriforme, Cladophialophora pucciniophila, Cladosporium cladosporioides, Phacellium vossianum, Ramularia coleosporii, and R. uredinicola.
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Jung, Kwang-Woo;Yang, Dong-Hoon;Maeng, Shinae;Lee, Kyung-Tae;So, Yee-Seul;Hong, Joohyeon;Choi, Jaeyoung;Byun, Hyo-Jeong;Kim, Hyelim;Bang, Soohyun;Song, Min-Hee;Lee, Jang-Won;Kim, Min Su;Kim, Seo-Young;Ji, Je-Hyun;Park, Goun;Kwon, Hyojeong;Cha, Sooyeon;Meyers, Gena Lee;Wang, Li Li;Jang, Jooyoung;Janbon, Guilhem;Adedoyin, Gloria;Kim, Taeyup;Averette, Anna K.;Heitman, Joseph;Cheong, Eunji;Lee, Yong-Hwan;Lee, Yin-Won;Bahn, Yong-Sun 59
Cryptococcus neoformans causes life-threatening meningoencephalitis in humans, but the treatment of cryptococcosis remains challenging. To develop novel therapeutic targets and approaches, signaling cascades controlling pathogenicity of C. neoformans have been extensively studied but the underlying biological regulatory circuits remain elusive, particularly due to the presence of an evolutionarily divergent set of transcription factors (TFs) in this basidiomycetous fungus. In this study, we constructed a high-quality of 322 signature-tagged gene deletion strains for 155 putative TF genes, which were previously predicted using the DNA-binding domain TF database (http://www.transcriptionfactor.org/). We tested in vivo and in vitro phenotypic traits under 32 distinct growth conditions using 322 TF gene deletion strains. At least one phenotypic trait was exhibited by 145 out of 155 TF mutants (93%) and approximately 85% of the TFs (132/155) have been functionally characterized for the first time in this study. Through high-coverage phenome analysis, we discovered myriad novel TFs that play critical roles in growth, differentiation, virulence-factor (melanin, capsule, and urease) formation, stress responses, antifungal drug resistance, and virulence. Large-scale virulence and infectivity assays in insect (Galleria mellonella) and mouse host models identified 34 novel TFs that are critical for pathogenicity. The genotypic and phenotypic data for each TF are available in the C. neoformans TF phenome database (http://tf.cryptococcus.org). In conclusion, our phenome-based functional analysis of the C. neoformans TF mutant library provides key insights into transcriptional networks of basidiomycetous fungi and ubiquitous human fungal pathogens. -
Hybrid histidine kinase is a part of two-component system that is required for various stress responses and pathogenesis of pathogenic fungi. In the present study, Tco1, a homologue of human pathogen Cryptococcus neoformans Tco1 encoding a hybrid histidine kinase, was identified in corn smut pathogen Ustilago maydis by bioinformatic analysis. To explore the role of Tco1 in the virulence of U. maydis, mutants in which the tco1 gene was partially deleted were constructed by allelic exchange. The U. maydis tco1 mutants did show unaltered growth rate on axenic medium but were unable to produce conjugation tubes and develop fuzzy filaments, resulting in impaired mating of compatible strains. The expression levels of prf1, pra1, and mfa1 which are involved in the pheromone pathway significantly decreased in the tco1 mutants. In inoculation tests to host, the tco1 mutants showed significantly reduced ability in the production of anthocyanin pigments and tumor development on maize leaves. Overall, the combined results indicated that Tco1 plays important roles in sexual development and virulence of U. maydis by regulating the expression of the genes involved in the pheromone pathway.
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Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. The rice - M. oryzae pathosystem has become a model in the study of plant - fungal interactions due to its economic importance and accumulating knowledge. During the evolutionary arms race with M. oryzae, rice plants evolved a repertoire of Resistance (R) genes to protect themselves from diseases in a gene-for-gene fashion. M. oryzae secretes a battery of small effector proteins to manipulate host functions for its successful infection, and some of them are recognized by host R proteins as avirulence effectors (AVR), which turns on strong immunity. Therefore, the analysis of interactions between AVRs and their cognate R proteins provide crucial insights into the molecular basis of plant - fungal interactions. Rice blast resistance genes Pik, Pia, Pii comprise pairs of protein-coding ORFs, Pik-1 and Pik-2, RGA4 and RGA5, Pii-1 and Pii-2, respectively. In all three cases, the paired genes are tightly linked and oriented to the opposite directions. In the AVR-Pik/Pik interaction, it has been unraveled that AVR-Pik binds to the N-terminal coiled-coil domain of Pik-1. RGA4 and RGA5 are necessary and sufficient to mediate Pia resistance and recognize the M. oryzae effectors AVR-Pia and AVR1-CO39. A domain at the C-terminus of RGA5 characterized by a heavy metal associated domain was identified as the AVR-binding domain of RGA5. Similarly, physical interactions among Pii-1, Pii-2 and AVR-Pii are being analyzed.