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1.
Treatments with conidia of Penicillium oxalicum produced in a solid‐state fermentation system were applied at similar densities (6 × 106 spores/g seedbed substrate) to tomato seedbeds in water suspensions (T1: 5 days before sowing, or T2: 7 days before transplanting; 15 days after sowing), or in mixture with the production substrate (T3: 7 days before transplanting; 15 days after sowing). Treatments T2 and T3 significantly (P = 0.05) reduced fusarium wilt of tomato in both greenhouse (artificial inoculation) (33 and 28%, respectively) and field conditions (naturally infested soils) (51 and 72%, respectively), while treatment T1 was efficient only in greenhouse (52%). Verticillium wilt disease reduction was obtained with T3 in two field experiments (56 and 46%, respectively), while T1 and T2 reduced disease only in one field experiment (52% for both T1 and T2). Treatment with conidia of P. oxalicum plus fermentation substrate (T3) resulted in better establishment of a stable and effective population of P. oxalicum in seedbed soil and rhizosphere providing populations of approx. 107 CFU/g soil before transplanting. Results indicate that it will be necessary to apply P. oxalicum at a rate of approx. 106–107 CFU/g in seedbed substrate and rhizosphere before transplanting for effective control of fusarium and verticillium wilt of tomato, and that formulation of P. oxalicum has a substantial influence on its efficacy.  相似文献   

2.
The influence of the nutrient solution pH on suppression of fusarium wilt by Pseudomonas flurescens WCS417r in carnation grown in rockwool was investigated. Experiments were conducted with carnation cultivars Lena and Pallas, susceptible and moderately resistant to fusarium wilt, respectively. WCS417r significantly reduced fusarium wilt in the susceptible cv. Lena, that was root-inoculated with Fusarium oxysporum f.sp. dianthi (Fod), at pH 7.5, but not at pH 6.5 and 5.5 This corresponded with a higher in vitro siderophore production and antagonism of Fod by WCS417r at pH 7.5 than at pH 6.5 and 5.5. Fusarium wilt in the moderately resistant cv. Pallas, however, was also significantly reduced by treatment with WCS417r at pH 5.5 This corresponded with the low influence of pH on induced resistance by WCS417r in plants of cv. Pallas that were stem-inoculated with Fod. The results indicate that the influence of pH on control of fusarium wilt of carnation by Pseudomonas fluorescens WCS417r differs between carnation cultivars that differ in their level of resistance against fusarium wilt. In susceptible cv. Lena, fusarium wilt is suppressed by antagonism by WCS417r, that is most effective at pH 7.5. In the moderately resistant cv. Pallas, fusarium wilt is suppressed by both antagonism and induced resistance by WCS417r. The latter is also effective at lower pH.  相似文献   

3.
尖孢镰孢菌古巴专化型(Fusarium oxysporum f.sp.cubense)是香蕉枯萎病的病原菌,该菌是一种土壤习居菌,了解香蕉根区土壤中真菌多样性及镰孢菌属(Fusarium)真菌所占比例,对如何减少土壤中的病原菌、预防香蕉枯萎病的发生有重要的指导意义。该文通过采集不同宿根年限的香蕉健康植株和枯萎病植株的根区土壤,利用高通量测序技术测定土壤样品中的真菌种群。结果表明:(1)同一宿根年限的香蕉植株中,健康植株根区土壤中所获的reads及OTUs数量均高于枯萎病植株,说明健康植株根区土壤的真菌多样性丰富于枯萎病植株。(2)除了一年生香蕉枯萎病植株以担子菌门(Basidiomycota)为主外,其他土壤样品中均以子囊菌门(Ascomycota)为主,其中的丛赤壳科最高相对丰度来自三年生健康植株的根区土壤(26.02%),其次是五年生的枯萎病植株根区土壤(15.56%)。(3)在丛赤壳科中,镰孢菌属在三年生健康植株土壤中的相对丰度最高(2.54%),在其他样品中的相对丰度在0.1%~0.65%之间;在镰孢菌属中,腐皮镰孢菌(Fusarium solani)的相对丰度(0~1.59%...  相似文献   

4.
As a step toward greater understanding of the genetics of verticillium wilt resistance in plants, we report the sequencing of a candidate wilt resistance gene, mVe1, from the mint diploid model species, Mentha longifolia (Lamiaceae). mVe1 is a putative homolog of tomato (Solanum lycopersicum L.) verticillium wilt (Ve) resistance genes. The mVe1 gene has a coding region of 3,051 bp. The predicted mVe1 protein contains a leucine-rich repeat domain, a common feature of plant disease resistance proteins. We compared 13 mVe1 alleles from three mint species. These alleles shared 96.2–99.6% nucleotide identity. We analyzed four M. longifolia populations segregating with respect to mVe1 alleles and wilt resistance versus susceptibility and found one association between mVe1 genotype and wilt phenotype. We conclude that mVe1 may play a role in mint verticillium wilt resistance, but variation for resistance in our segregating progenies is likely polygenic. Therefore, further investigations of mVe1 and identification of additional candidate genes are both warranted.  相似文献   

5.
Fusarium oxysporum f. sp. vasinfectum (Fov) has the potential to become the most economically significant pathogen of cotton in Australia. Although the levels of resistance present in the new commercial cultivars have improved significantly, they are still not immune and cotton breeders continue to look for additional sources of resistance. The native Australian Gossypium species represent an alternative source of resistance because they could have co-evolved with the indigenous Fov pathogens. Forty-six BC3 G. hirsutum × G. sturtianum multiple alien-chromosome-addition-line (MACAL) families were challenged with a field-derived Fov isolate (VCG-01111). The G. hirsutum parent of the hexaploid MACAL is highly susceptible to fusarium wilt; the G. sturtianum parent is strongly resistant. Twenty-two of the BC3 families showed enhanced fusarium wilt resistance relative to the susceptible G. hirsutum parent. Logistic regression identified four G. sturtianum linkage groups with a significant effect on fusarium wilt resistance: two linkage groups were associated with improved fusarium wilt resistance, while two linkage groups were associated with increased fusarium wilt susceptibility.  相似文献   

6.
Treatment with Pseudomonas putida WCS358r, a rifampicin‐resistant derivative of strain WCS358, significantly reduced fusarium wilt of carnation grown in rockwool if disease incidence was moderate, but not if disease incidence was high. Differences in disease incidence could intentionally be established by varying the inoculum density of the pathogen Fusarium oxysporum f. sp. dianthi (Fod). The effectiveness of disease suppression by WCS358r increased with decrease of inoculum density and consequently decrease of disease incidence. WCS358r and a Tn5 marked derivative of WCS358 (B243) reduced fusarium wilt of carnation most effectively if a low iron availability for the pathogen was established by adding unferrated or only partially ferrated ethylenediamine [di(o‐hydroxyphenylacetic) acid]. A Tn5 mutant of WCS358 defective in siderophore biosynthesis (JM218) did not reduce disease incidence. Siderophore production and inhibition of Fod by WCS358r in vitro decreased with increasing iron availability, supporting the more effective disease suppression by strains WCS358r and B243 at low iron availability. Siderophore‐mediated competition for iron was shown to be the mechanism of suppression of fusarium wilt of carnation by P. putida WCS358. Its effectivity was highest at a low iron availability and at a moderate disease incidence.  相似文献   

7.
Verticillium wilt is a plant vascular disease caused by the soilborne fungus Verticillium dahliae that severely limits cotton production. In a previous study, we screened Bacillus cereus YUPP-10, an efficient antagonistic bacterium, to uncover mechanisms for controlling verticillium wilt. Here, we report a novel antimicrobial cyclodextrin glycosyltransferase (CGTase) from YUPP-10. Compared to other CGTases, six different conserved domains were identified, and six mutants were constructed by gene splicing with overlap extension PCR. Functional analysis showed that domain D was important for hydrolysis activity and domains A1 and C were important for inducing disease resistance. Direct effects of recombinant CGTase on V. dahliae included reduced mycelial growth, spore germination, spore production, and microsclerotia germination. In addition, CGTase also elicited cotton's innate defence reactions. Transgenic Arabidopsis thaliana lines that overexpress CGTase showed higher resistance to verticillium wilt. Transgenic CGTase A. thaliana plants grew faster and resisted disease better. CGTase overexpression enabled a burst of reactive oxygen species production and activated pathogenesis-related gene expression, indicating that the transgenic cotton was better prepared to protect itself from infection. Our work revealed that CGTase could inhibit the growth of V. dahliae, activate innate immunity, and play a major role in the biocontrol of fungal pathogens.  相似文献   

8.
Fusarium wilt (Fusarium oxysporum Schlecht. f. sp. melongenae) is a vascular disease of eggplant (Solanum melongena L.). The objectives of this work were (1) to confirm the monogenic inheritance of fusarium wilt resistance in eggplant, (2) to identify molecular markers linked to this resistance, and (3) to develop SCAR markers from most informative markers. We report the tagging of the gene for resistance to fusarium wilt (FOM) in eggplant using SRAP, RGA, SRAP-RGA and RAPD markers. Analysis of segregation data confirmed the monogenic inheritance of resistance. DNA from F2 and BC1 populations of eggplant segregating for fusarium wilt resistance was screened with 2,316 primer combinations to detect polymorphism. Three markers were linked within 2.6 cM of the gene. The codominant SRAP marker Me8/Em5 and dominant SRAP-RGA marker Em12/GLPL2 were tightly linked to each other and mapped 1.2 cM from the resistance gene, whereas RAPD marker H12 mapped 2.6 cM from the gene and on the same side as the other two markers. The SRAP marker was converted into two dominant SCAR markers that were confirmed to be linked to the resistance gene in the F2, BC1 and F2 of BC3 generations of the same cross. These markers provide a starting point for mapping the eggplant FOM resistance gene in eggplant and for exploring the synteny between solanaceous crops for fusarium wilt resistance genes. The SCAR markers will be useful for identifying fusarium wilt-resistant genotypes in marker-assisted selection breeding programs using segregating progenies of the resistant eggplant progenitor used in this study.  相似文献   

9.
Tian J  Zhang X  Liang B  Li S  Wu Z  Wang Q  Leng C  Dong J  Wang T 《PloS one》2010,5(12):e14218

Background

Programmed cell death plays an important role in mediating plant adaptive responses to the environment such as the invasion of pathogens. Verticillium wilt, caused by the necrotrophic pathogen Verticillium dahliae, is a serious vascular disease responsible for great economic losses to cotton, but the molecular mechanisms of verticillium disease and effective, safe methods of resistance to verticillium wilt remain unexplored.

Methodology/Principal Findings

In this study, we introduced baculovirus apoptosis inhibitor genes p35 and op-iap into the genome of cotton via Agrobacterium-mediated transformation and analyzed the response of transgenic plants to verticillium wilt. Results showed that p35 and op-iap constructs were stably integrated into the cotton genome, expressed in the transgenic lines, and inherited through the T3 generation. The transgenic lines had significantly increased tolerance to verticillium wilt throughout the developmental stages. The disease index of T1–T3 generation was lower than 19, significantly (P<0.05) better than the negative control line z99668. After treatment with 250 mg/L VD-toxins for 36 hours, DNA from negative control leaves was fragmented, whereas fragmentation in the transgenic leaf DNA did not occur. The percentage of cell death in transgenic lines increased by 7.11% after 60 mg/L VD-toxin treatment, which was less than that of the negative control lines''s 21.27%. This indicates that p35 and op-iap gene expression partially protects cells from VD-toxin induced programmed cell death (PCD).

Conclusion/Significance

Verticillium dahliae can trigger plant cells to die through induction of a PCD mechanism involved in pathogenesis. This paper provides a potential strategy for engineering broad-spectrum necrotrophic disease resistance in plants.  相似文献   

10.
Three single nucleotide polymorphism (SNP) sites in which amino acids had changed were detected by sequence analysis within the leucine-rich repeat (LRR) region of the Fom-2 gene. Cleaved amplified polymorphic sequence (CAPS) and allele-specific PCR (AS-PCR) methods were employed to explore the SNP validation linked to fusarium wilt resistance in the F1 and F2 generations simultaneously. Homozygous- and heterozygous-resistant genotypes and homozygous-susceptible genotype could be clearly distinguished using the CAPS method, and three detected SNP sites were observed to be linked to fusarium wilt resistance, with a segregation ratio of 1:2:1 in the F2 generation. In addition, heterozygous-resistant and homozygous-susceptible genotypes could be clearly distinguished in the F1 generation using the AS-PCR method, showing a 3:1 segregation in terms of resistant and susceptible genotypes in the F2 generation. We therefore developed SNP-based functional markers (FMs) and identified some melon germplasm resistant to fusarium wilt by FM analysis within melon species. In conclusion, the SNP-based FMs originating from the SNP site of the Fom-2 LRR region were determined to be linked to fusarium wilt resistance and showed promise in the enhancement of breeding in melon.  相似文献   

11.
PevD1, a novel protein elicitor from the pathogenic cotton verticillium wilt fungus, Verticillium dahliae, induced a hypersensitive response in tobacco plants. In this paper, the elicitor was purified and analyzed using de novo sequencing. The protein-encoding pevD1 gene consists of a 468-bp open reading frame that produces a polypeptide of 155 amino acids, with a theoretical molecular weight of 16.23 kDa. The sequence of elicitor protein PevD1 was matched to the genomic sequence (GenBank accession no. ABJE 01000445.1) of a putative protein from V. dahliae strain vdls.17, but a function had not yet been reported. The pevD1 gene was expressed in Escherichia coli, and the recombinant protein was characterized for its ability to confer systemic acquired resistance to tobacco mosaic virus (TMV). Recombinant PevD1-treated plants exhibited enhanced systemic resistance compared to control, including a significant reduction in the number and size of TMV lesions on tobacco leaves. The elicitor protein-induced hydrogen peroxide production, extracellular-medium alkalization, callose deposition, phenolics metabolism, and lignin synthesis in tobacco. Our results demonstrate that elicitor-PevD1 triggers defense responses in intact tobacco plants.  相似文献   

12.
A composite linkage map was constructed based on two interspecific recombinant inbred line populations derived from crosses between Cicer arietinum (ILC72 and ICCL81001) and Cicer reticulatum (Cr5-10 or Cr5-9). These mapping populations segregate for resistance to ascochyta blight (caused by Ascochyta rabiei), fusarium wilt (caused by Fusarium oxysporum f. sp. ciceris) and rust (caused by Uromyces ciceris-arietini). The presence of single nucleotide polymorphisms in ten resistance gene analogs (RGAs) previously isolated and characterized was exploited. Six out of the ten RGAs were novel sequences. In addition, classes RGA05, RGA06, RGA07, RGA08, RGA09 and RGA10 were considerate putatively functional since they matched with several legume expressed sequences tags (ESTs) obtained under infection conditions. Seven RGA PCR-based markers (5 CAPS and 2 dCAPS) were developed and successfully genotyped in the two progenies. Six of them have been mapped in different linkage groups where major quantitative trait loci conferring resistance to ascochyta blight and fusarium wilt have been reported. Genomic locations of RGAs were compared with those of known Cicer R-genes and previously mapped RGAs. Association was detected between RGA05 and genes controlling resistance to fusarium wilt caused by races 0 and 5.  相似文献   

13.
 Twenty eight somatic hybrid plants were identified following protoplast fusions between peppermint (Mentha piperita L. cv Black Mitcham), producing high-quality oil, and spearmint (Mentha spicata L. cv Native Spearmint), likewise producing high-quality oil and also possessing resistance to verticillium wilt. Prior to fusion, peppermint protoplasts were subjected to iodoacetic acid to inhibit cell division. Protoplasts of peppermint and spearmint were fused using polyethylene glycol plus DMSO. Fusion products were cultured according to an efficient protoplast-to-plant-cycle protocol developed for peppermint. Using this protocol, iodoacetic acid-treated peppermint protoplasts were not able to divide, whereas untreated spearmint protoplasts had the ability to produce callus but not shoots. Therefore, selection of somatic hybrid calli was based on the presumed capability of hybrid cells to form calli and shoots. Shoots in vitro were initially identified as hybrids using RAPD profiles. Subsequently, observations on morphology, chromosome counts, and Southern-hybridization patterns confirmed their hybrid status. The results of verticillium tests revealed that 18 somatic hybrids were more susceptible than Native Spearmint, while hybrid II-14 had a level of susceptibility intermediate between that of the fusion parents. Oil-analysis of hybrid plants indicated that they all have a GC-profile typical of spearmint oil. Received: 8 February 1997 / Accepted: 9 April 1997  相似文献   

14.
A mutant strain of Penicillium citrinum grown in a chemically-defined production medium, yielded 145 mg compactin l–1. The medium also facilitated spectrophotometric analysis of compactin. Addition of KH2PO4in the production medium did not increase the compactin production, while addition of a surfactant, Tween 80, increased compactin to 175 mg l–1. Inoculation with 107 spores ml–1 and initial pH of 6.5–7 were the most suitable for compactin production.  相似文献   

15.
 The inheritance of an inter-simple-sequence-repeat (ISSR) polymorphism was studied in a cross of cultivated chickpea (Cicer arietinum L.) and a closely related wild species (C. reticulatum Lad.) using primers that anneal to a simple repeat of various lengths, sequences and non-repetitive motifs. Dinucleotides were the majority of those tested, and provided all of the useful banding patterns. The ISSR loci showed virtually complete agreement with expected Mendelian ratios. Twenty two primers were used for analysis and yielded a total of 31 segregating loci. Primers based on (GA)n repeats were the most abundant while primers with a (TG)n repeat gave the largest number of polymorphic loci. Nucleotides at the 5′ and 3′ end of the primers played an important role in detecting polymorphism. All the markers showed dominance. We found an ISSR marker linked to the gene for resistance to fusarium wilt race 4. The marker concerned, UBC-855500, was found to be linked in repulsion with the fusarium wilt resistance gene at a distance of 5.2 cM. It co-segregated with CS-27700, a RAPD marker previously shown to be linked to the gene for resistance to fusarium wilt race 1, and was mapped to linkage group 6 of the Cicer genome. This indicated that genes for resistance to fusarium wilt races 1 and 4 are closely linked. The marker UBC-855500 is located 0.6 cM from CS-27700 and is present on the same side of the wilt resistance gene. To our knowledge this is the first report of the utility of an ISSR marker in gene tagging. These markers may provide valuable information for the development of sequence-tagged microsatellite sites (STMS) at a desired locus. Received: 10 August 1997 / Accepted: 6 October 1997  相似文献   

16.
Summary Thirty-five representative gram-positive and 180 gram-negative strains of bacteria were isolated from the rhizosphere of Acala cotton plants which had escaped verticillium wilt. The gram-negative strains were divided into 9 groups on the basis of the oxidase test, anaerobic fermentation of glucose, 3-ketoglycoside formation, catalase, and fluorescent pigment formation. Most of these organisms wereE. carotovora types.In vitro antagonism toward Verticillium was exhibited by many of the soft-rotting organisms and several of the others. Dipping cotton seeds in a suspension of one antagonistic Agrobacterium strain or amending soil with a bacteria-carrot mixture prior to planting reduced the incidence and severity of verticillium wilt.  相似文献   

17.
Bioconversion of compactin into pravastatin by Streptomyces sp.   总被引:3,自引:0,他引:3  
Streptomyces sp. Y-110, isolated from soil, modified compactin to pravastatin, a therapeutic agent for hypercholesterolemia. In a batch culture, the highest production of pravastatin was 340 mg l–1 from 750 mg compactin l–1 in 24 h. By intermittent feeding of compactin into the culture medium, both the compactin concentration and its conversion increased to 2000 mg l–1 and 1000 mg pravastatin l–1, respectively, with the conversion rate of 10 mg l–1 h–1. Continuous feeding of compactin increased production of pravastatin to 15 mg l–1 h–1.  相似文献   

18.
An integrated molecular marker map of the chickpea genome was established using 130 recombinant inbred lines from a wide cross between a cultivar resistant to fusarium wilt caused by Fusarium oxysporum Schlecht. emend. Snyd. &. Hans f. sp. ciceri (Padwick) Snyd & Hans, and an accession of Cicer reticulatum (PI 489777), the wild progenitor of chickpea. A total of 354 markers were mapped on the RILs including 118 STMSs, 96 DAFs, 70 AFLPs, 37 ISSRs, 17 RAPDs, eight isozymes, three cDNAs, two SCARs and three loci that confer resistance against different races of fusarium wilt. At a LOD-score of 4.0, 303 markers cover 2077.9 cM in eight large and eight small linkage groups at an average distance of 6.8 cM between markers. Fifty one markers (14.4%) were unlinked. A clustering of markers in central regions of linkage groups was observed. Markers of the same class, except for ISSR and RAPD markers, tended to generate subclusters. Also, genes for resistance to races 4 and 5 of fusarium wilt map to the same linkage group that includes an STMS and a SCAR marker previously shown to be linked to fusarium wilt race 1, indicating a clustering of several fusarium-wilt resistance genes around this locus. Significant deviation from the expected 1 : 1 segregation ratio was observed for 136 markers (38.4%, P<0.05). Segregation was biased towards the wild progenitor in 68% of the cases. Segregation distortion was similar for all marker types except for ISSRs that showed only 28.5% aberrant segregation. The map is the most extended genetic map of chickpea currently available. It may serve as a basis for marker-assisted selection and map-based cloning of fusarium wilt resistance genes and other agronomically important genes in future. Received: 17 November 1999 / Accepted: 4 June 2000  相似文献   

19.
Pigeonpea is an important grain legume grown by smallholder farmers in Southern Africa. Fusarium wilt, caused by the fungal pathogen Fusarium udum Butler, is the major disease limiting pigeonpea production in the region. This study was designed to evaluate the reaction to fusarium wilt as well as agronomic performance of new elite pigeonpea germplasm in three different countries during the 2001/2002 cropping season using wilt‐sick plots. Per cent incidence of fusarium wilt (%FW), grain size and yield, were measured. The genotype ICEAP 00040 consistently showed a high (<20.0%) level of resistance to the disease in all three countries. In contrast, %FW score for the susceptible genotype ICEAP 00068 was 87.5, 92.0 and 90.9% in Kenya, Malawi and Tanzania, respectively. The grain size obtained for ICEAP 00040 at Ngabu (Malawi) was 25.0% larger than that at each of the remaining locations indicating environmental influence on this trait. At all the three locations, ≥1.5 ton/Ha of grain yield was obtained for ICEAP 00040 compared with <1.0 ton/Ha for ICEAP 00068. In 2003, this improved resistant genotype (ICEAP 00040) was released for commercial production and will be useful as a good source of resistance in pigeonpea genetic improvement programs in the region.  相似文献   

20.
Tomato is a popular vegetable widely grown in the tropics, which is mainly attacked by fusarium wilt incited by Fusarium oxysporum f. sp. lycopersici (FOL). In the present scenario, an ecofriendly alternative strategy such as use of fungi from rhizosphere is being explored to combat the phytopathogen invasion. This study was carried out to evaluate the efficacy of Trichoderma asperellum MSST to promote the growth and yield parameters of tomato S-22, a susceptible variety. This study was also undertaken to manage fusarium wilt disease under in vitro and in vivo conditions. Significant increase in vegetative parameters like root length, shoot length, plant weight and chlorophyll content 60 days after sowing (DAS) was observed. There was reduction in the incidence of fusarium wilt in tomato up to 85%. Increase in the level of total phenol, peroxidase, polyphenoloxidase and phenylalanine ammonium lyase activity at 10th day of pathogen inoculation showed enhancement of plant defence mechanism by T. asperellum MSST against FOL. Overall study revealed that isolate MSST was proven to be potential biocontrol agent showing induced resistance against FOL.  相似文献   

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