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1.
F. Favaron C. Castiglioni R. D'Ovidio P. Alghisi 《Physiological and Molecular Plant Pathology》1997,50(6):403-417
Five endo-polygalacturonases (PGs), three produced in culture filtrate byFusarium moniliforme, Sclerotium cepivorumandBotrytis aclada,respectively, and two (one acidic and one basic isoform) obtained fromSclerotinia sclerotiorumsoybean infected hypocotyls, were purified in order to characterize the activity of polygalacturonase inhibitor(s) (PGIP(s)) from leek stalk tissue (Allium porrumL.). Three apparently different PGIPs (PGIP-I, PGIP-II and PGIP-III) were purified from the leek tissue. The two more abundant PGIPs (PGIP-I and PGIP-III), although possessing similar pIs of about 6.5, differed in chromatographic behaviour, their molecular mass (39 and 42 kDa, respectively), and specific activity when assayed with the fungal endo-PGs. In addition, PGIP-I was solubilized from tissue homogenate with a low-salt buffer whilst PGIP-III needed a high-salt buffer for extraction (behaving as an ionically wall-bound protein). PGIP-II had very similar properties to PGIP-I, but was extracted using the high-salt buffer. The purified PGIPs and the crude leek extract showed similar inhibition activity patterns against the five fungal endo-PGs. The maximum inhibition activity was observed against the basic endo-PG fromS. sclerotiorum,followed by the acidic endo-PG ofS. sclerotiorumand the endo-PG fromB. aclada.In contrast, no inhibition of endo-PGs fromS. cepivorumandF. moniliformewas observed. Four different concentrations of the five fungal endo-PGs were incubated separately with slices of leek stalk, and the galacturonides released in the incubation mixture were measured. At every level used the endo-PGs ofF. moniliformeandS. cepivorumshowed the maximum activity in uronide releasing. The endo-PGs ofS. sclerotiorum(acidic PG) andB. acladawere active only when high levels were used while the basic endo-PG ofS. sclerotiorumwas not active in combustion with any level of PGIP. These results indicate that a close relationship exists between PGIP activityin vitroand the ability of PGIP to protect leek tissue from endo-PG degradation. 相似文献
2.
为明确新型生防菌解淀粉芽胞杆菌Bacillus amyloliquefaciens HRH317菌株对病原菌串珠镰孢菌Fusarium moniliforme的抑制作用,采用牛津杯法对HRH317菌株抑菌活性进行测定,并采用扫描电子显微镜、透射电子显微镜和荧光显微镜对经HRH317菌株发酵上清液处理后的串珠镰孢菌菌丝形态及超微结构进行观察。结果显示,HRH317菌株发酵上清液对串珠镰孢菌有很好的抑菌活性,抑菌圈平均直径可达33.31 mm。扫描电镜结果显示,HRH317菌株发酵上清液处理24 h时,串珠镰孢菌菌丝体出现断裂现象;处理72 h时,串珠镰孢菌菌丝体断裂较严重,多处裂解;处理96 h时,串珠镰孢菌菌丝体彻底瓦解,且无完整菌丝体。透射电镜结果显示,HRH317菌株发酵上清液处理72 h时,串珠镰孢菌菌丝体细胞形态扭曲变形,细胞内结构紊乱,遭破坏。荧光显微镜结果显示,经PI染料染色处理12 h时,串珠镰孢菌细胞有少数细胞被染成红色,细胞膜通透性受一定程度破坏;处理16 h时,串珠镰孢菌细胞大面积被染红;处理20 h时,串珠镰孢菌细胞被染色面积增大;处理24 h时,串珠镰孢菌细胞膜受破坏程度增加,细胞内大面积被染色。表明解淀粉芽胞杆菌HRH317菌株对串珠镰孢菌菌丝形态和超微结构有破坏作用,能抑制病原菌串珠镰孢菌菌丝体生长。 相似文献
3.
L. Daroda K. Hahn D. Pashkoulov E. Benvenuto 《Physiological and Molecular Plant Pathology》2001,59(6):317
The activation of Fusarium moniliforme endopolygalacturonase (endoPG) was studied during infection of maize plants. EndoPG is a plant cell wall degrading enzyme that cleaves the pectin component causing cell death. The authors generated several hybridoma cell lines producing endoPG specific monoclonal antibodies. One monoclonal antibody was selected and successfully used in Western blotting analysis to detect F. moniliforme endoPG secretion in vitro and in planta. Two F. moniliforme strains (FC-l0 and 62264) were used for the studies. Both strains revealed the expression of a single endoPG in vitro as in planta. EndoPG from strain FC-10 presented four isoforms whereas only two isoforms were revealed in the endoPG from strain 62264. Differences were also found in the sequences of the two endoPG genes indicating the presence of endoPG variability among F. moniliforme strains. 相似文献
4.
为探究自噬在核盘菌Sclerotinia sclerotiorum致病过程中的作用,利用酵母Saccharomyces自噬相关基因（autophagy-related gene,ATG）编码的蛋白序列比对核盘菌基因组,获得核盘菌假定ATG,并以核盘菌1980菌株为出发菌株,基于同源重组的原理对假定ATG进行敲除和回补,并测定不同突变体的生长表型和致病能力。结果表明,从核盘菌基因组中比对到2个ATG,分别命名为SsATG5和SsATG8,两者在核盘菌致病过程中均上调表达。SsATG5和SsATG8敲除突变体在菌丝生长、产草酸和侵染垫形成方面与野生型菌株无明显差异,但SsATG5敲除突变体在离体拟南芥Arabidopsis thaliana叶片上的致病力显著下降了约40%,在活体拟南芥植株上的致病力显著下降了约80%,同时SsATG5回补突变体恢复了正常的致病力。表明SsATG5参与了核盘菌的致病过程,证实自噬在核盘菌致病过程中发挥着重要作用。 相似文献
5.
Polygalacturonase-inhibiting protein (PGIP) from Japanese pear: possible involvement in resistance against scab 总被引：4，自引：0，他引：4
Mohamed Faize Tomoko Sugiyama Lydia Faize Hideo Ishii 《Physiological and Molecular Plant Pathology》2003,63(6):319-327
Venturia nashicola is the causal agent of scab, a fungal disease affecting Asian pears. The Japanese pear cv. ‘Kousui’ is highly susceptible to the race 1 of this fungus whereas the cv. ‘Kinchaku’ and the non-host European pear cv. ‘Flemish Beauty’ are resistant. The aim of this work is to investigate the role of polygalacturonase-inhibiting proteins (PGIPs) of pear during the interactions with V. nashicola leading to susceptibility or resistance. PGIP protein was detected from immature fruit of Kousui and Kinchaku. It showed a molecular mass of 42 kDa that shifted to 35 kDa after chemical deglycosylation. The gene pgip was amplified by PCR using genomic DNA and/or cDNA from young leaves of Kousui, Kinchaku, and European pear cvs. Flemish Beauty, ‘Bartlett’, and an Asian wild pear strain ‘Mamenashi 12’, then sequenced after sub-cloning. Some conserved variations were identified in the sequence indicating that gene family also exists in pgip of Japanese pear and confirmed by Southern blot analysis. The expression of PGIP was studied in scab-inoculated leaves of the susceptible Kousui and the resistant Kinchaku and Flemish Beauty. pgip Gene and its encoding protein were highly and rapidly activated in these resistant plants. In addition, PGIP extracts derived from Kinchaku and Flemish Beauty partially inhibited the activity of polygalacturonase (PG) from V. nashicola suggesting a possible role of PGIP in limiting fungal growth frequently observed in these resistant cultivars. 相似文献
6.
Abbas El-Hasan Frank Walker Jochen Schöne Heinrich Buchenauer 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(3):457-470
Antibiosis is assumed to be an essential mechanism exerted by potential biocontrol agents (BCAs) of Trichoderma spp. Therefore, in the present study, we report for the first time on the elucidation and production of viridiofungin A (VFA)
from T. harzianum isolate T23 cultures and investigate the antifungal potential of VFA and some other secondary metabolites purified from T. harzianum cultures against Fusarium moniliforme. The bioautography assay revealed that T. harzianum isolates T16 and T23 excreted several secondary metabolites with antifungal activity. Following isolation and purification
of the antifungal zones, three fractions (F223, F323 and F423) from extracts of isolate T23 and two fractions (F416 and F516)
from extracts of isolate T16 exhibited pronounced fungitoxic activity in the bioautography and antibiotic disk assays against
Cladosporium spp. and F. moniliforme, respectively. The structure of the antifungal metabolite in fraction F323 was identified as viridiofungin A (VFA), the first
report of production of VFA by isolate T23 of T. harzianum. Following cultivation of isolate T23 in PDB medium for 9 days, 94.6 mg l−1 of VFA were determined. VFA and fraction F516 retarded the mycelial growth of F. moniliforme in the non-volatile phase assay by >90% for each 250 μg ml−1 7 days post-inoculation (dpi). While VFA and fraction F416 showed both volatile and non-volatile effects, fraction F516 seemed
to exhibit mainly non-volatile activity. Microscopic examination revealed that hyphae of F. moniliforme grown on VFA-amended medium were less branched and appeared thicker than untreated hyphae. Furthermore, in the presence of
VFA, formation of chlamydospores by F. moniliforme was increased. Finally, the antifungal spectrum of VFA towards various important plant pathogens was evaluated. Germination
of propagules of a variety of fungal pathogens in vitro was differentially inhibited by VFA. While in the presence of 100 μg ml−1 VFA conidial germination of V. dahliae was completely inhibited, a slightly higher concentration (150 μg ml−1) of the inhibitor was required to suppress germination of Phytophthora infestans sporangia or sclerotia of Sclerotinia sclerotiorum. Contrary to several reports in the literature, VFA proved to be fungistatic rather than fungicidal. However, neither VFA
nor the other Trichoderma metabolites, such as 6PAP, F416 and F516, exhibited any antibacterial activity against Gram-positive and Gram-negative bacteria. 相似文献
7.
《Physiological and Molecular Plant Pathology》2000,56(3):117-130
Plant polygalacturonase inhibitor proteins (PGIPs) bind fungal polygalacturonases (PGs), but inhibition specificities and kinetics vary within and among species. Purified bean PGIP inhibited all fungal PGs we tested, includingFusarium moniliforme PG. Pear PGIP, however, was only effective against Botrytis cinerea PG. Moreover, tomato PGIP inhibited B. cinerea PG more than Aspergillus niger PG. Models of codon evolution for 22 dicot PGIPs and 19 fungal PGs indicated that advantageous substitutions dominate the molecular evolution of these genes and identified 9 amino acid residues, each, that are likely to evolve adaptively in response to natural selection. Many of these residues are within the β-strand/β-turn region of the PGIP LRR, including two sites known to alter inhibition specificities of bean PGIPs, but others lie outside this region. Our results complement existing molecular and biochemical studies of resistance specificity, and suggest new target amino acids for manipulating PG-inhibition. 相似文献
8.
Netted cantaloupe (Cucumis melo var. cantalupensis cv. Magnum 45) were harvested from 5 to 35 days postanthesis. The fruit of each age group were divided into exocarp, outer mesocarp, mid mesocarp, inner mesocarp, placenta, and seed. Each tissue was extracted and assayed for polygalacturonase-inhibiting protein (PGIP) activity against polygalacturonases (PGs) from three fungal pathogens of cantaloupe fruit. The PGIP activity of all tissues except placenta was high from the flower stage through the first week of fruit development but decreased markedly between 5 and 10 days postanthesis. PGIP activity against Phomopsis cucurbitae PG remained high and nearly constant in placental tissue throughout fruit development. However in this same tissue, PGIP activity against Fusarium solani PG decreased during fruit development to about 25% of its level in the 5-day-old fruit. This differential change in PGIP activity toward the two PGs suggests that different forms of the inhibitor are expressed between early and late stages of cantaloupe fruit development. The results also illustrate the importance of using multiple pathogen enzyme systems that can provide an opportunity for more accurate elucidation of mechanisms involved in the host–pathogen interaction. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. All programs and services of the US Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, age, marital status, or handicap. The article cited was prepared by a USDA employee as part of his/her official duties. Copyright protection under US copyright law is not available for such works. Accordingly, there is no copyright to transfer. The fact that the private publication in which the article appears is itself copyrighted does not affect the material of the US Government, which can be freely reproduced by the public. 相似文献
9.
为探讨解淀粉芽胞杆菌Bacillus amyloliquefaciens菌株HRH317对感染串珠镰孢菌Fusarium moniliforme玉米幼苗产生伏马毒素B_1(FB_1)的影响,采用牛津杯法测定菌株HRH317对串珠镰孢菌的抑制活性,并通过浸种处理进行盆栽试验,应用高效液相色谱技术对生长至3叶期后不同时间玉米幼苗叶片中FB_1含量进行测定,同时于室内测定玉米幼苗叶片防御酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)的活性。结果表明:解淀粉芽胞杆菌菌株HRH317能明显抑制串珠镰孢菌生长,抑菌圈直径平均可达33.31 mm;玉米幼苗生长至3叶期后1～6 d,菌株HRH317能有效抑制玉米植株体内FB_1含量,经串珠镰孢菌分生孢子悬浮液与菌株HRH317菌悬液1∶1混合液处理玉米种子后,对幼苗中FB_1的抑制率为59.20%～75.70%;而玉米种子先接种菌株HRH317菌悬液后接种串珠镰孢菌分生孢子悬浮液处理对幼苗中FB_1的抑制率为76.77%～88.10%。且这2种处理中幼苗叶片的SOD、CAT、PAL和POD活性均较对照有不同程度提高,其峰值是对照的1.24～5.45倍。表明解淀粉芽胞杆菌菌株HRH317可通过抑制FB_1产生来降低串珠镰孢菌对玉米幼苗的侵害,同时能诱导玉米植株体内防御酶活性的表达而增强其系统抗性,在防治玉米穗腐病方面具有潜在的应用价值。 相似文献
10.
Pauline A. Donaldson Terry Anderson Byron G. Lane Andrea L. Davidson Daina H. Simmonds 《Physiological and Molecular Plant Pathology》2001,59(6):297
Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) De Bary is a serious fungal disease of soybean. Senescing petals provide a starting nutrient source for the invasion of healthy tissue by the advancing oxalic acid secreting fungal hyphae. Since oxalic acid is a major pathogenicity factor of SSR, transgenic soybean capable of degrading oxalic acid may be resistant to the pathogen. Transgenic soybean plants were produced byAgrobacterium -mediated transformation with the wheat germin gene (gf-2.8) encoding an oligomeric protein, oxalate oxidase (OxO), which oxidizes oxalic acid to carbon dioxide and hydrogen peroxide (H2O2). Transgenic soybean homozygous for 35S- gf-2.8 produced an approx. 130 kDa protein indistinguishable from wheat germin, and with OxO activity. OxO activity was prominent in cell walls proximal to the site of pathogen attack. The transgenics had greatly reduced disease progression and lesion length following cotyledon and stem inoculation with S. sclerotiorum indicating that the germin gene product conferred resistance to SSR. This is the first report of plant resistance to the fungal pathogen S. sclerotiorum in transgenic plants expressing OxO. 相似文献
11.
Biological Control of Sclerotinia Diseases of Rapeseed by Aerial Applications of the Mycoparasite Coniothyrium minitans 总被引：1，自引：0，他引：1
G. Q. Li H. C. Huang H. J. Miao R. S. Erickson D. H. Jiang Y. N. Xiao 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(4):345-355
Indoor and field experiments were conducted to evaluate the efficacy of applying the mycoparasite Coniothyrium minitans to the aerial parts of rapeseed plants at the flowering stage to control sclerotinia diseases caused by Sclerotinia sclerotiorum. Under controlled conditions, a petal inoculation technique was used to determine the effect of conidial suspensions of C. minitans on suppression of sclerotinia leaf blight. Results showed that C. minitans was effective in inhibiting infection initiated by ascospores of S. sclerotiorum on flower petals by restricting mycelial growth of the pathogen. Suppression of lesion development was related to the conidial
concentration of C. minitans, with larger lesions at low concentration (5×103conidia ml−1), but smaller lesions at high concentration (5×104 conidia ml−1 or higher). When C. minitans-treated rapeseed leaves were inoculated with mycelia of S. sclerotiorum, C. minitans failed to prevent infection of leaves, but caused a significant reduction in number of sclerotia produced on the diseased
leaves. No significant difference in efficacy was detected between the two isolates of C. minitans, LRC 2137 and Chy-1, on the two rapeseed cultivars, Westar (spring type) and Zhongyou 821 (winter type). Results of field
trials showed a significant reduction of stem rot of rapeseed in four (1997, 1999, 2003 and 2004) out of five years by aerial
application of C. minitans, compared with controls. No significant difference in suppressive efficacy was observed between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + benomyl (50 μg ml−1) and benomyl (100 μg ml−1) in 2003, and between the treatments of C. minitans (106 conidia ml−1), C. minitans (106 conidia ml−1) + vinclozolin (100 μg ml−1) and vinclozolin (500 μg ml−1) in 2004. Sclerotia of S. sclerotiorum collected from diseased plants in plots treated with C. minitans in 1999, 2000 and 2003, or with C. minitans + benomyl in 2003 were infected by C. minitans at frequencies ranging from 21.3 to 54.5%. This study concludes that aerial spraying of C. minitans is an effective method for controlling sclerotinia diseases of rapeseed. 相似文献
12.
13.
为保障油料作物安全和绿色农业发展,从西藏自治区4个市收集5种甘蓝型油菜种子样品,通过平板分离获得种子可培养内生菌,对获得的菌株进行溶磷、解钾、固氮和产吲哚乙酸(indoleacetic acid,IAA)促生特性测定,筛选具有多种促生特性的菌株,测定其对禾谷镰孢菌Fusarium graminearum、油菜菌核病菌Sclerotinia sclerotiorum和燕麦镰刀菌F. avenaceum三种病原菌的拮抗性能及对油菜幼苗的促生效果,并对其进行分子生物学鉴定。结果显示,西藏油菜种子可培养内生菌丰富,优势菌为芽胞杆菌,共分离到110株内生菌,其中具有多种促生特性的菌株为12株,有4株菌株对禾谷镰孢菌、油菜菌核病菌和燕麦镰刀菌中2种以上菌有抑制作用,抑制率在49.50%～66.83%之间,分别为DJ-T-6、NM-8-10、DJ-L-4和BL-T-15菌株,经16S rDNA基因序列鉴定其分别为贝莱斯芽胞杆菌Bacillus velezensis、萎缩芽胞杆菌Ba. atrophaeus和缺陷短波单胞菌Brevundimonas diminuta,且均对油菜幼苗有显著的促生作用。表... 相似文献
14.
The polygalacturonases (PG) and oxalic acid produced by Sclerotinia sclerotiorum in infected soybean hypocotyls were investigated as elicitors of the phytoalexin glyceollin I.Purification to homogeneity through isoelectrofocusing and ion-exchange fast protein liquid chromatography revealed three endo-PG isoenzymes (PG-I, PG-II and PG-IV) and one exo-PG (PG-III) in 6-day-old etiolated soybean hypocotyls infected with the B-24 isolate of S. sclerotiorum.PG-I and PG-III, in the range of concentrations tested (0·15–1·2 reducing units ml−1), did not act as elicitors of glyceollin I synthesis. Some elicitor activity was shown by PG-II at 0·6–1·2 reducing units ml−1. PG-IV, at lower doses (0·038–0·30 reducing units ml−1), was even more effective in inducing phytoalexin synthesis. However higher concentrations of PG-IV induced tissue softening and decreased phytoalexin accumulation.PG-II and PG-IV released heat-stable elicitors from purified soybean cell walls supporting the evidence that uronides are intermediate inducers in elicitation by endo-PGs. Oxalic acid was an active elicitor of glyceollin I over the range of concentrations tested (0·31–20 m
) with the maximum at a concentration of 5 m
. The inability of oxalic acid to release uronides from purified cell walls makes it unlikely that uronide intermediate elicitors are involved in elicitation by oxalic acid. 相似文献
15.
Fusarium moniliforme is a widespread facultative endophyte, primarily associated with corn, where it causes extensive crop damage.F. moniliforme can be toxigenic, the carcinogenic fumonisins being accumulated predominantly when the fungus colonizes corn plants. The
pathogen is transmitted both through contaminated seeds and through environmental inoculum. This study utilized markednit-mutantF. moniliforme inoculum in order to evaluate the quantitative significance of seedborne disease transmission. Greenhouse and field trials
demonstrated that seedborne isolates were responsible for up to 50% ofF. moniliforme disease. Seed treatment with the fungicide prochloraz was found to control seedborne transmission and to protect againstF. moniliforme seedling blight. The elimination of seedborne inoculum resulted in reduced incidence of kernel rot and avoided the increment
in soil inoculum accumulation associated with the introduction of infected seeds.
http://www.phytoparasitica.org posting July 10, 2003. 相似文献
16.
Caroline Hennin Elke Diederichsen Monica Hfte 《Physiological and Molecular Plant Pathology》2001,59(6):287
Tomato and transgenic oilseed rape plants expressing the Cf-9 resistance gene develop a hypersensitive response (HR) after injection of the corresponding Avr9 gene product. It was investigated whether induction of a HR conferred resistance to different fungal pathogens in tomato and oilseed rape. Induction of an AVR9 mediated HR at the pathogen infection site delayed the development of the biotrophs Oidium lycopersicum in tomato and Erysiphe polygoni in oilseed rape, but enhanced the development of the necrotrophs Botrytis cinerea and Alternaria solani in tomato and Sclerotinia sclerotiorum in oilseed rape. Interestingly, delayed fungal disease development was observed in plant tissues surrounding the HR lesion regardless of whether a necrotrophic or biotrophic pathogen was used. In tomato, AVR9 injection induced systemic expression of PR1, PR2 and PR3 defence genes but did not induce systemic resistance to O. lycopersicum, B. cinerea or A. solani. In oilseed rape, AVR9 injection temporarily induced systemic resistance to Leptosphaeria maculans and E. polygoni, but did not induce detectable systemic expression of PR1, PR2 or Cxc750. These results give new insights into the potential uses of an induced HR to engineer disease resistance. 相似文献
17.
Jacqueline Freeman Elaine Ward Carmen Calderon Alastair McCartney 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(9):877-886
The development of a polymerase chain reaction (PCR) assay for the detection of inoculum of the plant pathogenic fungus Sclerotinia sclerotiorum is described. The PCR primers were designed using nuclear ribosomal DNA internal transcribed spacer sequences. Specific detection of DNA from S. sclerotiorum was possible even in the presence of a 40-fold excess of DNA from the closely related fungus Botrytis cinerea. PCR products were obtained from suspensions of untreated S. sclerotiorum ascospores alone, but DNA purification was required for detection in the presence of large numbers of B. cinerea conidiospores. Specific detection of inoculum of S. sclerotiorum was possible in field-based air-samples, using a Burkard spore trap, and from inoculated oilseed rape petals. The assay has potential for incorporation into a risk management system for S. sclerotiorum in oilseed rape crops. 相似文献
18.
Lian Wu Xie Shu Mei Jiang Hong Hui Zhu Wei Sun Yong Chang Ouyang Shi Kun Dai Xiang Li 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(4):571-578
Sclerotinia sclerotiorum is a worldwide ascomycete fungal plant pathogen, which causes enormous yield losses on major economic crops such as crucifers,
grain legumes and several other plant families. The objective of this research was to isolate and characterise some bioactive
products from cultures of fungi associated with the marine sponge Axinella sp. In total, nine fungal isolates were obtained from the marine sponge Axinella sp. collected from the South China Sea. A group of test strains, including two G+ strains (Bacillus subtilis and Staphylococcus aureus), two G− strains (Escherichia coli and Pseudomonas aeruginosa) and three fungi including two plant pathogenic fungi Sclerotinia sclerotiorum and Magnaporthe grisea and Saccharomyces cerevisiae, were employed as the indicator organisms for bioactivity screening. Using antagonistic tests and bioactive screening of
the ethyl acetate (EtOAc) extracts of the corresponding cultures, fungal isolate JS9 showed the stronger efficacy against
the test indicator strains, especially the indicator fungal pathogens. Isolate JS9 was further identified as Myrothecium sp. by a combination of morphological features and 18S rDNA BLAST on GenBank. Two macrocyclic trichothecenes, roridin A (compound
1) and roridin D (compound 2) were purified by tracking the activity of the EtOAc extract fractions and characterised with
spectral analyses including MS, 1H-NMR, 13C-NMR and disortionless enhancement by polarization transfer (DEPT). In vitro antifungal tests showed that the two macrocyclic trichothecenes were bioactive against S. cerevisiae, M. grisea and S. sclerotiorum with minimal inhibitory concentrations of 31.25, 125 and 31.25 μg ml−1 for roridin A, and 62.5, 250 and 31.25 μg ml−1 for roridin D, respectively. The present investigation demonstrated that two antifungal trichothecenes including roridin
A and roridin D produced by the fungus Myrothecium sp. isolated from the marine sponge Axinella sp. could be potential inhibitors against the plant pathogen S. sclerotiorum.
Lian Wu Xie and Shu Mei Jiang contributed equally to this work. 相似文献
19.
Blossom blight, caused bySclerotinia sclerotiorum, has become an important disease of alfalfa (Medicago sativa L.) in seed production areas of western Canada. Studies using light microscopy and scanning and transmission electron microscopy
revealed that pollen grains of alfalfa are susceptible to infection byS. sclerotiorum. Ascospores ofS. sclerotiorum germinated readily in water with or without pollen grains. Examinations of ascospore—pollen mixtures incubated at room temperature
(20–22°C) for 5 days revealed that numerous pollen grains were infected byS. sclerotiorum by direct hyphal penetration through the equatorial germinative pores or through the exine and intine layers of the pollen
wall without the formation of infection cushions or appressoria. After penetration, hyphae ramified within the pollen grains,
causing plasmolysis of the cytoplasmic membrane and eventual disintegration of the pollen cytoplasm. The study suggests that
alfalfa pollen may play a role in the epidemiology of blossom blight in alfalfa. 相似文献
20.
J. M. Whipps S. Sreenivasaprasad S. Muthumeenakshi C. W. Rogers M. P. Challen 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(3):323-330
The use of the sclerotial mycoparasite Coniothyrium minitans as a biological control agent of diseases caused by sclerotium-forming pathogens especially Sclerotinia sclerotiorum is briefly reviewed. A number of studies have examined production and application methods, integrated control, ecology, and
modes of action in order to understand the biology of the mycoparasite and enhance activity and reproducibility of use. Recently,
development of a number of molecular-based techniques has begun to allow the examination of genes involved in mycoparasitism.
Some of these procedures have been applied to identify pathogenicity genes involved in the infection of sclerotia of S. sclerotiorum by C. minitans and this work is discussed. 相似文献