Induced defense dynamics in plant parts is requisite for resistance to <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> (Hubner) infestation in chickpea     

Anterpreet Kaur  Satvir Kaur Grewal  Ravinder Singh  Rachana D. Bhardwaj 《Phytoparasitica》2017,45(4):559-576

Helicoverpa armigera is the most serious insect pest in chickpea that causes significant yield losses due to its feeding on vegetative (leaves) and reproductive (developing pods and seeds) parts of plants. The present aim of study was to explore response dynamics of induced defence mechanism in leaves, podwall and seeds of ten chickpea genotypes (ICC 506, ICCV 10, ICC 10393, 5283, RSG 963, GL 25016, GL 26054, ICCL 86111, ICC 3137, L 550) after insect infestation. Two chickpea genotypes namely ICC 3137 and L 550 were found to be highly susceptible to Helicoverpa armigera infestation due to higher leaf and pod damage in them as compared to rest of eight genotypes which are found to be considerably resistant due to lower damage. Insect infestation induced decreased activities of defensive enzymes such as peroxidase (POD), catalase (CAT), glutatione reductase (GR) and polyphenol oxidase (PPO), decreased free radical scavenging activities in terms of 2,2-diphenyl-1-picryl hydrazyl (DPPH), decreased contents of signaling molecules such as nitric oxide ((NO), hydrogen peroxide (H₂O₂), reduced content of insect feeding behaviour regulating molecules such as total phenols, trypsin inhibitor and accumulation of membrane damage marker such as malondialdehyde (MDA) in leaves of ICC 3137 and L 550; decreased POD activity, nitric oxide content and H₂O₂ in podwall of L550; decreased SOD, GR, nitric oxide content and H₂O₂ in seeds of L550 resulted in aggravation of infestation induced oxidative stress and makes these genotypes more vulnerable to insect damage. The resistance of rest eight chickpea genotypes to insect infestation was due to the integrative effect of up regulated defensive components in leaves, podwall and seeds such as enhanced activities of CAT, POD, GR, PPO and PAL along with accumulation of H₂O₂` and total phenols in leaves, increased SOD, POD, GR and PPO activities along with increased contents of trypsin inhibitor and total phenols in podwall; increased SOD, GR, PPO activities and accumulated total phenols in seeds of resistant chickpea genotypes might be responsible for causing significant shift in oxidative status of these genotypes due to scavenging of free radicals, maintenance of membrane integrity and deterrent to insect feeding. Induced glycine betaine after herbivory was found to be positively correlated with superoxide dismutase and trypsin inhibitors. H₂O₂ content was positively correlated with trypsin inhibitor, DPPH, ferric reducing antioxidant power (FRAP) and total phenols in leaves and with FRAP, DPPH and total phenols in pod wall indicating that H₂O₂ might be stimulating the cascade that will be helping to scavenge free radical species and correlation with phenols and trypsin inhibitor indicated that it act as toxicant to insect feeding.  相似文献   

Application of energy-filtering electron microscopy (EFEM) for analysis of hydrogen peroxide and lignin in epidermal walls of cucumber leaves triggered by acibenzolar-S-methyl treatment prior to inoculation with Colletotrichum orbiculare     

P. Park  T. Kurihara  M. Nita  K. Ikeda  K. Inoue  H. Ishii 《Plant pathology》2019,68(9):1624-1634

Hydrogen peroxide (H₂O₂) and lignin induced by acibenzolar-S-methyl (ASM) during the expression of systemic acquired resistance (SAR) of cucumber plants against the fungus Colletotrichum orbiculare was analysed with electron microscopy and energy-filtering electron microscopy (EFEM). ASM pretreatment consistently led to the blockage of appressorial penetration pegs into leaves at early stages after inoculation, whereas the fungus was able to grow into the vascular tissue after distilled water pretreatment. The blocked pegs, seen frequently at epidermal pectin layers in leaves of ASM-treated plants, were surrounded by abundant electron-dense amorphous material and dots. These were identified as lignin, based on their appearance and high reactivity with KMnO₄. Lignin first appeared as an amorphous material at pectin layers, and then as dots in some areas of the material. The results showed that ASM caused SAR in leaves via faster formation of lignin within 1 day after inoculation. After CeCl₃ treatment to detect H₂O₂, H₂O₂-reactive products (cerium perhydroxides) were seen near ASM-induced lignin formation sites in pectin layers. EFEM analysis showed that Ce and O were located at the same sites as the lignin dots, suggesting that lignin was associated with sources of H₂O₂ generation. The results indicate that the faster H₂O₂ generation and lignification induced by ASM were the potential causes of SAR.  相似文献   

Microscopic detection of reactive oxygen species generation in the compatible and incompatible interactions of Alternaria alternata Japanese pear pathotype and host plants     

Takeshi Shinogi  Tomoko Suzuki  Takayuki Kurihara  Yoshihiro Narusaka  Pyoyun Park 《Journal of General Plant Pathology》2003,69(1):7-16

 Reactive oxygen species (ROS) generation was examined in the interaction of Alternaria alternata Japanese pear pathotype and host plants using three methods: nitro blue tetrazolium (NBT) method for microscopic detection of O₂ ⁻, diaminobenzidine (DAB) methods for microscopic detection of H₂O₂, and cerium chloride methods for ultrastructural detection of H₂O₂. ROS generation was detected by NBT and DAB methods at appressoria on leaves of susceptible cultivars and heat-shocked leaves of resistant cultivars but not in leaves of resistant cultivars. Ultrastructural detection by the cerium chloride method identified ROS generation at cell walls of appressoria and penetration pegs in susceptible, resistant leaves and heat-shocked leaves. These differences in the ultrastructural and microscopic data in resistant areas were due to the restriction of ROS generation in limited areas, the side facing the plant surface, of appressoria and penetration pegs. Therefore, ROS generation was apparently induced regardless of the resistance or susceptibility of the cultivar with the difference being in the volumes generated. After evaluating the pathological role of ROS generation in fungal structures, such generation was found to be associated with early penetration of cell walls in pear plants. Additionally, ROS generation in plants was also found in degrading pectin layers near infected hyphae and in plasma membrane modification sites in susceptible leaves but not in resistant leaves. ROS generation in susceptible leaves might be accompanied with plasma membrane damage, although the role of ROS generation in the pectin layers is not clear. ROS generation in both fungal and plant cells during their interaction was likely associated with the expression of susceptibility. Received: June 3, 2002 / Accepted: July 31, 2002  相似文献   

The relation of mansonones to resistance against dutch elm disease and their accumulation,as induced by several agents     

D. M. Elgersma  J. C. Overeem 《European journal of plant pathology / European Foundation for Plant Pathology》1971,77(5):168-174

No evidence was found that mansonones E and F, which accumulated in elms after infection withCeratocystis ulmi, were responsible for resistance against Dutch elm disease inUlmus hollandica cl. 390. Furthermore, production of mansonones inU. americana was only about one-fifteenth of that inU. hollandica cl. Belgica. Yet both are susceptible to Dutch elm disease.Induction of these compounds was not specific, for accumulation occurred not only after introduction of crude toxin ofC. ulmi, but also after inoculation withVerticillium albo-atrum and after introduction of H₂SO₄ or ethanol.The dark discolouration of the wood after toxin treatment was restricted to the lower part of the stem. No mansonones could be detected in the non-discoloured higher parts of the stem or from the necrotic or wilted leaves.Samenvatting Er werd geen aanwijzing gevonden dat mansononen E en F, die na infectie metC. ulmi gevormd worden, verantwoordelijk zijn voor de resistentie tegen de iepziekte inU. hollandica cl. 390 (Tabel 1). U. americana bevat ongeveer 15 maal zo weinig van deze stoffen alsU. hollandica cl. Belgica, terwijl beide vatbaar zijn.De inductie van de synthese van deze stoffen bleek niet specifiek te zijn, omdat bij chemische beschadiging met H₂SO₄ of ethanol ook mansononen gevormd werden.De donkere verkleuring van het hout bleek na toxine toediening beperkt tot het onderste gedeelte van de stam. Geen mansononen werden gevonden in hoger gelegen, niet verkleurde stamgedeelten of in de necrotische en verwelkte bladeren.  相似文献   

The effect of leaf age on incomplete resistance of coffee to Hemileia vastatrix     

A. B. Eskes  M. Toma-Braghini 《European journal of plant pathology / European Foundation for Plant Pathology》1982,88(6):219-230

The influence of leaf age on incomplete resistance to race II of coffee leaf rust (Hemileia vastatrix), which is the most common race in Brazil, was tested in the greenhouse and in the field. Three stages of leaf age were distinguished: young leaves which had just fully expanded and still had a shiny appearance on the day of inoculation, adult leaves of 1 to 4 months old, and old leaves of 6 to 12 months old which were formed in the foregoing growing season.The effect of leaf age varied with the coffee genotype. With the susceptibleCoffea arabica cvs Mundo Novo and Catuai no important effect of leaf age on latency period and reaction type was observed. Lesion density, depending on inoculation method, was affected to some extent, older leaves showing lower values. With genotypes of theC. canephora cv. Kouillou, which varied in level of incomplete resistance, adult leaves appeared to be more resistant than young and old leaves. This adult leaf resistance was expressed mainly by a lower lesion density, but also by a longer latency period and a lower reaction type.Within the hybrid populations Icatu and Catimor, genotypes with race-specific incomplete resistance were tested and others of unknown specificity. Resistance was expressed mainly by a low reaction type. Generally, resistance decreased with increasing leaf age, which was occasionally associated with a complete change in reaction type. Contrary to cv. Kouillou, in Icatu and Catimor no higher susceptibility of young leaves than of adult leaves was observed.The incomplete resistance to race I of the differential CIFC H152/3, heterozygous for S_H4, was also better expressed in young leaves, older ones becoming gradually more susceptible.It is concluded that for screening incomplete resistance to coffee leaf rust leaves of different ages should be tested.Samenvatting Het effect van bladleeftijd op incomplete resistentie van koffie tegen fysio II van koffieroest (Hemileia vastatrix), het algemeen voorkomende fysio in Brazilië, werd getoetst in de kas en in het veld. Drie stadia in de bladleeftijd werden onderscheiden: jong blad dat net volgroeid was en nog glansde op de dag van inoculatie, volwassen blad van 1 tot 4 maanden oud en oud blad van 6 tot 12 maanden oud dat gevormd was in het voorafgaande groeiseizoen.Het effect van bladleeftijd varieërde met het koffiegenotype. Bij de vatbareCoffea arabica rassen Mundo Novo en Catuai werd geen belangrijke invloed waargenomen van bladleeftijd op latentieperiode en reactietype. Lesiedichtheid werd, afhankelijk van de inoculatiemethode, wel enigszins beïnvloed. Bij vijf genotypen van hetC. canephora ras Kouillou, die varieerden in niveau van incomplete resistentie, bleek volwassen blad veelal resistenter dan jong en oud blad. Deze resistentie uitte zich voornamelijk door een lagere lesiedichtheid maar ook door een langere latente periode en een lager reactietype.Van de hybride populaties Icatu en Catimor werden enkele genotypen met fysiospecifieke incomplete resistentie getoets alsmede genotypen waarvan de specificiteit van de resistentie onbekend was. Verschillen in resistentie uitten zich voornamelijk door verschillen in reactietype. Over het algemeen nam de resistentie af bij toenemende bladouderdom. Anders dan bij de cv. Kouillou werd bij Icatu en Catimor geen grotere vatbaarheid van jong ten opzichte van volwassen blad waargenomen. Bij sommige genotypen kwam resistantie zelfs alleen maar tot uiting in het jonge blad, terwijl het volwassen blad normaal vatbaar was. Een soortgelijk effect van bladleeftijd werd waargenomen bij inoculatie van de koffiedifferentieel CIFC H153/3, die heterozygoot is voor het resistentiegen S_H4, met het incompatibele fysio I.Er wordt geconcludeerd dat voor het bepalen van incomplete resistentie tegen koffieroest bladeren van verschillende ouderdom getoetst dienen te worden.  相似文献   

Changes in susceptibility of bean leaves (Phaseolus vulgaris) to Sclerotinia sclerotiorum and Botrytis cinerea by pre-inoculative ozone exposures     

A. E. G. Tonneijck  G. Leone 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(5-6):313-322

The effects of ozone on the susceptibility of leaves ofPhaseolus vulgaris toSclerotinia sclerotiorum andBotrytis cinerea have been investigated. Seedlings of one ozone-sensitive (Pros) and five relatively ozone-insensitive cultivars (Gamin, Precores, Groffy, Narda, Berna) were exposed to different ozone concentrations (0, 120, 180 and 270 g m^–3) for 8 h. One day after the exposures, primary leaves were detached and immediately inoculated with spores of either pathogen suspended in water or in a 62.5 mM KH₂PO₄ (Pi) solution. Visible ozone injury differed between the cultivars and increased with increasing ozone concentration. On the leaves of non-exposed plants, spores of the pathogens suspended in water caused very few lesions, whereas fungal pathogenicity was stimulated by addition of Pi to the inoculum. Ozone-injured leaves of all cultivars exhibited lesions after inoculation of the leaves with the pathogens suspended in water, and the number of lesions was positively correlated with the level of ozone injury for either pathogen and cultivar. The increase in susceptibility of bean leaves in response to increasing ozone concentrations was greater forB. cinerea than forS. sclerotiorum when spores were suspended in water, but was similar when the spores were suspended in Pi.In general, the number of lesions following inoculation with spores in Pi increased with increasing ozone concentration. However, the number of lesions in the ozone-insensitive Groffy was reduced by an exposure to 120 g m^–3 but increased with higher concentrations. This pattern of susceptibility response to the pathogens was not found in the other ozone-insensitive cultivars and, thus, did not appear to be related to the inherent ozone-insensitivity in bean.  相似文献   

Bentazone and bromoxynil induce H and H₂O₂ accumulation, and inhibit photosynthetic O₂ evolution in Synechococcouselongatus PCC7942     

Palash Kumar Das 《Pesticide biochemistry and physiology》2010,97(3):256-261

Using a unicellular cyanobacterium, Synechococcouselongatus PCC7942, we have shown that cytosolic acidification, O₂⁻; H₂O₂ production and photosystem II-inactivation are the causes of cell death from bentazone/bromoxynil incubations. Butyric acid evoked solely pH lowering response and yet inhibited PS II activity indicating that herbicide-caused acidification is sufficient to kill the cyanobacterial cells, but other factors like excess H₂O₂ production due to an imbalance in the peroxide sequestration machinery might be contributory. While the activities of superoxide dismutase and pyrogallol peroxidase increased consequent to herbicide incubations and displayed oligomeric states with mobility shift, catalase and glutathione peroxidase though present remained insensitive.  相似文献   

Effect of dimethoate and UV-B irradiation on the response of antioxidant defense systems in cowpea (Vigna unguiculata L.) seedlings     

Vagish Mishra  Pragya MishraGarima Srivastava  Sheo Mohan Prasad 《Pesticide biochemistry and physiology》2011,100(2):118-123

  相似文献   

Effects of leaf blast on photosynthesis of rice. 1. Leaf photosynthesis     

L. Bastiaans 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(4):197-203

The effect ofPyricularia oryzae, the causal organism of leaf blast in rice, on photosynthesis characteristics of rice leaves was measured in two greenhouse experiments. Leaf blast reduced photosynthesis not only through a reduction in green leaf area, but also through an effect on photosynthesis of green leaf tissue surrounding the lesions. The assimilation rate at light saturation (P _max ) was more affected than the initial light use efficiency (). Dark respiration (R _d ) increased as a result of infection. The experimental data were used to derive relations between leaf blast severity andP _max , andR _d .  相似文献   

A biochemical mechanism for the gene-for-gene resistance of tomato to Cladosporium fulvum     

A. Van Dijkman  A. Kaars Sijpesteijn 《European journal of plant pathology / European Foundation for Plant Pathology》1971,77(1):14-24

Model experiments were carried out with the tomato varieties Moneymaker (no resistance genes), Leaf Mould Resister No. 1 (resistance gene Cf 1), Vetomold (resistance gene Cf 2) and V 473 (resistance genes Cf 1 and Cf 2) and various physiological races ofCladosporium fulvum. Leaking of³²P from labelled leaf disks, was obtained on infiltration with high molecular weight excretion products from incompatible races ofC. fulvum but not with those from compatible races. These products were obtained by Sephadex G-25 gel filtration of culture filtrates.The observations are in line with our hypothesis that the gene-for-gene relation existing between tomato andC. fulvum is based on interaction of specific fungal excretion products with specific receptors in the host which may be located in the cell membrane. The presence of these fungal compounds is supposed to be controlled by four avirulence genes (A₁, A₂, A₃ and A₄) and that of the receptors by the four resistance genes (Cf 1, Cf 2, Cf 3 and Cf 4). Results obtained from experiments with tomatoes Cf 1, Cf 2 and Cf 1 Cf 2 suggest that leakage followed by the hypersensitivity reaction occurs whenC. fulvum races possessing a specific avirulence allele penetrate into a host carrying the corresponding resistance allele.It is not yet clear why growth ofC. fulvum is stopped when leakage of the host tissue resulting in the hypersensitive reaction takes place. No compound toxic toC. fulvum is present or is formed in homogenates of tomato leaves.Samenvatting Modelproeven werden uitgevoerd met de tomatenvariëteiten Moneymaker (geen resistentiegenen), Leaf Mould Resister No. 1 (resistentiegen Cf 1), Vetomold (resistentiegen Cf 2), V 473 (resistentiegen Cf 1 en Cf 2) en verschillende fysiologischen rassen vanCladosporium fulvum. Bladponsjes van radioactief gemerkte bladeren (gemerkt met³²P) werden geïnfiltreerd en geïncubeerd met cultuurfiltraatfracties (fractionering over Sephadex G-25) vanC.fluvum. Waargenomen werd dat ponsjes, behandeld met cultuurfiltraat van een niet compatibeleC.fulvum, een grotere uitlek van radioactief gemerkt materiaal te zien gaven dan in de, gevallen waarin een compatibele schimmel werd gebruikt.Deze waarnemingen stemden overeen met onze hypothese dat de gen-om-gen relatie die bestaat tussen tomaten enC.fulvum, gebaseerd, is op een interactie van specifieke schimmelprodukten met specifieke receptoren in de plantencellen, mogelijk in de membranen. De produktie van de specifieke stoffen door de schimmel zou worden bepaald door vier avirulentiegenen (A₁, A₂, A₃ en A₄), en de aanwezigheid van de specifieke receptoren in de plantencel door de vier resistentiegenen Cf 1, Cf 2, Cf 3 en Cf 4.De waarnemingen, verkregen uit de proeven met de tomaten Cf 1, Cf 2 en Cf 1 Cf 2, doen vermoeden dat de uitlek een gevolg is van een overgevoeligheidsreactie die optreedt, indien een fysio vanC.fulvum, dat een specifiek avirulentie allel bezit, een gastheer binnendringt die beschikt over een bijpassend resistentie allel.Het is tot nu toe niet duidelijk waarom de groei vanC.fulvum stopt indien, uitlek op gaat treden als gevolg van de overgevoeligheidsreactie. In homogenaten van tomatenbladeren werd geen stof gevonden die de groei vanC.fulvum remt.  相似文献   

Toxigenic Fusarium Species of Liseola Section in Pre-harvest Maize Ear Rot, and Associated Mycotoxins in Slovakia     

Antonia Srobarova  Antonio Moretti  Rosalia Ferracane  Alberto Ritieni  Antonio Logrieco 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(4):299-306

The occurrence of Fusarium species of Liseola section and related toxins was investigated for two years (1996 and 1998) on maize ear rot samples collected in the most important areas for maize growing in Slovakia. The species most frequently isolated was F. verticillioides, followed by F. proliferatum in 1996 and F. subglutinans in 1998. Most of the strains belonged to mating populations A, D, and E of the teleomorph Gibberella fujikuroi. Fusarium graminearum was also frequently recovered in both the years of investigations. Toxin analysis of maize ears showed that most of the samples (21 out of 22) were contaminated with at least one toxin. In particular, the concentration of fumonisin B₁, and fumonisin ₂ was up to 26.9 and 5.1gg^-1, respectively in 1996, and up to 12.1 and 6.3gg^-1, respectively in 1998. Beauvericin was detected only in one sample in 1996. Seven samples in 1996 were contaminated by fusaproliferin up to 8.2gg^-1, but just traces of the toxin were found in one sample in 1998. All 29 strains of F. verticillioides, two of three strains of F. proliferatum and none of eight F. subglutinans strains isolated from samples produced fumonisin B₁ in culture on whole maize kernels (0.1–5646 and 940–1200ugg^-1, respectively). Two strains of F. subglutinans and two of F. proliferatum produced beauvericin (up to 65 and 70gg^-1, respectively). Ten strains of F. verticillioides produced beauvericin: 9 strains produced a low amount (up to 3gg^-1), while only one of them produced a high level of toxin (375gg^-1). Fusaproliferin was produced by two F. proliferatum strains (220 and 370gg^-1), by seven F. subglutinans (20–1335gg^-1) and by three F. verticillioides (10–35gg^-1). This is the first report on fusaproliferin production by F. verticillioides, although at low level.  相似文献   

Acibenzolar-S-methyl Induces the Accumulation of Defense-related Enzymes in Apple and Protects from Fire Blight   总被引：4，自引：0，他引：4  

Marie-Noëlle Brisset  Sophie Cesbron  Sherman V. Thomson  Jean-Pierre Paulin 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(6):529-536

Acibenzolar-S-methyl (Novartis) is a chemical inducer of systemic acquired resistance in several annual plants. The ability of this novel chemical to induce resistance was studied in a perennial plant (apple) affected by fire blight caused by Erwinia amylovora. Acibenzolar-S-methyl (100 and 200mg/l active ingredient) protected Golden Delicious seedlings, scions and trees from artificial infection when applied before inoculation. The protection of apple seedlings was similar to the protection obtained with the standard for fire blight control, plantomycin (100mg/l streptomycin sulfate), applied immediately before inoculation. The mean levels of control in scions in the greenhouse and in trees in orchards were approximately 69% and 50%, respectively. The protection of apple seedlings was constantly associated with the activation of two families of defense-related enzymes, peroxidases and -1,3-glucanases. Accumulation of both enzymes was induced locally in treated leaves and systemically, especially for -1,3-glucanases, in upper untreated leaves, and was sustained for at least 17 days. These results suggest that acibenzolar-S-methyl promotes induced systemic resistance in apple by increasing defense-related compounds. This chemical could provide a new approach of control of fire blight but its practical use needs further investigation.  相似文献   

Characterization and mapping of a spotted-leaf genotype,spl Y181 that confers blast susceptibility in rice     

Huimin Sun  Jiejing Mao  Bo Lan  Chunjiao Zhang  Chenchen Zhao  Gang Pan  Xiaohua Pan 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(3):407-417

A spotted-leaf mutant Y181, produced by ⁶⁰Co_γ-radiation treatment of Zixuan1, was identified in rice. The result of TEM demonstrated the number of starch grains decreased significantly, the distribution and volumes of osmiophilic granules and lipid balls were larger in the leaf cells around the lesion mimics, the chloroplasts in mesophyll cells disappeared and just leaving a few rupture thylakoid membranes in the cytoplasm and some transmutative starch granules in Y181. Compared with the wild type, the content of chlorophyll was decreased significantly, while the H₂O₂ content, and SOD, POD and CAT activity were obviously increased in mutant. DAB staining and H₂O₂ treatment further revealed oxidative burst in spotted leaves. Expression of lesion-related gene showed RuBisCo-L, RuBisCo-S, PDI and TPX was down-regulated, while PBZ1 was up-regulated in the leaf cell at the lesion mimics. Disease reaction to Magnaporthe grisea indicated that the resistance of Y181 was reduced. Genetic analysis showed that the mutant was controlled by a recessive nuclear gene, which was delimited to a 390 kb region between CH12-936 and RM7195.  相似文献   

Inhibitory influence of inorganic salts on banana postharvest pathogens and preliminary application to control crown rot   总被引：4，自引：0，他引：4  

Dionisio G.?Alvindia  Takao?Kobayashi  Keiko T.?NatsuakiEmail author  Seinosuke?Tanda 《Journal of General Plant Pathology》2004,70(1):61-65

Lasiodiplodia theobromae, Thielaviopsis paradoxa, Colletotrichum musae, C. gloeosporioides, Fusarium verticillioides, and F. oxysporum were screened in vitro for sensitivity to Na₂CO₃, NaHCO₃, CaCl₂, NaCl, and NaClO. The spore germination of all pathogens was completely inhibited by Na₂CO₃ 4g/l, NaClO 5g/l, and NaHCO₃, CaCl₂, and NaCl 6g/l each. Dipping the bananas for 10–15min in these concentrations reduced the incidence of crown rot (compared with the untreated fruits) 17 days after harvest in fruits treated with NaClO by 67%, with NaHCO₃ by 62%, with NaCl by 38%, and with CaCl₂ by 33%. Na₂CO₃-treated fruits had the same incidence of crown rot as untreated fruits.  相似文献   

Quantitative detection of <Emphasis Type="Italic">Colletotrichum godetiae</Emphasis> and <Emphasis Type="Italic">C. acutatum sensu stricto</Emphasis> in the phyllosphere and carposphere of olive during four phenological phases     

Leonardo Schena  Ahmed Abdelfattah  Saveria Mosca  Maria G. Li Destri Nicosia  Giovanni E. Agosteo  Santa O. Cacciola 《European journal of plant pathology / European Foundation for Plant Pathology》2017,149(2):337-347

A duplex qPCR detection method was developed to detect and quantify Colletotrichum godetiae and C. acutatum sensu stricto (s.s.) in olive tissues. The method proved highly specific and sensitive with a detection limit of 10 pg for each pathogen. The analysis of green and senescent leaves, fertilized fruitlets with floral residues, green fruit and symptomatic and asymptomatic fruit collected in May, June, October and December revealed a high incidence of both C. godetiae and C. acutatum s.s. in Calabria, southern Italy. In comparison with previous reports, these results highlighted an ongoing population shift from C. godetiae to C. acutatum s.s. Interestingly, C. godetiae was slightly more abundant in terms of number of infected samples, yet the quantity of C. acutatum in infected samples was always higher, suggesting greater aggressiveness and/or sporulation ability of the latter pathogen. The populations of both C. godetiae and C. acutatum s.s. increased sharply in December even though both pathogens were detected widely in asymptomatic samples in May, June and October, confirming an important role of latent infections in the disease cycle. A large quantity of both C. godetiae (1.7 × 10⁸ cells/mg of tissue) and C. acutatum s.s. (7.5 × 10⁸ cells/mg of tissue) was estimated in symptomatic fruit, presenting an enormous inoculum potential for secondary infections. Two other important observations were a high incidence and quantity of both pathogens in senescent leaves and in fertilized fruitlets with floral residues as compared to green leaves.  相似文献   

Effects of Host and Microbial Factors on Development of Clonostachys rosea and Control of Botrytis cinerea in Rose     

Marcelo A.B. Morandi  John C. Sutton  Luiz A. Maffia 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(5):439-448

Development of Clonostachys rosea in rose leaves and petals and control of Botrytis cinerea by the agent were investigated. C. rosea germinated, established endophytic growth, and sporulated abundantly whether the tissues were mature, senescent or dead when inoculated. Germination incidence was moderate on mature and senescent leaves (47% and 35%) and petals (31% and 43%), and high (>98%) on dead tissues. Sporulation of C. rosea in tissues inoculated when mature, senescent or dead averaged 41%, 61%, and 75% in leaves, and 48%, 87% and 53% in petals. When leaves were wounded with needles before inoculation, germination of C. rosea increased from 45–56% to 90–92%, but sporulation became high (>75%) regardless of wounds. When leaves were inoculated with C. rosea at 0–24h after wounding and subsequently with B. cinerea, germination of the pathogen was reduced by 25–41% and sporulation by 99%. A humid period prior to inoculation of senescent or dead leaves promoted communities of indigenous fungi, reduced sporulation of C. rosea and B. cinerea, and, in dead leaves, increased control of the pathogen associated with C. rosea. Applied at high density, isolates of indigenous Penicillium sp. and Alternaria alternata from rose interacted with C. rosea and reduced control of the pathogen by 16% and 21%, respectively. In conclusion, C. rosea markedly suppressed sporulation of B. cinerea in rose leaves and petals regardless of developmental stage, minor wounds, and natural densities of microflora. This versatility should allow C. rosea to effectively control inoculum production of B. cinerea in rose production systems.  相似文献   

Spatial and temporal changes in chlorophyll fluorescence images of Nicotiana benthamiana leaves following inoculation with Pseudomonas syringae pv. tabaci     

M. J. Iqbal  P. H. Goodwin  E. D. Leonardos  B. Grodzinski 《Plant pathology》2012,61(6):1052-1062

Inoculation of Nicotiana benthamiana leaves with virulent and avirulent strains of Pseudomonas syringae pv. tabaci resulted in increasing changes in F_v/F_m, and NPQ over time. Images of these chlorophyll a fluorescence measurements revealed different changes in different zones of the leaf. For the virulent strain, the infiltrated zone and zone directly surrounding it showed decreased F_v/F_m, and NPQ before the appearance of visible symptoms, and these decreases corresponded with increasing bacterial populations and putative tabtoxin activity. Another distinct zone of reduced F_v/F_m and NPQ extended several centimetres from the lesion to the nearest leaf margin, but only very low bacterial populations and no putative tabtoxin activity were detected in this zone. For the avirulent strain, a hypersensitive response occurred, bacterial populations remained low, and there was little detectable putative tabtoxin activity. Decreased F_v/F_m and NPQ, but not , were observed in the infiltrated zone prior to the hypersensitive response, followed by decreased values in a zone directly surrounding it. Following that, no further changes were observed. These results demonstrate that in addition to detecting pre‐symptomatic impacts of bacteria, chlorophyll a fluorescence imaging can also show that there are highly distinct regions of affected tissue that can extend considerably beyond the area of bacterial colonization. This should be considered in selecting leaf tissues for examining the effects of pathogens on plants, such as altered host gene expression or protein levels.  相似文献   

The buffering capacity of the natural mycoflora of rye leaves to infection by Cochliobolus sativus,and its susceptibility to benomyl     

N. J. Fokkema  J. A. J. van de Laar  A. L. Nelis-Blomberg  B. Schippers 《European journal of plant pathology / European Foundation for Plant Pathology》1975,81(5):176-186

Different densities of saprophytic colonization of rye leaves were obtained in field experiments by spraying with benomyl or water. In 1972 and in 1973, inoculation withCochliobolus sativus, just after flowering, resulted in 60% less necrosis on water-sprayed leaves than on benomyl-sprayed leaves. At that time, the natural mycoflora of the water-sprayed leaves amounted to 10 000 and 3000 propagules per cm² leaf surface in 1972 and 1973, respectively. The benomyl treatment reduced the colonization to 1200 and to 400 propagules per cm² in 1972 and 1973, respectively, which implied an apparent reduction of the antagonistic capacity of the mycoflora. In 1974, the saprophytic colonization of the water-sprayed leaves reached only 500 propagules per cm² just after flowering, a population density not high enough to be antagonistic. Benomyl had a differential effect on the phyllosphere fungi:Cryptococcus spp. were not affected,Sporobolomyces roseus andCladosporium spp. were reduced to less than 6% of the control populations, andAureobasidium pullulans was eliminated. When later in the seasons of 1972 and 1974 the white yeasts on the benomyl-sprayed leaves reached population densities of 6500 propagules per cm² and more, inoculation of these leaves resulted in a necrosis similar to that of the water-sprayed leaves with higher population densities. Above a population density of 6500 propagules per cm² no correlation existed between the density of the antagonists and their action onC. sativus.Samenvatting In veldproeven werden roggebladeren, voor de bloei en op verschillende tijdstippen na de bloei, geïnoculeerd metCochliobolus sativus (Helminthosporium sativum) teneinde het antagonisme tegen dit pathogeen door de van nature voorkomende schimmelflora —inclusief gisten—te bestuderen. Eerder uitgevoerde kasproeven hebben aangetoond dat saprofytische fyllosfeerschimmels met succes met perthotrofe pathogene schimmels wedijveren om de voedingsstoffen die vrijkomen uit het stuifmeel (Warren, 1972b; Fokkema, 1973).Verschillende niveaus van saprofytische bladkolonisatie werden verkregen door de proefveldjes met benomyl of met water te behandelen (Fig. 1).C. sativus is relatief weinig gevoelig voor benomyl. Het gemiddeld percentage necrotisch bladoppervlak ten gevolge van inoculatie metC. sativus vlak na de bloei was in 1972 en in 1973 ruim 60% lager op met water behandelde bladeren dan op met benomyl behandelde bladeren (Fig. 2). Op dit moment heeft de natuurlijke schimmelflora op de met water bespoten bladeren een populatiedichtheid bereikt van 10000 propagula per cm² bladoppervlak in 1972 en van 3000 propagula per cm² in 1973. Benomylbespuiting beperkte de kolonisatie tot 1200 en 400 propagula per cm² in respectievelijk 1972 en 1973, hetgeen blijkbaar een reductie van de antagonistische capaciteit van de schimmelflora tot gevolg had. In 1974 bereikte de saprofytische kolonisatie op de met water behandelde bladeren, vlak na de bloei, slechts een niveau van 500 propagula per cm², hetgeen niet genoeg bleek om antagonistisch te kunnen zijn.Benomyl had een gedifferentieerd effect op de aantallen fyllosfeerschimmels:Cryptococcus spp. (witte gisten) werden niet nadelig beïnvloed,Sporobolomyces roseus (rode gisten) enCladosporium spp. werden gereduceerd tot minder dan 6% van hun populaties op de contrôle bladeren, enAureobasidium pullulans werd geëlimineerd (Tabel 1). De bacterieflora varieerde enorm per blad en werd niet door benomyl beinvloed.Wanneer later in het seizoen in 1972 en in 1974 de witte gisten op de met benomyl bespoten bladeren populatiedichtheden bereikten van 6500 propagula/cm² of meer, dan was de infectie van deze bladeren vergelijkbaar met die van de met water behandelde bladeren met hogere populatiedichtheden (Fig. 2). Boven een populatiedichtheid van 6500 propagula/cm² bestond er geen correlatie meer tussen de dichtheid van de antagonisten en hun werking.  相似文献   

Effect of 6-azauracil on infection with tobacco mosaic virus     

Jeanne Dijkstra  J. J. S. van Rensen 《European journal of plant pathology / European Foundation for Plant Pathology》1968,74(6):193-201

6-Azauracil caused a marked reduction in the number and size of local lesions on excisedNicotiana glutinosa leaves or leaf discs inoculated with tobacco mosaic virus or its nucleic acid. The amount of infectivity recovered from tobacco (N. tabacum White Burley) leaf discs floated on the pyrimidine analogue solution and subsequently ground and assayed 24, 48, 72, and 96 h after inoculation with intact virus was reduced in the 24, 48, and 72 h series but reached the same level as that of the water-treated control discs in the 96 h series.By contrast, the amount of infectivity in stripped epidermal tissue ofN. glutinosa leaves inoculated with nucleic acid was not reduced in strips floated on the analogue for 24, 50, and 70 h as compared with water-floated controls. The analogue had no effect on infectivity of the virus in vitro and did not act as an inhibitor of infection.Part of this paper was presented at the International Symposium on Plant Pathology, held in New Delhi from December 27, 1966 till January 1, 1967. A summary will be published in the symposium volume entitled Plant disease problems.  相似文献   

BTH处理对甜瓜叶片活性氧代谢的诱导作用     

陈年来  张玉鑫  王春林  代春艳  张建农  王晓巍 《植物保护学报》2011,38(6):499-505

为了明确活性氧（reactive oxygen species,ROS）代谢在甜瓜抗病性诱导中的作用,以抗白粉病甜瓜品种Tam Dew和感病品种卡拉克赛幼苗为材料,通过盆栽试验研究了苯丙噻二唑（BTH）喷雾或白粉菌接种后甜瓜叶片超氧阴离子（O2.-）产生速率、过氧化氢（H2O2）含量及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、苯丙氨酸解氨酶（PAL）活性的变化。BTH处理或白粉菌接种均可诱导甜瓜叶片SOD、PAL活性升高,抑制CAT活性,导致叶组织O2.-产生速率和H2O2含量增加,BTH喷雾＋白粉菌接种比二者单独处理效果更好。结果表明,BTH处理后叶片O2.-产生速率提高和H2O2积累是甜瓜抗白粉病能力提高的重要机制,BTH通过诱导ROS代谢酶活性调节H2O2含量,且BTH诱导的甜瓜抗病性与品种的基础抗性有关。  相似文献