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1.
A quantitative multiplex real-time polymerase chain reaction (PCR) procedure was developed to assess the extent of Heterobasidion annosum (Fr.) Bref. growth in Sitka spruce (Picea sitchensis (Bong.) Carr.) bark and wood and to determine correlations between lesion length and fungal colonization. Based on lesion length and real-time PCR, the responses of four 3-year-old Sitka spruce clones to inoculation with H. annosum were characterized as showing either resistance or susceptibility to the pathogen. In susceptible clones, the extent of bark colonization did not differ from the visible length of the bark lesion, whereas lesions were longer than the extent of fungal colonization in resistant clones. The resistant clones contained considerably less fungal DNA than the susceptible clones, relative to the amount of host DNA in both the bark and the wood, indicating less resistance and more host cell death in the susceptible clones following inoculation. In both resistant and susceptible clones, fungal colonization in the wood extended beyond the visible necrotic lesion in the bark, indicating that host defense responses are weaker in wood than in bark. The spread of the pathogen in both bark and wood was less in the resistant clones than in the susceptible clones, indicating that defenses in both bark and wood of the resistant clones were superior to those in the susceptible clones. 相似文献
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Forty-one 2-year-old clones of Picea sitchensis (Bong.) Carr. from three full-sib families (14 clones from each of two families and 13 clones from a third family) were either wounded and inoculated with an isolate of Heterobasidion annosum (Fr.) Bref. or wounded without inoculation. Lesion lengths on the inner bark from the point of inoculation varied among clones 35 days after treatment. There was no relationship between lesion length and relatedness within families. Two clones (21342 and 25202) with the shortest lesions, tentatively designated as less susceptible to H. annosum, and two clones (21176 and 27166) with the longest lesions, designated more susceptible, were selected for comparison of host anatomical and chemical responses to infection. The position and structure of the ligno-suberized boundary zone (LSZ) in the bark of the clones suggested that the less susceptible clones formed thicker layers of suberized cells in the LSZ following wounding plus inoculation. No LSZ was observed in two ramets of the more susceptible Clone 27166 following wounding and inoculation with H. annosum. Compared with more susceptible genotypes, clones of P. sitchensis with low susceptibility to H. annosum had high relative proportions of (+)-alpha-pinene, (-)-beta-pinene and one unidentified terpene constituent (Unknown-15) in cortical resin sampled 25 cm from the lesions. In contrast, more susceptible clones had higher relative proportions of (-)-limonene, Unknown-16, Unknown-18 and Unknown-19. In the secondary resin produced in bark tissues surrounding the lesions, proportions of several monoterpene constituents varied; these changes included a decrease in the relative amount of beta-phellandrene and corresponding small increases in some minor constituents. The concentrations of the monoterpenes, except a few minor constituents, increased in the infected tissues. Wounding plus inoculation with H. annosum resulted in varied monoterpene responses, with distinct differences between less susceptible and more susceptible clones. In less susceptible clones, Unknown-19 increased following wounding plus inoculation, whereas in more susceptible clones, concentrations of delta-3-carene and Unknown-13 and Unknown-16 increased. Differences in both constitutive and induced resin monoterpene profiles may provide useful markers for resistance to H. annosum in selection and breeding programs. 相似文献
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We investigated the cellular responses of stem tissues of mature Scots pine (Pinus sylvestris L.) trees to inoculations with two fungal pathogens. The bark beetle vectored fungus, Leptographium wingfieldii Morelet, induced longer lesions in the bark, stronger swelling of polyphenolic parenchyma cells, more polyphenol accumulation and increased ray parenchyma activity compared with the root rot fungus, Heterobasidion annosum (Fr.) Bref., or mechanical wounding. Axial resin ducts in the xylem are a general feature of the preformed defenses of Scots pine, but there was no clear induction of additional traumatic axial resin ducts in response to wounding or fungal infection. The anatomical responses of Scots pine to pathogen infection were localized to the infection site and were attenuated away from bark lesions. The responses observed in Scots pine were compared with published studies on Norway spruce (Picea abies (L.) Karst.) for which anatomically based defense responses have been well characterized. 相似文献
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Lieutier F Brignolas F Sauvard D Yart A Galet C Brunet M van de Sype H 《Tree physiology》2003,23(4):247-256
One hundred Norway spruce (Picea abies (L.) Karst.) clones (three ramets per clone) were analyzed for phloem phenol composition and concentration before and 10 days after wound inoculation with sterile malt agar. Fifty clones (Experiment 1) belonged to the same provenance, whereas the remaining clones (Experiment 2) belonged to five provenances from three geographic areas. In Experiment 2, two additional ramets from the same clones were mass inoculated with Ceratocystis polonica (Siem.) C. Moreau to quantify the resistance of each clone. Tree response to wound inoculations was characterized by increased catechin concentration in both experiments, accompanied by increases in astringin and decreases in piceid in Experiment 1. In both experiments, we observed a diverse group of phenolic compounds whose concentrations increased (catechin, astringin) or did not vary (taxifolin glucoside) in response to wound inoculations, whereas concentrations of a homogeneous group of stilbene compounds decreased (piceid) or did not vary (isorhapontin, unidentified stilbene). In Experiment 2, provenances from the alpine and Hercynian-Carpatic areas differed from provenances from the Baltic area with respect to the relative importance of these two groups of compounds, further indicating that the two groupings of phenolic compounds structure the Norway spruce populations. Eighty days after mass inoculation, the percentage of healthy sapwood, which was taken as a measure of tree resistance, indicated that clones from the Baltic area were less resistant to mass inoculations than clones from the alpine and Hercynian-Carpatic areas. We conclude that the degree of resistance of Norway spruce trees to mass inoculations with a bark beetle-associated fungus can be predicted based on the diversity of constitutive phloem phenols and the ability to induce phenol synthesis in response to wounding. 相似文献
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Physiological and biochemical differences among Ulmus minor genotypes showing a gradient of resistance to Dutch elm disease 
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下载免费PDF全文 M. Li R. López M. Venturas J. A. Martín J. Domínguez G. G. Gordaliza L. Gil J. Rodríguez‐Calcerrada 《Forest Pathology》2016,46(3):215-228
Dutch elm disease (DED) spread across Europe and North America in the 20th century killing most natural elm populations. Today, breeding programmes aim at identifying, propagating and studying elm clones resistant to DED. Here, we have compared the physiology and biochemistry of six genotypes of Ulmus minor of variable DED resistance. Leaf gas exchange, water potential, stem hydraulic conductivity and biochemical status were studied in 5‐year‐old trees of AB‐AM2.4, M‐DV2.3, M‐DV2 × M‐CC1.5 and M‐DV1 and 6‐year‐old trees of VA‐AP38 and BU‐FL7 before and after inoculation with Ophiostoma novo‐ulmi. Leaf water potential and net photosynthesis rates declined, while the percentage loss of hydraulic conductivity (PLC) increased after the inoculation in susceptible trees. By the 21st day, leaf predawn and midday water potential, stomatal conductance to water vapour and net photosynthesis rates were lower, and PLC was higher in trees of susceptible (S) genotypes inoculated with the pathogen than in control trees inoculated with water, whereas no significant treatment effect was observed on these variables in the resistant (R) genotypes. Fourier transform infrared spectroscopy analyses revealed a different biochemical profile for branches of R and S clones. R clones showed higher absorption peaks that could be assigned to phenolic compounds, saturated hydrocarbons, cellulose and hemicellulose than S clones. The differences were more marked at the end of the experiment than at the beginning, suggesting that R and S clones responded differently to the inevitable wounding from inoculation and repeated sampling over the experimental course. We hypothesize that a weak activation of the defence system in response to experimental wounding can contribute to the susceptibility of some genotypes to O. novo‐ulmi. In turn, the decline in shoot hydraulic conductivity and leaf carbon uptake caused by the infection further exacerbates tree susceptibility to the fungus. 相似文献
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Kelly vila‐Mndez Rodrigo Avila‐Diazgranados Alonso Pardo Mariana Herrera Greicy Sarria Hernan Mauricio Romero 《Forest Pathology》2019,49(2)
Bud rot (BR) disease caused by Phytophthora palmivora is the most devastating disease in oil palm cultivation in America. Oil palms that survived BR epidemics were found in areas highly devastated by the disease; these palms were introduced into Cenipalma's in vitro micropropagation (cloning programme). A severity scale was developed for in vitro palms from five ortets inoculated with two different P. palmivora isolates. Then, eight ortets of Elaeis guineensis and two ortets of the OxG interspecific hybrid were evaluated in two inoculation trials under chamber growth conditions. The clone performance response was consistent with that reported in the field for the corresponding ortets, and two contrasting ortets, one susceptible (ortet 57) and one resistant (ortet 34) were identified. We monitored and compared defence responses to P. palmivora in the contrasting ortets. An increase in reactive oxygen species (ROS) production after inoculation with the pathogen was observed, with higher accumulation of H2O2 in the resistant plants. Catalase (CAT) activity in resistant plants increased after inoculation with the pathogen from 24 hr post‐infection (hpi) and remained high during the observation time. In the susceptible ortets, there was a significant increase on catalase activity only at 48 hpi. Peroxidase (POS) activity increased in clones from both susceptible and resistant ortets, but the increase was much greater in the susceptible ones. Phenylalanine ammonia lyase activity increased in response to inoculation, and these increases were greater in clones of the susceptible ortet than in clones of the resistant ortet. 相似文献
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We compared growth rates among mature interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) trees showing resistance or susceptibility to defoliation caused by western spruce budworm (Choristoneura occidentalis Freeman), and among clones and half-sib seedling progeny of these trees in a greenhouse. We also investigated bud burst phenology and photosynthetic responses of clones to budworm defoliation in greenhouse experiments. Resistant mature trees had a higher radial growth rate than susceptible trees, especially during periods of budworm defoliation. Clones from resistant trees grew larger crowns than clones from susceptible trees, whereas stem base diameter at the ground line and height did not differ. Half-sib seedling progeny from resistant trees had larger stem diameter, height, and total biomass than progeny from susceptible trees. Mean 5-year radial growth increment of mature trees was more strongly correlated with growth of seedlings than with growth of clones. Clones from resistant trees had later bud burst than clones from susceptible trees, and budworm defoliation of clones depended on the degree of synchrony between bud burst phenology and budworm larval feeding. Clones of resistant and susceptible mature trees showed similar responses of net photosynthetic rate to 2 years of budworm defoliation. We conclude that phenotypic differences in crown condition of Douglas-fir trees following western spruce budworm defoliation are influenced by tree genotype and that high growth rate and late bud burst phenology promote tree resistance to budworm defoliation. 相似文献
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Ramets derived from root sprouts of two quaking aspen (Populus tremuloides) parents were either mechanically wounded or wounded and inoculated with mycelium of Hypoxylon mammatum. Female aspen parents were considered either resistant or susceptible based on a 30-year field trial of their open-pollinated progenies that had 21% and 93% mortality, respectively, caused by H. mammatum. Each stem was wounded twice at the base and in the nonlignified zone. Samples were taken 5 mm above the site of wounding at 7 and 14 days. Histochemicals used were phloroglucinol-HCl and Sudan Black B to detect lignin and suberin, respectively. Thin sections of the resistant aspen ramets showed intensive staining phloroglucinol-HCl, which was localized along both sides of the wound margin. Collenchyma callus was well developed by day 7 and was derived from the phloem tissue internal to the cell walls staining positive for phloroglucinol-HCl, near the vascular cambium. In contrast, the tissues of susceptible aspen ramets were less stained, the stained cells were less scattered and less collenchyma callus had formed than on the resistant ramets. The presence of the fungus increased the amount of staining observed with phloroglucinol-HCl and delayed wound closure in both aspen genotypes. No distinguishing pattern could be identified between the two aspen genotypes with respect to suberin formation. When comparing stem response to phloroglucinol-HCl with respect to the tissue type on the same stem (succulent versus woody), the inoculation of older woody tissue resulted in a more defined host response and thus were better in separating the two aspen genotypes. 相似文献
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The fungus Sphaeropsis sp. is reported for first time in Greece to cause cankers on Cupressus sempervirens. The cultural characteristics on PDA, spore shape and size and canker morphology were identical to those of the fungus described as Diplodia pinea f. sp. cupressi in Israel. The cankers of Sphaeropsis sp. are characterized by resin exudation, with fissuring of the bark over a dry sector of the wood. The pathogenicity of the Sphaeropsis sp. was proved by artificial inoculations on selected cypress clones resistant and susceptible to Seiridium cardinale. The mean canker length of the susceptible clone was significantly more than that of the resistant clones. It appears that the defence reaction in cypress against both fungi is similar. In artificial inoculations on Pinus halepensis and Pinus pinea, Sphaeropsis sp. was nonpathogenic. During a 3‐year period, in an experimental plot in western Peloponnese, the fungus spread from one, initially, to 13 cypress clones. Drought stress during the summer appears to be the main factor predisposing the cypress plants to become susceptible to the fungus. 相似文献
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Resistance of elms (Ulmus spp.) to the pathogenic fungus Ophiostoma novo-ulmi Brasier depends on chemical and anatomical factors that confine the spread of the pathogen in the vascular system of the host. This study focused on detecting chemical differences in 4-year-old Ulmus minor Mill. seedlings before and after inoculation with a virulent O. novo-ulmi isolate. According to symptom development over 60 days, the trees were divided into resistant (0-33% wilting) and susceptible (67-100% wilting) groups. Histochemical tests and Fourier transform-infrared (FT-IR) spectroscopy analysis were performed on transverse sections of 2-year-old twigs, 2 days before and 40 days after inoculation. Although histochemical tests did not clearly discriminate susceptible from resistant elms, chemical differences between resistant, susceptible and control trees were detected by FT-IR. The average spectrum for resistant tree samples had higher absorbance peaks than the spectra from the susceptible and control samples, indicating increased formation of lignin and suberin. The roles of lignin and suberin in the resistance of the elms against O. novo-ulmi and the usefulness and sensitivity of the FT-IR technique for analyzing metabolic changes caused by pathogens in plants are discussed. 相似文献
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Bon MC 《Tree physiology》1988,4(4):381-387
Shoot apex proteins from 11 seedlings, two juvenile clones and three mature grafted clones of Sequoiadendron giganteum (Lindl.) Buchh. were examined throughout the year by SDS-polyacrylamide gel electrophoresis. A membrane-associated protein known as J 16, with an approximate molecular weight of 16 kD, was always detected in juvenile tissue, but was absent in tissue of the mature clones. The J 16 protein was also present in extracts of a mature clone that had been morphologically rejuvenated by micrografting. Protein extracts from the rejuvenated clone, were separated by electrophoresis and assayed for J 16 using an immunoblotting procedure with anti-J 16 serum. This test revealed two bands, J 16 and another protein with a lower molecular weight. The small molecular weight protein was not detected in juvenile clones. 相似文献
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磷酸葡萄糖脱氢酶和苯丙氨酸解氨酶与抗松针褐斑病的关系 总被引：9，自引：0，他引：9
松针褐斑病（Ｌｅｃａｎｏｓｔｉｃｔａａｃｉｃｏｌａ）是我国南方重要病害。在湿地松（Ｐｉｎｕｓｅｌｌｉｏｔｔｉｉ）抗褐斑病选育研究的基础上对湿地松针叶中的６－磷酸葡萄糖脱氢酶和苯丙氨酸解氨酶与抗病性的关系进行了研究分析。结果表明二年生健康针叶的６－磷酸葡萄糖脱氢酶的活性水平与针叶的抗病性有密切关系。在测定的１３个无性系和单株中，４个易感株的酶活性较低，９个抗病无性系中除个别酶活性与易感株相近外，其余无性系的酶活性和比活性都明显比易感株高。苯丙氨酸解氨酶的株间差异相对较小，但在总体水平上，抗病无性系的酶活性和比活性也比易感株略高。用松针褐斑病菌毒素液处理后，无论是抗病针叶还是易感针叶，６－磷酸葡萄糖脱氢酶的活性均呈上升趋势，升幅为０．５—１倍，但苯丙氨酸解氨酶的活性在用毒素处理后无明显变化。 相似文献
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The European common ash (Fraxinus excelsior) is currently threatened by a pathogenic fungus, Hymenoscyphus pseudoalbidus, which seems to enter the trees through the leaves. Continuous assessments of 39 clones in Danish field trials have shown that there are significant differences in the susceptibility of clones to the new disease. Interestingly, clones that showed early leaf senescence in the autumn were in general less susceptible to the disease than late‐senescing clones. Thus, variation in susceptibility could be owing to phenological differences associated with the infection biology. To test whether differences in susceptibility are driven by genetically based factors other than phenology, we compared inoculations with H. pseudoalbidus on four highly susceptible clones with those of four less susceptible clones. Development of necrosis was hereafter followed regularly. The growth of the fungus in the inner bark was further detected with species‐specific PCR primers. The severity of the response to infection shows significant differentiation among clones and significant correlation with clone susceptibility, as assessed from natural infections in field trials. The fungus was detected in tissues immediately surrounding the necrosis but showed some signs of endophytic growth. The results suggest that healthier clones are able to limit the growth and spread of the fungus and thereby minimize the occurrence of symptoms. This gives hope for the future preservation of F. excelsior in Europe through selection and breeding. 相似文献
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When conifers such as Picea abies Karst. (Norway spruce) are attacked by insects or pathogens, they often respond by producing increased quantities of terpenoid oleoresin. This response can be mimicked in young P. abies seedlings by treatment with methyl jasmonate (MJ). In this study, we determined the effects of MJ on terpenoids and other chemical defenses of mature P. abies, and investigated whether this treatment protected trees against attack by the blue-stain fungus Ceratocystis polonica (Siem.) C. Moreau, the most important fungal associate of the spruce bark beetle Ips typographus L. Methyl jasmonate treatment induced the formation of traumatic resin ducts in the developing xylem, enhanced resin flow and stimulated increased accumulation of monoterpenes, sesquiterpenes and diterpene resin acids. However, only minor changes were detected in terpene composition in response to MJ treatment and no changes in soluble phenolic concentration were measured. There was much variability in the timing and degree of response to MJ among clones. The observed chemical and anatomical changes in response to MJ treatment were correlated with increased resistance to C. polonica, suggesting that terpenoid oleoresin may function in defense against this pathogen. 相似文献
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通过接种青枯菌与非病原的大肠杆菌,对2个桉树无性系和1种非寄主树木的根表吸附菌量及根内含菌量进行测定.结果表明:青枯菌对感病寄主根表的吸附量多于对抗病寄主和非寄主根表的吸附量,对感病寄主根部的侵入量多于对抗病寄主但少于对非寄主根部的侵入量;病原菌较非病原菌对感病寄主根表的吸附量大,但二者对感病寄主根部的侵入量则依据根部伤口的有无而互有高低.青枯菌接种24 h内,感病寄主根表吸附菌量和根内含菌量呈上升趋势,在抗病寄主及非寄主根表的吸附菌量和根内含菌量却呈下降趋势.从统计学上看,青枯菌对寄主根部的吸附和侵入都显示出了一定的选择性,但由于病原细菌能够大量地吸附和侵入抗病寄主和非寄主根部,非病原细菌也能够大量地吸附和侵入桉树根部,因此这种选择性的生物学意义不大,青枯菌对桉树根表没有表现出明显的识别行为. 相似文献