共查询到20条相似文献,搜索用时 353 毫秒
1.
Pamela Paparu Thomas Dubois Danny Coyne Altus Viljoen 《Physiological and Molecular Plant Pathology》2007,71(4-6):149-157
2.
Kenji Hirata Yukio Tosa Hitoshi Nakayashiki Shigeyuki Mayama 《Journal of General Plant Pathology》2005,71(5):340-344
We examined whether PWT4, an avirulence gene of Avena isolates of Magnaporthe oryzae toward wheat, corresponded to Rwt4, a resistance gene identified in wheat cultivar Norin 4, in a one-to-one manner. Twelve wheat cultivars were inoculated with 65X1, an F1 culture with PWT4 derived from a cross between an Avena isolate (Br58) and a Triticum isolate (Br48). Three wheat cultivars (Norin 26, Shin-chunaga, Cheyenne) were resistant and therefore selected as possible carriers of Rwt4. The three cultivars were then inoculated with a population derived from a backcross of 61M2 carrying PWT4 with Br48 carrying pwt4. Segregation analyses revealed that PWT4 operates against the three cultivars. If PWT4 corresponds to Rwt4 in a one-to-one manner, all three cultivars should carry Rwt4. To test if this is the case, the three cultivars were crossed with Chinese Spring (a noncarrier of Rwt4) and Norin 4. When F2 seedlings from Chinese Spring × Norin 26, Chinese Spring × Shin-chunaga, and Chinese Spring × Cheyenne were inoculated with 61M2, resistant and susceptible seedlings segregated in a 3 : 1 ratio. On the other hand, crosses between the three cultivars and Norin 4 yielded no susceptible F2 seedlings. These results indicate that all three cultivars carry Rwt4. Considering all results, we concluded that PWT4 corresponds to Rwt4 in a one-to-one manner. An inoculation test with Chinese Spring–Cheyenne chromosome substitution lines indicated that Rwt4 is located on chromosome 1D. 相似文献
3.
Adhikari TB Cavaletto JR Dubcovsky J Gieco JO Schlatter AR Goodwin SB 《Phytopathology》2004,94(11):1198-1206
ABSTRACT Breeding wheat for resistance is the most effective means to control Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola (anamorph Septoria tritici). At least eight genes that confer resistance to STB in wheat have been identified. Among them, the Stb4 locus from the wheat cv. Tadinia showed resistance to M. graminicola at both seedling and adult-plant stages. However, no attempt has been made to map the Stb4 locus in the wheat genome. A mapping population of 77 F10 recombinant-inbred lines (RILs) derived from a three-way cross between the resistant cv. Tadinia and the susceptible parent (Yecora Rojo x UC554) was evaluated for disease resistance and molecular mapping. The RILs were tested with Argentina isolate I 89 of M. graminicola for one greenhouse season in Brazil during 1999, with an isolate from Brazil (IPBr1) for one field season in Piracicaba (Brazil) during 2000, and with Indiana tester isolate IN95-Lafayette-1196-WW-1-4 in the greenhouse during 2000 and 2001. The ratio of resistant:susceptible RILs was 1:1 in all three tests, confirming the single-gene model for control of resistance to STB in Tadinia. However, the patterns of resistance and susceptibility were different between the Indiana isolate and those from South America. For example, the ratio of RILs resistant to both the Indiana and Argentina isolates, resistant to one but susceptible to the other, and susceptible to both isolates was approximately 1:1:1:1, indicating that Tadinia may contain at least two genes for resistance to STB. A similar pattern was observed between the Indiana and Brazil isolates. The gene identified with the Indiana tester isolate was assumed to be the same as Stb4, whereas that revealed by the South American isolates may be new. Bulked-segregant analysis was used to identify amplified fragment length polymorphism (AFLP) and microsatellite markers linked to the presumed Stb4 gene. The AFLP marker EcoRI-ACTG/MseI-CAAA5 and microsatellite Xgwm111 were closely linked to the Stb4 locus in coupling at distances of 2.1 and 0.7 centimorgans (cM), respectively. A flanking marker, AFLP EAGG/ M-CAT10, was 4 cM from Stb4. The Stb4 gene was in a potential supercluster of resistance genes near the centromere on the short arm of wheat chromosome 7D that also contained Stb5 plus five previously identified genes for resistance to Russian wheat aphid. The microsatellite marker Xgwm111 identified in this study may be useful for facilitating the transfer of Stb4 into improved cultivars of wheat. 相似文献
4.
Deanna L. Funnell Christopher B. Lawrence Jeffrey F. Pedersen Christopher L. Schardl 《Physiological and Molecular Plant Pathology》2004,65(6):285-296
Systemic acquired resistance (SAR) is induced following inoculation of Peronospora tabacina sporangia into the stems of Nicotiana tabacum plants highly susceptible to the pathogen. Previous results have shown that accumulation of acidic β-1,3-glucanases (PR-2's) following induction of SAR by P. tabacina may contribute to resistance to P. tabacina. We showed that up-regulation of the PR-2 gene, PR-2d, following stem inoculation with P. tabacina, is associated with SAR. Studies using plants transformed with GUS constructs containing the full length promoter from PR-2d or promoter deletions, provided evidence that a previously characterized regulatory element that is involved in response to salicylic acid (SA), may be involved in regulation of PR-2d following induction of SAR with P. tabacina. This work provides evidence that regulation of PR-2 genes during P. tabacina-induced SAR may be similar to regulation of these genes during infection of N-gene tobacco by TMV or following exogenous application of SA, and provides further support for the role of SA in regulation of genes during P. tabacina-induced SAR. 相似文献
5.
Pathogen development and host responses in wheat spikes of resistant and susceptible cultivars infected by Fusarium culmorum causing Fusarium head blight (FHB), were investigated by means of electron microscopy as well as immunogold labelling techniques. The studies revealed similarities in the infection process and the initial spreading of the pathogen in wheat spikes between resistant and susceptible cultivars. However, the pathogen’s development was obviously more slow in the resistant cultivars as in comparison to a susceptible one. The structural defence reactions such as the formation of thick layered appositions and large papillae were essentially more pronounced in the infected host tissues of the resistant cultivars, than in the susceptible one. β -1,3-glucan was detected in the appositions and papillae. Furthermore, immunogold labelling of lignin demonstrated that there were no differences in the lignin contents of the wheat spikes between susceptible and resistant cultivars regarding the uninoculated healthy tissue, but densities of lignin in host cell walls of the infected wheat spikes differed distinctly between resistant and susceptible cultivars. The lignin content in the cell walls of the infected tissues of the susceptible wheat cultivar increased slightly, while the lignin accumulated intensely in the host cell walls of the infected wheat spikes of the resistant cultivars. These findings indicate that lignin accumulation in the infected wheat spikes may play an important role in resistance to the spreading of the pathogen in the host tissues. Immunogold labelling of the Fusarium toxin DON in the infected lemma showed the same labelling patterns in the host tissues of resistant and susceptible cultivars. However, there were distinct differences in the toxin concentration between the tissues of the susceptible and resistant cultivars. At the early stage of infection, the labelling densities for DON in resistant cultivars were significantly lower than those in the susceptible one. The present study indicates that the FHB resistant cultivars are able to develop active defence reactions during infection and spreading of the pathogen in the host tissues. The lower accumulation of the toxin DON in the tissues of the infected spikes of resistant cultivars which results from the host’s defence mechanisms may allow more intensive defence responses to the pathogen by the host. 相似文献
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7.
Barley yellow dwarf (BYD) is one of the main viral diseases of small-grain cereals. This disease, reported on numerous plant
species of the Poaceae family, is caused by a complex of eight viral species including the species Barley Yellow Dwarf Virus-PAV (BYDV-PAV), frequently found in western Europe. Resistance sources against BYDV-PAV are scarce and only identified in perennial
Triticineae. Some BYDV-resistant wheat lines have been obtained by introgressing these resistances into bread wheat germplasms. Genetic
and biological characterization of the resulting lines has been undertaken. However, little information on the resistant behaviour
of these lines during the early stages of the infection process is available. To evaluate the resistance of two genetically
distinct resistant lines (Zhong ZH and TC14), 1740 young plantlets, belonging to susceptible reference hosts (barley cv. Express and wheat cv. Sunstar), Zhong ZH or TC14 wheat lines, were inoculated in controlled conditions with French BYDV-PAV isolates. The infection process was monitored
during the first 21 days after inoculation (DAI) using a semi-quantitative ELISA. A standardized protocol including five successive
samplings of leaves from all inoculated plants and the collection of plant roots at the end of the monitored period was carried
out. This protocol enabled an assessment of the infection percentage and the evolution of the viral load in plants from the
7th DAI to the 21st DAI. Statistical analyses of the BYDV infection kinetics using raw ELISA data, a model of the time-dependent
variation of the percentage of infected plants and the area under concentration progress curves (AUCPC) demonstrated that
Zhong ZH and TC14 lines (1) reduce the development rate of the BYD disease during the first days of infection, (2) decrease the infection efficiency
of BYDV-PAV isolates, in the leaves, from 98.7% for susceptible plant genotypes to 81.9% and 71.7% for Zhong ZH and TC14, respectively, (3) reduce the virus load in the leaves of infected plants and (4) are not spared from BYDV infection, as
95.1% of Zhong ZH and 90.2% of TC14 inoculated plants accumulated viral particles in roots and/or in leaves at 21 DAI. These results confirm the BYDV-partial
resistant behaviour of both Zhong ZH and TC14 lines. The development rate of the disease was the single parameter that allowed the distinction between the two resistant
sources present in the tested lines. 相似文献
8.
Early molecular signatures of responses of wheat to Zymoseptoria tritici in compatible and incompatible interactions
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Zymoseptoria tritici, the causal agent of septoria tritici blotch, a serious foliar disease of wheat, is a necrotrophic pathogen that undergoes a long latent period. Emergence of insensitivity to fungicides, and pesticide reduction policies, mean there is a pressing need to understand septoria and control it through greater varietal resistance. Stb6 and Stb15, the most common qualitative resistance genes in modern wheat cultivars, determine specific resistance to avirulent fungal genotypes following a gene‐for‐gene relationship. This study investigated compatible and incompatible interactions of wheat with Z. tritici using eight combinations of cultivars and isolates, with the aim of identifying molecular responses that could be used as markers for disease resistance during the early, symptomless phase of colonization. The accumulation of TaMPK3 was estimated using western blotting, and the expression of genes implicated in gene‐for‐gene interactions of plants with a wide range of other pathogens was measured by qRT‐PCR during the presymptomatic stages of infection. Production of TaMPK3 and expression of most of the genes responded to inoculation with Z. tritici but varied considerably between experimental replicates. However, there was no significant difference between compatible and incompatible interactions in any of the responses tested. These results demonstrate that the molecular biology of the gene‐for‐gene interaction between wheat and Zymoseptoria is unlike that in many other plant diseases, indicate that environmental conditions may strongly influence early responses of wheat to infection by Z. tritici, and emphasize the importance of including both compatible and incompatible interactions when investigating the biology of this complex pathosystem. 相似文献
9.
Experiments were conducted to determine the effectiveness and profitability of the Mi-resistance gene in tomato in suppressing populations of Meloidogyne javanica in a plastic-house with a natural infestation of the nematode. Experiments were also conducted to test for virulence and durability of the resistance. Monika (Mi-gene resistant) and Durinta (susceptible) tomato cultivars were cropped for three consecutive seasons in non-fumigated or in soil fumigated with methyl bromide at 75 g m–2 and at a cost of 2.44 euros m–2. Nematode densities were determined at the beginning and end of each crop. Yield was assessed in eight plants per plot weekly for 6 weeks. The Pf/Pi values were 0.28 and 21.6 after three crops of resistant or susceptible cultivars, respectively. Growth of resistant as opposed to susceptible tomato cultivars in non-fumigated soil increased profits by 30,000 euros ha–1. The resistant Monika in non-fumigated soil yielded similarly (P > 0.05) to the susceptible Durinta in methyl bromide fumigated soil but the resistant tomato provided a benefit of 8800 euros ha–1 over the susceptible one because of the cost of fumigation. Selection for virulence did not occur, although the nematode population subjected to the resistant cultivar for three consecutive seasons produced four times more eggs than the population on the susceptible one. Such a difference was also shown when the resistant cultivar was subjected to high continuous inoculum pressure for 14 weeks. The Mi-resistance gene can be an effective and economic alternative to methyl bromide in plastic-houses infested with root-knot nematodes, but should be used in an integrated management context to preserve its durability and prevent the selection of virulent populations due to variability in isolate reproduction and environmental conditions. 相似文献
10.
Fusarium wilt of basil (Ocimum basilicum), caused byFusarium oxysporum f.sp.basilici, is reported for the first time in Greece. Foliage inoculation of young plants resulted in a downward movement of the pathogen
to the crown and roots and 20–30% plant mortality. Of 14 commercial basil cultivars evaluated for possible disease resistance
using young plants, six out of eight large-leaved cultivars were found resistant, while all six small-leaved ones were susceptible.
http://www.phytoparasitica.org posting Feb. 23, 2004. 相似文献
11.
Polymnia P. Antoniou Emmanouil A. Markakis Sotirios E. Tjamos Epaminondas J. Paplomatas Eleftherios C. Tjamos 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(4):549-560
An innovative inoculation process, involving the drilling of a trunk hole in 3 year-old olive trees and injecting a dense
conidial suspension of Verticillium dahliae, was developed to study differentiation in foliar symptom expression between olive cultivars tolerant or susceptible to the
pathogen. It was demonstrated that V. dahliae conidia could be translocated and colonize the xylem at the same distance above and below the point of trunk injection in
both cultivars. However, the pathogen could be subsequently isolated at statistically significant percentages in susceptible
cv. Amphissis compared to the tolerant cv. Kalamon, indicating operation of resistance mechanisms in the vascular phase of
the disease. Consequently symptom development in the susceptible cultivar was at least sixfold more intensive compared to
the tolerant cultivar, 6–11 months after trunk inoculation. Perennial olive orchard experiments, aimed at selecting Verticillium-resistant
root-stocks, were conducted by applying the novel method in 2–3 year-old root-stock suckers of Amphissis olive trees and in
the tolerant cvs Lianolia of Corfu and Koroneiki. It was indicated that potentially resistant root-stocks could be obtained
following the trunk drilling technique. Resistance differentiation between cvs Amphissis and Kalamon was further verified
through root inoculation by various V. dahliae microsclerotial concentrations and demonstrated that the trunk drilling inoculation procedure is equally efficient in resistance
evaluation of olives to Verticillium wilt. The trunk inoculation procedure could be useful in selecting and screening root-stocks
for resistance to V. dahliae and other vascular pathogens and could elucidate resistance mechanisms in woody plants against vascular wilt diseases. 相似文献
12.
为鉴定筛选兼抗麦长管蚜和大麦黄矮病毒(Barley yellow dwarf virus, BYDV)的小麦种质,采用自然感蚜/感病系数法,对36个外引和远缘杂交选育的小麦种质材料进行了2年的田间鉴定,并分析了感虫性与感病性的相关关系。结果表明,2年中均兼抗麦长管蚜和BYDV的种质仅有KOKIPPCAS、KOK、Amigo-3和PI137739共4个材料,占总鉴定材料的11.11%;对二者均敏感的有98-10-35q-9、186Tm39、Tam200e12-14a、Tam200(27)7、小偃22、西农1376和小偃6号共7个材料,占19.44%。其它材料仅抗虫或仅抗病,或仅在一年中表现抗病或抗虫,如材料98-10-30和98-10-35a8抗麦长管蚜,但对BYDV敏感;材料Tam200(13)G和PIG23(2)C感蚜,但对BYDV有抑制作用。BYDV发生普遍率(发病株率)和严重度(病情指数)与有蚜株率显著相关,严重度还与感蚜指数显著相关,但感病植株的病级均值与有蚜株率无显著相关性。表明自然界长期的进化和选择使许多抗病虫基因得以保存下来,但较多抗性基因只在抗病或抗虫的某一方面表现有效,需给予更多关注。 相似文献
13.
玉米抵御玉蜀黍尾孢菌侵入的生理机制 总被引:2,自引:0,他引:2
为深入探讨玉米抗灰斑病的机制,以抗/感玉米灰斑病自交系78599-1、OH43Ht N和掖478、K12为材料,采用比色皿法和RT-PCR法相结合研究了接种玉蜀黍尾孢菌毒素后玉米叶片中防御酶活性、丙二醛(MDA)含量及防御酶合成相关基因SOD、CAT、APX和GR的表达量。结果显示,接种该病菌毒素后,抗、感材料叶片中防御酶活性均升高,多数在接种7 d时达到峰值,且抗病材料防御酶活性峰值高于感病材料;供试材料叶片中MDA含量均降低,且抗病材料低于感病材料;供试材料叶片中SOD、CAT和GR的表达量均上升,其中CAT的表达量在78599-1、掖478和K12接种5d时达到峰值,灰度值分别为228.67、161.33和178.00,与其酶活性变化趋势一致;SOD和GR的变化规律与其酶活性变化不一致;APX的表达量仅在OH43Ht N中上升,接种7 d后达到峰值。表明抗病材料调控防御酶活性的能力强,防御酶基因的表达与其酶活性变化存在关联性。 相似文献
14.
Azadeh Ghaneie Rahim Mehrabi Naser Safaie Masoud Abrinbana Abbas Saidi Mostafa Aghaee 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(2):191-202
Septoria tritici blotch (STB), caused by Mycosphaerella graminicola has recently become one of the devastating diseases in Iran causing significant yield losses on most commercial bread and
durum wheat cultivars. Iran is located in the Fertile Crescent, a region where wheat was historically domesticated; and, thus,
landraces derived from this region are of considerable global interest for identification of new sources of resistance to
various stresses. Here, we report on the resistance responses of 45 tetraploid wheat landraces collected from different provinces
of Iran to eight M. graminicola isolates. In total 138 isolate-specific resistances were found among all interactions (n = 360). The highest number of specific resistances (30 out of 32 interactions) was found in wheat landraces collected from
West Azarbaijan. In contrast, all landraces from Kordestan were highly susceptible to M. graminicola isolates and only one isolate-specific resistance was identified among 106 isolate-wheat interactions. Kermanshah landraces
showed the highest resistance variation against different isolates. About 57 isolate-specific resistances were identified
among 104 interactions. Ilam landraces were highly resistant to STB as 28 specific resistances were observed among 32 interactions.
Markazi (n = 2) and Sistan-Baluchestan (n = 1) were susceptible to all isolates tested. Landraces from Lorestan were generally susceptible to isolates tested as 26
susceptible responses were observed out of 32 interactions. Our results indicate that landraces collected from the Fertile
Crescent region may possess diverse effective resistance genes or valuable broad spectrum resistance genes, and that their
identification is of interest and can be exploited in breeding programs. 相似文献
15.
Béatrice Denoyes-Rothan G. Guérin 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(7):615-621
Six inoculation techniques were compared for their ability to evaluate resistance toColletotrichum acutatum of five strawberry cultivars. Inoculation by dipping the whole cold stored plants in a suspension of conidia adjusted to 2.106 conidia ml–1 made it possible to screen cultivars resistant to crown rot at 28 days after inoculation. Using the dipping technique, 44 strawberry cultivars were evaluated for their resistance to one strain ofC. acutatum, 1267b. Twelve of them did not show wilt symptoms and could be classified as resistant. When another strain ofC. acutatum, 494a, was inoculated to seven cultivars, all of them including Dover, resistant to 1267b, showed wilt symptoms. This result showed the importance of investigations on genotype × isolate interactions to conduct an efficient breeding programme for screening resistance toC. acutatum. 相似文献
16.
17.
Kazutaka Kido Tomofumi Mochizuki Kazutoshi Matsuo Chika Tanaka Kenji Kubota Takehiro Ohki Shinya Tsuda 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):189-194
The single recessive gene, nsv, which confers resistance against Melon necrotic spot virus (MNSV), has recently been used to develop virus-resistant melon cultivars in Japan. However, the Chiba isolate of MNSV, a
common isolate in Japan, infected resistant cultivars when inoculated melon plants were grown at 15°C. Viral RNAs accumulated
in protoplasts from resistant cultivars at both 15 and 20°C. Mechanical inoculation of the cotyledons caused MNSV to spread
throughout the leaves at 15°C, but not at 20°C. These results support our novel hypothesis that a temperature-sensitive inactivation
of disease resistance genes occurs at the nsv locus in melon cultivars with the resistance gene grown at temperatures below 20°C.
The first and second authors contributed equally to this research. 相似文献
18.
R. Pezet K. Gindro O. Viret J.-L. Spring 《Physiological and Molecular Plant Pathology》2004,65(6):297-303
Levels of resistance to Plasmopara viticola, from susceptible to highly resistant, of different grapevine cultivars were observed in vineyards and confirmed by the symptoms developed after inoculations. On the abaxial surface of infected leaves, P. viticola developed abundant sporangiophores on susceptible cultivars (Chasselas, Gamay, Gamaret and Pinot Noir), whereas on less susceptible cultivars (Seyval Blanc and Johanniter) the parasite produced few sporangiophores and some necrotic spots at the site of infection. On resistant cultivars (Bronner, Solaris, IRAC 2091), P. viticola induced a hypersensitive response and only necrotic spots were visible and the disease ceased to develop. Stilbenes were analyzed 4, 7, 24, 48 h post-infection (hpi) on small leaf samples cut from the site of infection. Large differences were observed between the cultivars at 24 and 48 hpi. Susceptible grapevines produced resveratrol and its glycoside, piceide. In contrast, resistant plants produced high concentration of ε- and δ-viniferin. Resveratrol and piceide have little or no toxicity activity against P. viticola, whereas δ-viniferin is highly toxic and can be considered an important marker for resistance of grapevine to downy mildew. The importance of oxidative dimerization of resveratrol in comparison to the extent of its glycosylation in defense reaction of grapevines against P. viticola is discussed. 相似文献
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20.
Md. Motaher Hossain Farjana Sultana Mayumi Kubota Hiroyuki Koyama Mitsuro Hyakumachi 《Journal of General Plant Pathology》2008,74(3):213-221
The culture filtrate (CF) from the plant growth-promoting fungus Phoma sp. GS8-1 was found to induce systemic resistance in Arabidopsis thaliana against the bacterial leaf speck pathogen Pseudomonas syringae pv. tomato DC3000 (Pst), and the underlying mechanism was studied. Roots of A. thaliana were treated with CF from GS8-1, and plants expressed a clear resistance to subsequent Pst infection; disease severity was reduced, and proliferation of pathogen was suppressed. Various mutants of A. thaliana were used to test whether the CF induced resistance through one of the known signaling pathways: salicylic acid (SA), jasmonic
acid (JA), and ethylene (ET). The CF was fully protective against Pst in Arabidopsis mutants jar1 and ein2 similar to wild-type plants. However, its efficacy was reduced in plants containing transgene NahG. Examination of systemic gene expression revealed that CF modulates the expression of SA-inducible PR-1, PR-2 and PR-5 genes, the JA/ET-inducible ChitB gene, and the ET-inducible Hel gene. Moreover, the expression of these genes was further enhanced upon subsequent stimulation after attack by Pst. Our data suggest that in addition to a partial requirement for SA, the signals JA and ET may also play a role in defense
signaling in Arabidopsis. 相似文献