首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Several applications of the suppressive fungus MKP5111B, isolated from the phylloplane of rice plants, were tested in an effort to control rice blast disease. Three treatments with MKP5111B [living (Std), killed with liquid nitrogen (FR), and autoclaved (AC)] were either sprayed onto rice seedlings or mixed into seed-sown soil. Three weeks after spraying and 4 weeks after the soil application, we introduced Magnaporthe oryzae, the causal agent of rice blast, into our systems. The Std and FR treatments suppressed rice blast, but the AC treatment proved ineffective. Although a suppressive effect was seen on new leaves, no mycelium of MKP5111B was seen. The fungus thus may have induced a systemic resistance in the rice plants. A substance from MKP5111B, such as elicitor molecule(s) are likely responsible for the induced resistance.  相似文献   

2.
The virulence structure of theMagnaporthe grisea rice population from the northwestern Himalayan region of India was deciphered on 24 rice genotypes harboring different blast resistance genes. Matching virulences appropriate to all the rice genotypes, except Fukunishiki (Pi-z, Pi-sh) and Zenith (Pi-z, Pi-a, Pi-i), were present in the pathogen population. Moreover, a very low percentage of isolates were virulent on Tetep (Pi-ta, Pi-k h, Pi-4b) and Tadukan (Pi-ta/Pi-ta 2). Although virulence was recorded on most of the lines tested, none was susceptible to all of the isolates. Three pairs of genotypes, namely, C101LAC:C101A51; K-1: Dular; and Dular: HPU-741, exhibited complementary resistance spectra as no isolate combined virulence to both the members of each of the three pairs of genotypes despite the fact that individual members were susceptible to a major portion of the pathogen population. The blast resistance genesPi-z, Pi-k h, Pi-l andPi-2 and their various combinations were construed to provide broad spectrum and durable blast resistance in Himachal Pradesh. Pathotype analysis revealed the existence of extremely high pathotypic diversity in the pathogen population. Based on the observed population structure forM. grisea, it was not possible to designate a minimum set of pathogen isolates that could be used in blast resistance screens to identify effective sources of blast resistance. The overall results suggested that the pathotype analysis alone is insufficient to describe the existing pathogenic variability, especially when this information has to be used for guiding the breeding programs aimed at developing durable blast resistance. However, population genetics approach of studying pathogenic specialization by monitoring the frequency of individual virulence genes and analyzing virulence gene combinations for their association or dissociation might generate useful information for developing durable blast resistance. http://www.phytoparasitica.org posting May 14, 2006.  相似文献   

3.
The japonica rice (Oryza sativa) cultivar Chubu 32 has a high level of partial resistance to blast, which is mainly controlled by a dominant resistance gene located on chromosome 11. The partial resistance to the rice blast fungus (Magnaporthe grisea) in Chubu 32 has isolate specificity; isolate IBOS8-1-1 is more aggressive on Chubu 32 than are other isolates. We hypothesized that the gene-for-gene relationship fits this case of a partial resistance gene in Chubu 32 against the avirulence gene in the pathogen. The partial resistance gene in Chubu 32 was mapped between DNA markers C1172 (and three other co-segregated markers) and E2021 and was designated Pi34. In the 32 F3 lines from the cross between a chromosome segment substitution line (Pi34−) from Koshihikari/Kasalath and Chubu 32, the lines with high levels of partial resistance to the M. grisea isolate Y93-245c-2 corresponded to the presence of Pi34 estimated by graphic genotyping. This indicated that Pi34 has partial resistance to isolate Y93-245c-2 in compatible interactions. The 69 blast isolates from the F1 progeny produced by the cross between Y93-245c-2 and IBOS8-1-1 were tested for aggressiveness on Chubu 32 and rice cultivar Koshihikari (Pi34−). The progeny segregated at a 1 : 1 ratio for strong to weak aggressiveness on Chubu 32. The results suggested that Y93-245c-2 has one gene encoding avirulence to Pi34 (AVRPi34), and IBOS8-1-1 is extremely aggressive on Chubu 32 because of the absence of AVRPi34. This is the first report of a gene-for-gene relationship between a fungal disease resistance gene associated with severity of disease and pathogen aggressiveness.  相似文献   

4.
An antagonistic bacterium, Serratia marcescens strain B2, controlled rice blast after being sprayed onto rice phylloplane, as did the bacterial suspension when poured into rhizosphere soil of rice plants. Three days after root treatment, rice blast conidia were sprayed onto rice foliage. A week after pathogen inoculation, rice blast was suppressed and lesions caused by the pathogen decreased in size. Brown deposits were observed around sites of pathogen infection after root treatment. Induced resistance was not associated with an increase in the activitiy of peroxidase, phenylalanine ammonia lyase, tyrosine ammonia lyase, β-1,3-glucanase, β-1,4-glycosidase, N-acetylhexosaminidase or chitinase. However, lipoxygenase levels were elevated after the root treatment with strain B2 following inoculation with the pathogen. Strain B2 was not detected in rice foliage after root treatment. These data suggest that strain B2 induced resistance against rice blast caused by Pyricularia oryzae. Received 1 November 2001/ Accepted in revised form 25 January 2002  相似文献   

5.
To control rice blast effectively at the nursery stage, the absolute SiO2 content necessary for rice plants to resist blast disease was investigated using various rice cultivars and soils. Nine rice cultivars with different complete resistance genes and different degrees of partial resistance were grown on nursery soils amended with silica gel at different rates to change the SiO2 content of rice plant. The rice seedlings were then inoculated 28 days after sowing with Pyricularia grisea to estimate their blast resistance. In all rice cultivars, the number of lesions was significantly reduced when SiO2 content increased in the rice seedling; lesions were reduced to 5%–20% of the number on the seedlings grown in soil without silica gel when the seedling SiO2 content reached 5%. Additionally, the susceptibility to blast disease of rice seedlings grown on eight soils collected from different districts, with varying amounts of silica gel, was compared. The number of lesions decreased significantly when the SiO2 content in the seedlings reached 5%. These results suggest that SiO2 content of at least 5% in the rice plant can control this disease at the nursery stage under any conditions.  相似文献   

6.
BACKGROUND: It is possible that a single nucleotide polymorphism (SNP) (G143A mutation) in the cytochrome b gene could confer resistance to quinone outside inhibiting (QoI) fungicides (strobilurins) in rice blast fungus because this mutation caused a high level of resistance to fungicides such as azoxystrobin in Pyricularia grisea Sacc. and other fungal plant pathogens. The aim of this study was to survey Magnaporthe oryzae B Couch sp. nov. isolates in Japan for resistance to QoIs, and to try to develop molecular detection methods for QoI resistance. RESULTS: A survey on the QoI resistance among M. oryzae isolates from rice was conducted in Japan. A total of 813 single‐spore isolates of M. oryzae were tested for their sensitivity to azoxystrobin using a mycelial growth test on PDA. QoI fungicide resistance was not found among these isolates. The introduction of G143A mutation into a plasmid containing the cytochrome b gene sequence of rice blast fungus was achieved by site‐directed mutagenesis. Molecular diagnostic methods were developed for identifying QoI resistance in rice blast fungus using the plasmid construct. CONCLUSION: As the management of rice blast disease is often dependent on chemicals, the rational design of control programmes requires a proper understanding of the fungicide resistance phenomenon in field populations of the pathogen. Mutation of the cytochrome b gene of rice blast fungus would be specifically detected from diseased leaves and seeds using the molecular methods developed in this study. Copyright © 2009 Society of Chemical Industry  相似文献   

7.
The population structure of the rice blast fungus Pyricularia grisea was analyzed in two major rice-growing provinces of Iran using rep-PCR DNA fingerprinting. A total of 221 monoconidial isolates of the fungus was collected from 12 cultivars at ten regions during 1997–2000. Long-PCR conditions were used to amplify sequences lying between adjacent Pot2 elements. The frequencies of Pot2 lineages (isolates with 70% amplicon similarity) and haplotypes within lineages were determined. Phenetic analysis differentiated five Pot2 fingerprint lineages, designated A, B, C, D and E. The most common fingerprint group, Lineage E, was recovered from all rice cultivars sampled and was distributed throughout the region. Haplotype E6, the most common haplotype within lineage E, was recovered from almost all regions. Lineage A, the second most common lineage, was found mainly in the western part of the sampled region. Haplotype A1 was found in most sites in the western province. Lineage A occurred at relatively high frequency on the susceptible local cultivar Binam, suggesting that lineage A is specifically adapted to Binam. To test this hypothesis, 193 additional isolates were recovered from four fields at two sites separated by approximately 100 km. This second, field-specific collection of isolates contained lineages A, C, D, and E. Approximately 64% and 29% of the isolates recovered from Binam (the shared cv. at two sites) grouped into lineages A and E, respectively. The other two susceptible cultivars at these sites were infected by lineage E at frequencies of 100% and 71%. Overall, these data indicated a low level of genetic diversity in the Iranian P. grisea population similar to that reported in other countries.  相似文献   

8.
西南地区稻瘟病菌群体遗传多样性分析   总被引：3，自引：2，他引：1  
为明确西南地区稻瘟病菌Magnaporthe grisea(Hebert)Barr群体遗传结构及其多样性水平,选用13对SSR引物对来自18个县(市)的221个稻瘟病菌单孢菌株进行PCR扩增,利用最长距离法和生物学软件进行聚类分析和群体遗传多样性分析。结果显示,13对SSR引物均能扩增出一条大小相同且清晰的条带,多态位点百分率高达100%。221个菌株在0.16相异水平上可划分为13个遗传宗谱,宗谱SCL01含205个菌株,占总菌株数的92.76%,为优势宗谱;宗谱SCL02~SCL013为劣势宗谱,差异极大。在群体水平上,菌源丰富的8个区域稻瘟病菌群体的Nei’s基因多样性指数为0.2133,Shannon信息指数为0.3588,具有丰富的遗传多样性,且群体间差异较大;这8个种群基于UPGMA法大都聚为一类,种群遗传谱系与地理区域分布呈一定相关性,群体遗传多样性均值为0.2518,存在一定的遗传分化,且群体内多样性大于群体间,总遗传变异的59.37%存在于群体内。总体上,西南地区稻瘟病菌群体结构既有明显的优势宗谱,又存在许多复杂多变的特异性小宗谱,具有丰富的遗传多样性,与地理分布关系较为密切。  相似文献   

9.
Erwinia ananas, the causal agent of bacterial palea browning of rice, was transformed with bioluminescence genes to clarify their behavior on rice plants. Transformant CTB009T2 was used to inoculate rice plants, and the subsequent bioluminescence of CTB009T2 was observed using a two-dimensional luminometer. Luminous spots frequently appeared on anthers after flowering and on dead tissues such as leaf tips, lower leaf sheaths, and leaf blades. In spikelets that developed the disease symptom on the palea, luminous spots appeared 48h after flowering on stigmas, basal parts of ovaries, and lodicules. These results indicate that postflowering anthers and dead tissues on rice plants are important sites for a rapid increase in the pathogen population, and that the multiplication of the pathogen on internal tissues of spikelets after flowering is associated with the appearance of browning.  相似文献   

10.
The pathogenicity of progeny from crosses among three Chinese isolates of Magnaporthe grisea collected from rice was tested on three Japanese differentials (Ishikarishiroke, Aichiasahi, K 59) having the blast resistance genes Pii, Pia, and Pit, respectively. Monogenic control was demonstrated for avirulence to the differentials. To identify resistance genes corresponding to the avirulence genes, the resistance and susceptibility in F3 lines of the cultivars in response to the parents of the crosses were analyzed genetically. The three avirulence genes identified, designated Avr-Pii, Avr-Pia, and Avr-Pit, appear to correspond to resistance genes Pii, Pia, and Pit, respectively. The monogenic control of avirulence in the fungus and monogenic dominant resistance in rice cultivars supports a gene-for-gene relation in the Pii-, Pia-, or Pit-dependent resistance to the rice blast fungus in rice cultivars.  相似文献   

11.
We investigated the use of single primers complementary to sequences in the terminal inverted repeat (TIR) of either Pot2 or MGR586, transposable elements found in Pyricularia grisea, for DNA fingerprinting by repetitive-element-based polymerase chain reaction (rep-PCR). Under standard amplification conditions, rep-PCR with each single primer generated distinct fingerprint patterns among rice-infecting P. grisea isolates collected in Japan. With the Pot2-TIR primer, bands ranging in size from 0.2 to 8 kb and in number from 8 to 13 per isolate were amplified. Although fewer bands were amplified with the MGR586-TIR primer, this molecular technique should be more reliable to identify and classify P. grisea isolates by combining the data of fingerprint patterns from each TIR primer. In a cluster analysis based on DNA fingerprints from this rep-PCR with the Pot2-TIR primer, 10 reference isolates and 12 field isolates from Saga Prefecture in 2002 were separated into six clonal lineages. We also demonstrated that the 12 field isolates belonged to one clonal lineage. Thus, this rep-PCR method using the single primer Pot2-TIR will be useful for the analysis of the population structure of rice blast pathogens.  相似文献   

12.
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   

13.
为明确黑龙江省采集自不同年份、不同地区的稻瘟病菌Magnaporthe oryzae的育性能力和交配型分布,采用2株标准菌株GUY11(MAT1-2)和KA3(MAT1-1)对2016—2017年黑龙江省西部、东部、中部3个地区经单孢分离的241株稻瘟病菌进行育性测定,并利用PCR技术对其交配型进行检测。结果表明,黑龙江省西部、东部、中部的241株稻瘟病菌中可育性菌株比例为11.62%,其中雌性菌株、雄性菌株、两性菌株分别占1.66%、4.56%和1.25%,不能判断其性别的未知菌株占4.15%。采集自不同地区、不同年份的稻瘟病菌可育性差异均较大,西部、东部、中部地区可育性菌株出现频率分别为13.25%、7.27%和12.62%;2016年采集的稻瘟病菌可育性较高,可育性菌株出现频率为25.30%。黑龙江省稻瘟病菌群体中同时存在MAT1-1和MAT1-2两种交配型,主要以交配型MAT1-1占优势,出现频率为58.92%,交配型为MAT1-2的菌株出现频率为8.30%。不同地区稻瘟病菌的交配型亦有差异,交配型为MAT1-1的菌株在黑龙江省东部地区出现频率最高,为72.73%,在中部、西部地区的出现频率次之,分别为61.17%和46.99%。表明黑龙江省水稻种植区的稻瘟病菌同时存在2种交配型菌株,其交配型存在丰富的多态性,但其可育性及交配型分布不均衡。  相似文献   

14.
A series of experiments were performed to study the effects of silicon (Si) on rice blast development, H2O2 accumulation and lipid peroxidation in a controlled rice—Magnaporthe grisea pathosystem. Rice plants supplied with Si as a single dose immediately after pathogen inoculation (−/+Si) exhibited the same high protection against disease as plants treated continuously with Si for the whole growth period (+/+Si), with disease severity indices of 20.8% and 19.6%, respectively, which were significantly lower than that for the control treatment with no Si supplied (63.7%). A single application of Si to rice plants before inoculation (+/−Si) conferred partial protection (disease severity index of 33.3%) compared with the control treatment. Silicon induced a rapid but transient burst of H2O2 at 24 h after inoculation. The addition of Si to rice plants significantly altered the activities of catalase and lipoxygenase and the concentration of malodialdehyde (indicative of lipid peroxidation) in rice plants. We propose that rice plants may respond to Si by increased H2O2 accumulation and lipid peroxidation. In turn, these responses are linked to host defence mechanisms such as lignin production, oxidative cross-linking in the cell wall, phytoalexin production, and the hypersensitive reaction. Thus, the mechanisms of Si-stimulated plant disease protection may extend beyond its established role in physically strengthening cell walls.  相似文献   

15.
为进一步了解田间稻瘟病菌Magnaporthe oryzae群体中AVR-Pia基因的分布及变异,利用水稻单基因系IRBLa-C水稻品种对自云南省13个市(州)采集分离得到的471株稻瘟病菌菌株进行抗性基因Pia有效性测定;利用无毒基因AVR-Pia特异性标记对471株稻瘟病菌菌株进行PCR检测和测序,并分析稻瘟病菌群体中无毒基因AVR-Pia的分布及DNA结构变异;利用有效性结果和PCR检测结果对471株菌株进行反应型划分,筛选鉴定菌株;利用鉴定菌株对云南省112份地方稻种进行Pia基因鉴定。结果表明,在471株稻瘟病菌菌株中,对含有Pia基因的水稻单基因系IRBLa-C表现为抗病和感病的菌株数分别为139株和332株,所占比例分别为29.5%和70.5%;在471株稻瘟病菌菌株中,分别有244株和227株菌株含有无毒基因AVR-Pia和不含有无毒基因AVR-Pia,所占比例分别为51.8%和48.2%,无毒基因AVR-Pia主要为完全缺失变异;在471株稻瘟病菌菌株中,A-和V+反应型菌株数分别为56株和161株,共217株,占总菌株数的46.1%,在13个市(州)稻瘟病菌群体中,A-和V+反应型菌株所占比例差异较大,其中在普洱市、红河哈尼族彝族自治州、昭通市、玉溪市4个市(州)的比例较大,分别为77.8%、57.1%、52.1%和50.0%;在112份云南省地方稻种质资源中,有20份地方稻品种含有抗性基因Pia,主要分布在9个市(州)中。表明云南省13个市(州)绝大部分水稻产区水稻Pia基因已丧抗性,含Pia基因的水稻种质在云南省分布较广。  相似文献   

16.
Blast is considered the most important fungal disease of rice due to its wide distribution and destructiveness under favorable conditions. Development of new effective and environmentally benign agents against the causal pathogen, Magnaporthe oryzae, is of great interest. In the course of a search for natural antifungal compounds in medicinal plants, we found that the methanol extract of Angelica gigas roots showed a potent control efficacy against rice blast caused by M. oryzae. We isolated antifungal coumarins from the extract, and they were identified as decursin and decursinol angelate. Antifungal activities of these compounds, along with kasugamycin, were tested on M. oryzae in vivo and in vitro. In an in vivo assay, the three compounds effectively suppressed the development of rice blast at concentrations more than 100 μg/mL. Coumarins showed relatively weak inhibitory effect on fungal mycelial growth when compared to kasugamycin. However, they strongly inhibited M. oryzae spore germination, which was not observed in kasugamycin treatments. This is the first report demonstrating that decursinol angelate can provide control against rice blast and that the two coumarins inhibit M. oryzae spore germination. In addition, the wettable powder formulation of the crude extract of A. gigas prohibited the development of blast symptoms on rice plants more effectively than liquid concentrate formulation of kasugamin, a commercial fungicide. Based on our study, we propose that coumarin compounds as well as the A. gigas root crude extract can be used as natural, benign fungicides for controlling rice blast.  相似文献   

17.
Rice blast disease, caused by the filamentous fungus Pyricularia oryzae, is one of the most destructive diseases in rice worldwide. Breeding of resistant rice cultivars remains a cost-effective and environment-friendly means for controlling blast disease, but the resistance tends to break down over time because of the pathogen's rapid adaptation. In this study, AVRPiz-t gene sequences of 46 rice blast isolates were evaluated using a Southern blot analysis. The AVRPiz-t gene was present in 24 of 46 (52.2%) rice blast isolates. The pathogenicity assay showed that all blast isolates were avirulent against Japanese rice cv. Toride 1, which carries several rice blast resistance genes including Piz-t, Pii, Pi37, and Pi-ta. Screening for the Piz-t gene in Thai rice germplasm revealed that less than 20% of rice varieties harbour the Piz-t gene. Therefore, the Toride 1 rice variety could serve as an effective donor of rice blast resistance to be used in rice breeding programmes in Thailand. This study provides evidence for co-evolution between the rice blast resistance gene Piz-t and the rice blast fungal avirulence gene AVRPiz-t. Understanding this relationship will facilitate the sustainable development of breeding for rice blast resistance in the future.  相似文献   

18.
为明确云南省不同稻区稻瘟病菌Magnaporthe oryzae的毒性频率及交配型分布,利用2007—2013年分离自云南省不同稻区的112株稻瘟病菌单孢菌株,对23个持有不同抗性基因的单基因系和持有Pi57(t)的水稻渗入系IL-E1454进行致病性测定。结果表明,稻瘟病菌对不同抗病基因的毒性频率存在很大差异,分离自粳稻区的稻瘟病菌菌株对持有Piz-t、Pi5、Pi9、Pi20和Pi57(t)这5个水稻品系的毒性频率分别为14.29%、5.36%、5.51%、5.36%和0;分离自籼稻区的稻瘟病菌菌株对持有Pik-h、Piz、Pita、Piz-5、Pita-2、Pi5、Pi7和Pi9这8个水稻品系的毒性频率分别为18.25%、9.13%、9.64%、7.50%、15.72%、0、13.05%和0;分离自陆稻区的稻瘟病菌菌株菌株对持有Pik-h、Pib、Pish、Pi1、Pi5、Pi9、Pi11和Pi57(t)这8个水稻品系的毒性频率分别为6.67%、3.33%、13.79%、13.33%、7.69%、6.67%、0和3.23%;交配型测定结果显示,陆稻区菌株可交配率为100.00%,...  相似文献   

19.
A metabolomics based approach has been used to study the infection of the Hwacheong rice cultivar (Oryza sativa L. cv. Hwacheong) with compatible (KJ201) and incompatible (KJ401) strains of the rice blast fungal pathogen Magnaporthe grisea. The metabolic response of the rice plants to each strain was assessed 0, 6, 12, 24, 36, and 48 h post inoculation. Nuclear Magnetic Resonance (NMR) spectroscopy and Gas and Liquid Chromatography Tandem Mass spectrometry (GC/LC-MS/MS) were used to study both aqueous and organic phase metabolites, collectively resulting in the identification of 93 compounds. Clear metabolic profiles were observed at each time point but there were no significant differences in the metabolic response elicited by each pathogen strain until 24 h post inoculation. The largest change was found to be in alanine, which was ~30% (±9%) higher in the leaves from the compatible, compared to the resistant, plants. Together with several other metabolites (malate, glutamine, proline, cinnamate and an unknown sugar) alanine exhibited a good correlation between time of fungal penetration into the leaf and the divergence of metabolite profiles in each interaction. The results indicate both that a wide range of metabolites can be identified in rice leaves and that metabolomics has potential for the study of biochemical changes in plant-pathogen interactions.  相似文献   

20.
 粳稻品种东农415自育成以来一直以其早熟、抗病、高产特性而著称,在黑龙江省稻瘟病高发区种植20多年均表现高抗稻瘟病。本研究利用158个采集于黑龙江省不同稻区的稻瘟病菌株对东农415进行接种鉴定,结果表明东农415对黑龙江省稻瘟病菌株有很强的抗性,抗谱高达89.2%。以东农415与丽江新团黑谷(LTH)杂交衍生的F1和F2群体为遗传分析试验材料,通过接种鉴定,发现东农415对稻瘟病菌株F-10-11的抗性由一个显性基因控制。进一步采用分子标记结合隐性群体分离分析法,以对菌株F-10-11极端感病的99个F2单株为作图群体,将东农415的抗病基因定位在第2染色体,距离基因两侧标记RM5300和RM213的遗传距离分别为7.6和3.0 cM,暂命名为Pi-dn(t)。将Pi-dn(t)位点映射到水稻参考基因组图谱上,在抗病位点基因组区段内发现3个编码基因Os02g56010、Os02g55540和Os02g56400具有抗病基因结构域,可作为Pi-dn(t)的候选基因。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号