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1.
由稻瘟病菌引起的稻瘟病是全球最严重的植物真菌病害之一, 严重威胁水稻生产安全?效应蛋白是病原菌与植物对抗过程中分泌产生的一种蛋白质, 可作为毒力因子促进侵染或作为无毒因子触发防御反应?本研究对实验室前期筛选到的在稻瘟病菌侵染早期诱导表达的效应蛋白(infection-induced expression effector protein 1, MoIEEP1)进行了功能验证与分析?结果表明: MoIeep1 在稻瘟病菌侵染初期8 h表达量最高; 信号肽和亚细胞定位分析验证该蛋白N端含有17个氨基酸的信号肽且在水稻原生质体中呈明亮点状的定位信号, 初步推测该定位信号为过氧化物酶体或线粒体等细胞器; 与野生型菌株Guy11相比, MoIeep1 基因敲除突变体菌丝生长无明显差异, 但其致病性受到影响?以上研究结果为进一步探究该蛋白质的作用机理打下良好基础, 也为揭示其他效应蛋白在稻瘟病菌侵染水稻过程中的功能提供新的理论依据?  相似文献   

2.
稻瘟病菌Magnaporthe oryzae严重威胁水稻的产量与质量,明确稻瘟病菌与水稻互作过程及机理,对防治稻瘟病具有重要意义。本研究利用稻瘟病菌常用致病菌株GUY11和ZB25,构建了绿色荧光蛋白GFP的过量表达菌株,并通过荧光显微观察菌株侵染寄主水稻过程中侵染结构的形成与发育,包括孢子萌发、附着胞形成、侵染钉形成、侵染菌丝增殖、坏死斑形成及产孢。另外,通过比较过量表达菌株对稻瘟病高抗水稻和易感水稻的侵染过程,发现侵染过程的差异主要集中于侵染钉的穿透和侵染菌丝的定殖。本研究为分析稻瘟病菌对寄主水稻的定殖规律提供了一种有效工具。  相似文献   

3.
Pseudomonas fluorescens strain Pf1, inhibitory to the growth of the rice blast pathogen Pyricularia oryzae in vitro , was developed as a talc-based powder formulation. When rice seeds were treated with this formulation, the bacteria spread to roots, stems and leaves of the plants and protected against leaf infection by P. oryzae . When applied as a foliar spray, the bacteria survived on the leaves. The powder formulation controlled leaf blast under greenhouse conditions. In tests as a seed treatment and foliar spray in four field trials it effectively controlled the disease and increased grain yield.  相似文献   

4.
ABSTRACT Although exogenous application of silicon (Si) confers efficient control of rice blast, the probable hypothesis underlying this phenomenon has been confined to that of a mechanical barrier resulting from Si polymerization in planta. However, in this study, we provide the first cytological evidence that Si-mediated resistance to Magnaporthe grisea in rice correlates with specific leaf cell reaction that interfered with the development of the fungus. Accumulation of an amorphous material that stained densely with toluidine blue and reacted positively to osmium tetroxide was a typical feature of cell reaction to infection by M. grisea in samples from Si+ plants. As a result, the extent of fungal colonization was markedly reduced in samples from Si+ plants. In samples from Si- plants, M. grisea grew actively and colonized all leaf tissues. Cytochemi-cal labeling of chitin revealed no difference in the pattern of chitin localization over fungal cell walls of either Si+ or Si- plants at 96 h after inoculation, indicating limited production of chitinases by the rice plant as a mechanism of defense response. On the other hand, the occurrence of empty fungal hyphae, surrounded or trapped in amorphous material, in samples from Si+ plants suggests that phenolic-like compounds or phytoalexins played a primary role in rice defense response against infection by M. grisea. This finding brings new insights into the complex role played by Si in the nature of rice blast resistance.  相似文献   

5.
 稻瘟病菌(Magnaporthe oryzae)引起的稻瘟病是水稻上最重要的真菌病害之一,每年给水稻生产造成10%~30%的产量损失。从分子水平解析该病菌的致病机理,对稻瘟病防控新途径的挖掘具有重要的理论和实践指导意义。前期研究发现,转录因子MoMsn2定位于细胞质和细胞核,通过调控一系列下游基因的表达,控制稻瘟病菌的生长发育和致病性等多个生物学过程。对MoMsn2进行结构域分析,发现其含有2个核定位信号序列NLS1和NLS2、1个核输出信号序列NES和2个锌指蛋白结构域C2H2,但这些结构域的生物学功能尚不清楚。本研究通过构建结构域缺失载体和获得互补菌株的方法对5个结构域在稻瘟病菌的功能进行了分析。结果发现,同时缺失2个C2H2对MoMsn2的功能没有影响,ΔC2H2菌株的表型与野生型和全长互补菌株一致。缺失NLS1能完全恢复ΔMomsn2突变体的营养生长、菌落色素和胁迫应答;部分恢复其产孢量和致病力缺陷。缺失NES仅能部分恢复突变体的生长缺陷;而缺失NLS2完全不能恢复突变体的缺陷,其表型与突变体一致。荧光观察发现,缺失NES和NLS2改变了MoMsn2的核定位模式,而缺失C2H2和NLS1不影响MoMsn2的亚细胞定位。上述结果表明,NLS1、NLS2和NES是MoMsn2中3个重要的结构域,对MoMsn2在稻瘟病菌中行使正常的生物学功能具有重要的调控作用。  相似文献   

6.
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   

7.
乙烯信号传导途径因子OsEIL 6调控水稻抗稻瘟病反应   总被引：2，自引：0，他引：2  
稻瘟病(rice blast)是水稻生产上最严重的病害之一。抗病相关基因的挖掘对稻瘟病的防治具有重要意义。研究表明植物EIN3/EIL家族基因在抗病过程中发挥着重要作用。本研究采用RNAi技术探究OsEIL6参与的水稻抗稻瘟病反应。稻瘟菌侵染时基因表达谱检测结果表明,OsEIL6在水稻和稻瘟菌非亲和组合中受到诱导表达。稻瘟菌接种结果显示,水稻OsEIL6沉默株系和野生型植株‘TG394’相比抗性下降;实时荧光定量RT-PCR结果分析表明,OsEIL6的表达量下降导致乙烯合成途径中OsACO1和乙烯信号传导途径的OsERF063和OsERF073的转录水平下降。亚细胞定位研究发现该基因定位于水稻细胞质。OsEIL6沉默株系中ROS合成途径标记基因OsrbohA和OsrbohB的表达量均明显下调,表明该基因可能通过影响ROS的合成调控水稻抗稻瘟病反应。本研究结果将有助于进一步揭示OsEIL6参与的乙烯信号传导途径介导的水稻抗稻瘟病反应机制。  相似文献   

8.
水稻与稻瘟病菌的互作已成为研究植物与病原真菌互作的模式系统。利用RT-PCR技术检测了6个水稻品种(分别含有抗病基因Pik-s、Pita、Pit、Pi1、Pi9的近等系及回交亲本丽江新团黑谷LTH)与稻瘟病菌互作过程中多个信号相关及PR基因的表达。结果表明带有稻瘟病抗性基因Pik-s、Pita、Pit的水稻品种和LTH对稻瘟病菌#626侵染表现为亲和互作,带Pi1和Pi9的水稻品种表现为非亲和互作;稻瘟病菌接种后,亲和互作中MAPK6和MAPK12表现为上调表达,带有抗性基因Pi9的水稻品种IRBL22中BIMK2表现为上调表达。总体来看,含有不同抗病基因的水稻近等系中的PR基因对稻瘟病菌的响应较为多样,非亲和互作中在早期或早中期表现为PR基因上调表达,而亲和互作中主要在晚期上调表达,说明这些PR基因表达的时间在植物与病原互作的不同时期发挥着不同的作用。  相似文献   

9.
ABSTRACT Avirulent isolates of Pyricularia oryzae and isolates of Bipolaris sorokiniana, a nonrice pathogen, were used to suppress rice blast caused by P. oryzae. In greenhouse experiments, both fungi substantially reduced leaf blast when applied 24 h or more before the pathogen. B. sorokiniana, but not avirulent isolates of P. oryzae, systemically reduced disease in leaf 5 when applied to whole plants at the four-leaf stage. In field experiments, both fungi were able to reduce neck blast significantly. No increase in grain yield was obtained by using avirulent isolates of P. oryzae, whereas five sprays with B. sorokiniana from seedling to heading stages increased the grain yield in two of three experiments conducted at two locations in Nepal. The significant increase in yield was observed under high inoculum pressure of P. oryzae. Induced resistance is suggested to be involved in the suppression of disease.  相似文献   

10.
 稻瘟菌(Magnaporthe oryzae)是一种半腐生病原菌,该病原菌可以侵染水稻,产生稻瘟病。对于水稻与稻瘟菌的互作机制,人们已经进行了大量的研究。然而,鉴于水稻基因组相对较大且稻瘟菌生理小种众多,致使研究进展缓慢。本研究通过将稻瘟菌生理小种Y34侵染拟南芥生态型Col-0,发现Y34可以感染Col-0,从而建立Y34-拟南芥互作模型,用以探究Y34与抗白粉突变体edr1的关系。结果显示,edr1比Col-0对于稻瘟菌更敏感。之前有研究表明,降低SA含量的突变体(pad4,sid2,nim1)均可抑制edr1相关表型。接种Y34于edr1与pad4、sid2、nim1形成的双基因突变体发现,所有双突变体的感病性比edr1单突均明显降低。推测EDR1可能在拟南芥抗稻瘟菌方面起一定正调控作用,且其作用依赖于SA途径的相关基因。  相似文献   

11.
ABSTRACT To explore the potential for nontoxic crop protection technologies based on the inhibition of fungal spore adhesion, we have tested the effect of synthetic zosteric acid (p-(sulfo-oxy) cinnamic acid), a naturally occurring phenolic acid in eelgrass (Zostera marina L.) plants, on spore adhesion and infection in two pathosystems: rice blast caused by Magnaporthe grisea and bean anthracnose caused by Colletotrichum lindemuthianum. We have shown that zosteric acid inhibits spore adhesion to model and host leaf surfaces and that any attached spores fail to develop appressoria, and consequently do not infect leaf cells. Low concentrations of zosteric acid that are effective in inhibiting adhesion are not toxic to either fungus or to the host. The inhibition of spore adhesion in the rice blast pathogen is fully reversible. On plants, zosteric acid reduced (rice) or delayed (bean) lesion development. These results suggest that there is potential for novel and environmentally benign crop protection technologies based on manipulating adhesion.  相似文献   

12.
The aim of these studies was to develop a semi-selective medium to differentiate Microdochium oryzae and Pinatubo oryzae, determine the frequency of seed infection of M. oryzae, study survival of the pathogen in stored seeds, and determine the frequency of infection of seed components. To simulate epidemics of differing intensities, panicles of rice cultivars that are susceptible (IR36) and resistant (IR42 and IR46) to M. oryzae were either non-inoculated, inoculated once, twice, or three times with a conidial suspension of M. oryzae. Both M. oryzae and P. oryzae colonies were recovered from seeds and were similar in culture. A semi-selective medium developed to detect M. oryzae seed infection rates aided in differentiating M. oryzae and P. oryzae by stimulating aerial conidiogenesis of P. oryzae. The conclusions taken from these results were: (a) seeds of IR36 had higher infection of M. oryzae than of IR42 and IR46 from plants grown in the dry season, but had lower infection of M. oryzae than of IR42 and IR46 from plants grown in the wet season; (b) M. oryzae infected seeds increased with an increase in the epidemic intensity with the highest occurring after three inoculations, the least occurring with non-inoculation, and intermediate with one, or two inoculations; (c) survival of M. oryzae decreased over time in seed lots stored at 10°C and 40% relative humidity and (d) all components of the rice seeds of IR36, IR42 and IR46 lots were infected with M. oryzae with the highest frequency in the endosperm and lemma, intermediate in the basal glumes and palea, and the least in the embryo.  相似文献   

13.
Mannose-binding rice lectin (MRL), which is almost identical to the salt-induced protein SalT, binds to mannose and glucose residues. Expression of the MRL gene in response to infection with Magnaporthe oryzae, the rice blast fungus, was stronger in the incompatible interaction than in the compatible. Transgenic rice plants that constitutively over-expressed MRL strongly suppressed the growth of invasive hyphae of the fungus on leaf sheaths and the development of typical susceptible-type lesions on leaf blades, but did not affect penetration by the fungus in comparison with the wild-type. On a polycarbonate plate, purified recombinant MRL inhibited conidial attachment and appressorium formation but not conidial germination. These results suggest that MRL may play an essential role in disease resistance by suppressing development of M. oryzae in situ.  相似文献   

14.
Tsuge S  Ochiai H  Inoue Y  Oku T  Tsuno K  Kaku H  Kubo Y 《Phytopathology》2004,94(5):478-483
ABSTRACT Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, was subjected to transposon mutagenesis to generate mutants defective in pathogenicity. A novel mutant 74M913 was attenuated in virulence but retained its ability to cause the hypersensitive response in leaf blight-resistant rice and tomato. Cloning and sequence analysis revealed that the transposon in 74M913 was inserted in a gene homologous to the phosphoglucose isomerase (pgi) gene of X. axonopodis pv. citri. Growth of the mutant in a synthetic medium containing fructose or xylose as a sole carbohydrate source was much reduced, indicating the transposon disrupted pgi function. The interaction between expression of pgi and hypersensitive response and pathogenicity (hrp) genes was investigated because we had demonstrated previously that expression of hrp genes of X. oryzae pv. oryzae is induced in a synthetic medium containing xylose. However, pgi and the hrp gene (hrcU) were expressed independently. This study suggests that PGI is involved in pathogenicity of X. oryzae pv. oryzae.  相似文献   

15.
Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is associated with an impaired growth phenotype of its host fungus, Magnaporthe oryzae. In this report, we assayed the virulence and pathogenicity of MoCV1-A-infected and MoCV1-A-free M. oryzae on rice plants. MoCV1-A infection did not affect virulence-associated fungal traits, such as conidial germination and appressorium formation. However, after punch inoculation of leaves on rice plants, MoCV1-A-infected strain formed smaller lesions than the MoCV1-A-free strain did on all rice varieties tested, showing that MoCV1-A infection resulted in reduced virulence of host fungi in rice plants. In contrast, after spray inoculation of rice seedlings, in some cases, MoCV1-A-infected and MoCV1-A-free strains caused different lesion types (resistance to susceptible, or vice versa) on individual international differential rice varieties. However, we did not find any gain/loss of the fungal avirulence genes by PCR, suggesting that MoCV1-A infection can convert the pathogenicity of the host M. oryzae from avirulence to virulence, or from virulence to avirulence, depending on the rice variety. We also confirmed the correlation of these race conversion events and invasive hyphae growth of the fungi in a leaf sheath inoculation assay. These data suggested that MoCV1-A infection generally confers hypovirulence to the fungal host and could be a driving force to generate physiological diversity, including pathogenic races.  相似文献   

16.
枯草芽胞杆菌GB519是一株具有广谱抑菌活性的生防菌株。本研究利用绿色荧光蛋白标记的菌株GB519-GFP处理水稻种子、根和叶片,结合激光共聚焦显微镜观察和抗生素平板回收检测的方法,探究其在水稻根茎叶中的定殖动态。结果显示：经GB519-GFP发酵液处理水稻种子、根和叶片后,菌株均可内生定殖于植株的表皮、皮层和维管束中,表明其可在水稻植株内迁移和定殖。GB519-GFP在处理部位的定殖量通常呈现先减少后增多的趋势,非处理部位3～5 d后即可检测到标记菌株。浸种处理,3 d后在幼芽中可检测到标记菌株;20 d后在根中的菌量最多,达5.7×105 cfu/g。灌根处理,1 d后根中菌量为5.4×105 cfu/g; 20 d后根、茎和叶中菌量均达到最大值;处理80 d后,根中定殖数量仍达1.9×105 cfu/g。叶面喷施处理,1 d后叶片菌量为4.2×105 cfu/g; 20 d后叶片菌量达4.4×105 cfu/g。不同处理方法在各部位的定殖量几乎均在处理20 d后达到峰值。...  相似文献   

17.
稻瘟病是水稻生产上的重要病害,了解稻瘟病菌群体毒性组成是水稻抗病品种合理布局的重要基础。2012-2015年从湖南桃江病圃中不含已知抗瘟基因的水稻品种‘丽江新团黑谷’上成功分离出351个稻瘟病菌单孢菌株,在温室于水稻5叶期采用离体接种法测定了其对24个水稻抗稻瘟病单基因系的毒性,结果表明,病圃中稻瘟病菌以广谱强致病性的菌株为主,病菌对不同抗瘟基因的毒力频率在50.56%~96.67%之间,而不同年度间对24个抗性基因均具毒性的菌株出现频率在0~15%之间。对2015年的每2个抗瘟基因的联合毒力分析表明,基因两两搭配后的联合抗病系数最高、联合致病系数最低的组合是Pi-3*Pi-k(RAC=0.19,PAC=0.43)。  相似文献   

18.
Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is a serious threat to rice production worldwide. In temperate regions, where rice is not cultivated for several months each year, little is known about the initial onset of the disease in the field. The main overwintering and primary inoculum sources reported are infested residues and seeds, but the subsequent steps of the disease cycle are largely unknown, even though a systemic infection has been proposed but not demonstrated. The present work follows rice blast progression in infected seeds from germination to seedling stage, with direct and detailed microscopic observations under both aerobic conditions and water seeding. With the use of GFP‐marked M. oryzae strains, it was shown that spores are produced from contaminated seeds, infect emerging seedling tissues (coleoptile and primary root) and produce mycelium that colonizes the newly formed primary leaf and secondary roots. Using different rice cultivars exhibiting distinct levels of resistance/susceptibility to M. oryzae at the 2/4‐leaf stage, it was observed that resistance or susceptibility of a considered genotype is already established at the seedling stage. The results also showed that when plants are inoculated either at ripening stage (mature panicles), heading stage (flowering/immature panicles) or even before heading (flag leaf fully developed), they produce infested seeds. These seeds produce contaminated seedlings that mostly die and serve as an inoculum source for healthy neighbouring plants, which gradually develop disease symptoms on leaves. The possible rice blast disease cycle was reconstructed on irrigated rice in temperate regions.  相似文献   

19.
禾谷丝核菌(Rhizoctonia cerealis)是引起我国小麦纹枯病的主要致病菌。为了建立高效稳定的禾谷丝核菌遗传转化体系,本试验比较研究了不同细胞壁降解酶、酶液浓度、酶处理温度和时间等因素对禾谷丝核菌原生质体制备的影响,利用正交设计试验优化了原生质体再生条件。结果表明,液体培养6d的菌丝,采用15mg/mL溶壁酶+10mg/mL蜗牛酶组成的混合酶液,30℃下酶解4h,可以获得较高的原生质体释放量,可达到3.0×106个/mL;禾谷丝核菌原生质体再生的最佳条件是以SuTC缓冲液作为渗透压稳定剂悬浮原生质体,采用单层混菌法接种于TB3再生培养基,原生质体再生率可达到58.6%。禾谷丝核菌原生质体制备和原生质体再生条件的优化,为深入研究禾谷丝核菌生长发育的分子遗传学基础和进一步探索小麦纹枯病的致病机理奠定了基础。  相似文献   

20.
由稻瘟菌侵染引起的稻瘟病是威胁水稻安全生产最严重的真菌病害之一。鉴定克隆水稻抗稻瘟病基因, 系统深入研究稻瘟菌与水稻的相互作用, 揭示水稻的抗病机制, 进而创制推广抗稻瘟病新材料, 对确保粮食安全具有重要意义。本文总结了近10年来稻瘟病抗病基因和感病基因的鉴定、分子机理解析和应用等进展, 总结归纳了抗病基因聚合、分子设计育种、感病基因编辑、抗病基因的病原诱导表达等抗病育种主要策略。最后提出充分利用种质资源, 利用新技术挖掘新基因及创制新材料, 深入研究叶瘟和穗瘟抗病机制差异等是稻瘟病抗病育种下一步重点研究方向和新挑战。  相似文献   

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