共查询到20条相似文献，搜索用时 15 毫秒
1.
ABSTRACT Developing resistant cultivars requires an understanding of the dynamics of the pathogen populations as well as the genetics of host resistance. Bacterial leaf blight (BB), caused by the vascular pathogen Xanthomonas oryzae pv. oryzae, has become one of the most devastating diseases of rice. We demonstrate here the quantitative analyses of responses of near-isogenic lines carrying various BB resistance (R) genes and R-gene combinations against 16 X. oryzae pv. oryzae isolates representing Korean BB pathotypes. The estimated main effects of each R gene against the 16 isolates identified prominent differences in BB pathotypes between Korea and other countries. Three major aspects of our quantitative observations and statistical analysis are (i) strong and broad resistance of xa5; (ii) independent and additive genetic actions of Xa4, xa5, and Xa21 under digenic or trigenic status; and (iii) a strong quantitative complementation effect contributed by the functional alleles of Xa4 and Xa21. We conclude that the pyramid line containing genes Xa4, xa5, and Xa21 would be the most promising and valuable genotype for improving Korean japonica cultivars for BB resistance. 相似文献
2.
New gene for bacterial blight resistance in rice located on chromosome 12 identified from minghui 63, an elite restorer line 总被引：1，自引：0，他引：1
ABSTRACT Bacterial blight, caused by Xanthomonas oryzae pv. oryzae, is a serious disease of rice worldwide. A new dominant gene for bacterial blight resistance in rice, Xa25(t), was identified from Minghui 63, a restorer line for a number of rice hybrids that are widely cultivated in China. This gene conferred resistance to Philippine race 9 (PXO339) of X. oryzae pv. oryzae in both seedling and adult stages. It was mapped to the centromeric region of chromosome 12, 2.5 cM from a disease resistance gene-homologous sequence, NBS109, and 7.3 cM from a restriction fragment length polymorphism marker, G1314. The genomic location of this gene is similar to the previously identified blast resistance genes, Pi-ta and Pi-ta2. 相似文献
3.
ABSTRACT Among the 171 strains of Xanthomonas oryzae pv. oryzae (the bacterial blight pathogen of rice) collected from eight rice-producing zones in Nepal, 31 molecular haplotypes were distinguished using two polymerase chain reaction-based assays. Six common haplotypes represented nearly 63% of the strains, and some haplotypes were geographically dispersed. Multiple correspondence analysis divided the collection into five putative genetic lineages. Lineages 1, 2, and 4 were the most frequently detected and occurred in diverse geographic populations. Twenty-six pathotypes (virulence phenotypes) of X. oryzae pv. oryzae were identified using 11 near-iso-genic rice lines, each containing a single gene for resistance. The 26 pathotypes grouped into five clusters, and cluster 1 contained wide virulence spectrum strains from all geographic populations. Although molecular variation was greatest between strains of different virulence phenotypes, some variation was observed among strains with identical virulence. There was a weak correlation (r = 0.52) between molecular haplotypes and virulence phenotypes. There are two major groups of X. oryzae pv. oryzae in Nepal. One group consists of strains with high molecular polymorphism and many pathotypes that are either virulent to the 11 major resistance genes or avirulent only to Xa21. Strains in the second group have low molecular polymorphism and are avirulent to Xa4, xa5, Xa7, and Xa21. 相似文献
4.
5.
The relationship between bacterial blight resistance gene Xa3 and browning reaction was genetically analyzed using F2 plants from the cross of rice cultivar Kuntulan with Kinmaze. Kuntulan harbors resistance Xa3 and developes a browning reaction to avirulent races of Xanthomonas oryzae pv. oryzae, whereas Kinmaze has a typical susceptible reaction to all known Japanese races of X. o. pv. oryzae. The F2 plants were tested for their resistance to avirulent race II strain of X. o. pv. oryzae and the development of browning. Of 337 F2 plants tested, 251 had resistance to the strain. In all the resistant plants, a browning reaction developed around the point
of inoculation. The remaining 86 had a susceptible reaction to the strain without a browning reaction. The F2 population of Kuntulan × Kinmaze had a clear-cut segregation ratio of 3R : 1S. These facts led to the conclusion that the
browning reaction is a pleiotropic effect of Xa3.
Received 29 January 2001/ Accepted in revised form 24 April 2001 相似文献
6.
Takashi OKU Kotaro SATO Masaki KURAO Shohei MATSUURA Yasufumi SAKAI Takao TSUCHIYA 《Journal of General Plant Pathology》2000,66(4):332-334
The pathogenic race of 59 cultures of Xanthomonas oryzae pv. oryzae, a pathogen of bacterial leaf blight of rice, isolated from six locations in the inland mountainous area of Hiroshima Prefecture
in 1999, were determined by a set of traditional differentials. Four races—I, II, V and VII—were found across the area; however,
we noticed the composition of the races as well as the dominant race in each location different. All races were avirulent
on differential cultivar Te-tep. Races V and VII were new to Hiroshima. The rice cultivars infected with bacterial leaf blight
in Hiroshima are thought to be grouped into the Kinmaze group, which does not have any resistance genes. Apparently, a variety
of races occurred unexpectedly on the cultivars contrary to stabilizing selection theory.
Received 25 February 2000/ Accepted in revised form 13 July 2000 相似文献
7.
安徽省水稻品种对水稻白叶枯病的抗性及白叶枯病小种鉴定 总被引：1，自引：0，他引：1
为明确安徽省白叶枯病菌小种组成及常用、备用品种对该病的抗性,用白叶枯病强毒性小种FuJ和YN24、中等致病力的安徽省优势小种AH以及弱致病小种YN7对安徽省常用及备用水稻品种进行人工接种鉴定;用鉴别品种IRBB5、IRBB13、IRBB3、IRBB14、IRBB2、R24对安徽的白叶枯病菌株进行鉴定.结果表明,有3.5％的品种抗FuJ,15.4％的品种抗YN24,29.8％的品种抗AH;安徽省白叶枯病菌小种有R2、R5和R8,其中R5为优势小种.抗AH的品种可以用于安徽的水稻生产;生产中应防止FuJ和YN24等毒性强的菌株传入. 相似文献
8.
Lesion development, bacterial multiplication and spread were measured in leaves of cultivars of rice containing different Xa (resistance) genes, following inoculation with different races of the bacterial leaf blight pathogen. Xanthomonas campestris pv. oryzae. Both compatible and incompatible races possessed the ability to colonize rice plants. The difference between compatible and incompatible host pathogen combinations appeared to be mainly in symptom production since multiplication rates and spread were very similar until after the onset of symptoms. No form of HR (hypersensitive response) was observed. The ability of incompatible races to modify host reaction in dual-inoculation was dependent on the genotype of the host plant. The heterologous non-pathogen of rice X. campestris pv. campestris produced few symptoms, failed either to multiply or spread within rice leaves and was unable to induce any marked cross-protection against homologous pv. oryzae strains in dual-inoculation experiments. 相似文献
9.
10.
The interactions between Xanthomonas oryzae pv. oryzae (Xoo) and rice are controlled in a gene-for-gene manner. In this study, a 359 bp DNA fragment of the avrXa3 gene containing three nuclear localization signal (NLS) motifs present in all members of the avrBs3/pthA family was used as a probe to screen a genomic library of the JXOIII strain of Xoo. The results demonstrated that diverse members of the family exist in the pathogen genome. The avrBs3/pthA genes occurred at isolated individual portions or in clusters. The positive avr gene clones were transferred into the virulent recipient PXO99A . Pathogenicity tests in near isogenic lines of rice confirmed that four resistance (R) genes ( Xa2 , Xa3 , xa5 and xa8 ) matched the four avr genes ( avrXa2 , avrXa3 , avrxa5 and avrxa8 ) in the genome of Xoo strain JXOIII. The avrBs3/PthA -like gene (1·7 kb) present in cosmid p54, may specifically interact with the Xa3 gene present in IRBB3, and is designated avr/pthA3 . Sequencing indicated that there are only 1·5 copies of the 102 bp repeat unit in avr/pthA3 . Alignment of the twelfth and thirteenth amino acids in the repetitive units encoded by this gene with those in other representatives of the AvrBs3 family revealed a unique repeat arrangement which might contribute to variation in the avirulence genes in Xoo. The parental rice line IR24 was found to contain several R genes for resistance to Xoo bacterial blight. 相似文献
11.
ABSTRACT The ability of some phytopathogenic bacterial strains to inhibit the growth of others in mixed infections has been well documented. Here we report that such antagonistic interactions occur between several wild-type strains of the rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae. In mixed inoculations, a wild-type Philippine strain was found to inhibit the growth of a wild-type Korean strain. Furthermore, a nonpathogenic mutant of the Philippine strain maintained these antagonistic properties. Growth curve analysis indicated that both the wild-type Philippine strain and its nonpathogenic mutant inhibited the growth of the Korean strain 2 days after infection and prior to the onset of disease symptoms. When mixed with the nonpathogenic mutant, 10 out of 18 diverse wild-type X. oryzae pv. oryzae strains did not cause disease. Conversely, three of the strains that were not affected by the nonpathogenic mutant were found to inhibit the growth of both the wild-type and mutant Philippine strains, indicating that antagonism is widespread and strain specific. The observed growth inhibition occurred only in planta and did not correlate with bacteriocin activity in vitro. Antagonistic interactions also were found to affect resistance (R) gene-mediated resistance. The R gene Xa21 was capable of protecting rice plants coinoculated with nonantagonistic virulent and avirulent strains; however, when avirulent strains were coinoculated with virulent antagonistic strains, disease ensued. Taken together, these results indicate that X. oryzae pv. oryzae has evolved strategies to compete with rival strains in a fashion that allows virulent strains to evade R gene-mediated protection even when avirulent strains are present in the inoculum. 相似文献
12.
为研究山栏稻对白叶枯病抗性,本试验以17个山栏稻品种为材料,在大田与温室大棚中同时种植,于大田中观察山栏稻在水、旱两种栽培模式下对海口当地白叶枯病菌的自然抗性并测产;在温室中检测水、旱两种栽培模式下山栏稻对菲律宾白叶枯病菌小种PXO99(P6)、PX145(P7)的抗性;并以基因功能性标记检测其抗性基因,分析各指标与抗病性的关系。结果表明,大田环境下17个供试品种中有12个品种在水作栽培模式下感病指数高于旱作,有10个品种水作栽培模式下产量比旱作高。温室中用P6接种山栏稻,水作模式下仅有1个品种表现抗病,8个品种感病;旱作模式下2个品种表现抗病,3个品种感病。接种P7,水作时表现抗病和感病的品种数量分别为7个和2个;旱作时表现抗病的品种高达9个,仅1个品种感病。供试品种中有16个品种含有Xa1抗病基因,4个品种含有Xa27抗病基因,所有品种均不含xa13、Xa21抗病基因。因此认为,山栏稻对海口当地白叶枯病菌小种以及菲律宾白叶枯病菌小种都有一定抗性,且抗性受栽培条件的影响,山栏稻旱作时抗性强于水作。 相似文献
13.
ABSTRACT Sixty strains of Xanthomonas oryzae pv. oryzae, collected from 29 locations in Sri Lanka in 1995, were analyzed by restriction fragment length polymorphism using either polymerase chain reaction-amplified 16S and 23S rDNA or the repetitive DNA element IS1112 from X. oryzae pv. oryzae as hybridization probes. Two different ribogroups were observed in the Sri Lankan strains using rDNA probes, whereas five clusters were identified by the IS1112 probe. Bootstrap analysis revealed that the five clusters defined by IS1112 were relatively robust. Our results suggest that the Sri Lankan strains are phylogenetically composed of five different groups. Each cluster was partially associated with climatic conditions (intermediate zone and wet zone) and was related to groups based on ribotyping. Based on virulence analysis using 12 rice cultivars, each containing a single resistance gene, 14 pathotypes were identified among the Sri Lankan strains. All strains were virulent to resistance genes Xa1, Xa2, Xa4, Xa10, Xa11, and Xa14. Only one strain (pathotype 1) was virulent to all major resistance genes including Xa21, while strains of the other pathotypes were all avirulent to Xa21. A partial relationship was found between the determined phylogenetic groups using the IS1112 probe and pathotypes for all but two clusters. The results of this study will facilitate the further understanding of the population structure of X. oryzae pv. oryzae in Sri Lanka. 相似文献
14.
为选育水稻抗性品种和发掘抗白叶枯病基因,以来自中国、日本和菲律宾的9株革兰氏阴性菌黄单胞菌水稻变种Xanthomonas oryzae pv. oryzae菌株为供试菌株评价137份云南省地方稻种质资源对白叶枯病菌的抗性,同时检测供试材料中含14个已克隆抗白叶枯病基因的情况。结果显示,供试材料中至少对1株黄单胞菌水稻变种菌株有抗性的材料有104份,抗1、2、3、4、5、6、7、8和9株黄单胞菌水稻变种菌株的材料分别有25、19、14、19、11、6、5、2和3份;其中白杂一号、珍白18、麻旱谷、老来红、晋糯、香谷、毫冷薅、齐头蚂蚱谷、九谷和来之不易10份材料抗谱较广。大部分抗性材料携带1～7个白叶枯病抗性基因或其同源基因,未检测到含有Xa7、xa13、Xa21和Xa45(t)基因或其同源基因的材料。供试材料携带的抗性基因数量与抗性水平均呈极显著相关。 相似文献
15.
水稻品种(组合)抗白叶枯病基因初探 总被引：1，自引：0，他引：1
用菲律宾6个白叶枯病菌系(小种),将95个水稻品种(品系)划分为5个品种类群,为今后开展品种抗病性的基因分析提供了必要的条件。通过测试,提出舟松62、二九丰(早籼) 城特232、T8528、H101、6003、T88506、T88517、R895、绍糯8843、丙88151、台202、T88522(晚粳)等13个具有广谱抗性的品种(系),可作杂交亲本利用。 相似文献
16.
Genetic relationship between races of Pseudomonas syringae pv.pisi and cultivars of Pisum sativum 总被引：1，自引：1，他引：0
Isolates of Pseudomonas syringae pv. pisi from the UK and overseas were categorized into six races on the basis of their reactions to a range of differential pea (Pisum sativum) cultivars. Race 2 was predominant among the isolates examined and this probably reflects its relative international importance. A previously uncharacterized race (race 6) was virulent on all cultivars tested. Resistance to races 1-5 was widespread in commercial cultivars and breeding lines with more than 75% showing resistance to one or more races. A preliminary study of the inheritance of resistance indicated that for races 1, 2 and 3, resistance was controlled by different dominant genes. The genetic basis for the relationship between races of P. syringae pv. pisi and pea cultivars was explained in terms of a gene-for-gene relationship involving five matching gene pairs. With further clarification of the genetics of resistance this host-pathogen association will meet most of the requirements of a model system for the study of the genetic and molecular basis of pathogenicity and host specificity. 相似文献
17.
Kimberly M. Webb Epifania Garcia Casiana M. Vera Cruz Jan E. Leach 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):399-407
Disease resistance genes most commonly used in breeding programs are single, dominant genes with relative effectiveness that
is sometimes influenced by plant developmental stage. Knowing the developmental stages at which a resistance gene is functional
is important for disease management. In rice, resistance at the seedling stage is crucial, because wounding during transplanting
increases the potential for bacterial blight disease, and not all bacterial blight resistance genes are effective at the seedling
stage. Effectiveness of the bacterial blight resistance genes Xa4, xa5, and Xa7, all in a common genetic background, was evaluated at different developmental stages by measuring lesion length and bacterial
numbers after inoculation with the bacterial pathogen, Xanthomonas oryzae pv. oryzae. The Xa4 and xa5 genes controlled disease at all growth stages. In contrast, Xa7 was not fully functional in very young seedlings, but was completely effective by 21 days after sowing (das). The effects
of plant developmental stage on interactions of the Xa7 gene with X. oryzae pv. oryzae strains carrying different mutant avrXa7 alleles were also tested. If a partial or fully functional avrXa7 allele was present, Xa7 resistance was effective at all growth stages tested after the transplant stage (>21 das). 相似文献
18.
Localizing the Bacterial Blight Resistance Gene, Xa22(t), to a 100-Kilobase Bacterial Artificial Chromosome 总被引：2，自引：0，他引：2
ABSTRACT The rice bacterial blight resistance gene, Xa22(t), provides resistance to a broad spectrum of Xanthomonas oryzae pv. oryzae isolates. Here, we localize the gene to a small 100-kb fragment of chromosome 11 by a combination of genetic recombination analysis and physical mapping. Mapping was done with two F(2) populations from the cross between Zhachanglong and Zhenzhuai. The first population consisted of 248 random individuals and 404 highly susceptible individuals selected from an F(2) population of more than 2,000 individuals and was used to construct a linkage map around the Xa22(t) locus. For the second F(2) population, 7,680 plants were examined with simple sequence repeat markers flanking the Xa22(t) locus to identify recombinants useful for fine-genetic mapping. Two large-insert bacterial artificial chromasome (BAC) libraries (from cvs. Teqing and Minghui63) were screened with a marker (R1506) which cosegregated perfectly with Xa22(t) in the first population. Restriction mapping of the resulting BAC clones enabled a physical map of the area to be constructed, and subclones from the BAC clones provided additional restriction fragment length polymorphism probes which could be placed on the fine-structure genetic map using the recombinants from the second mapping population. The Xa22(t) locus was mapped to a approximately 100-kb interval delimited by the R1506 marker and a subclone from the M3H8 BAC clone. 相似文献
19.
20.
Maria R. Finckh Rebecca J. Nelson 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(8):743-751
Eight Philippine races of Xanthomonas oryzae pv. oryzae have been identified based on virulence phenotypes observed on a set of five differential varieties. One of these, Race 3, was found to consist of two phylogenetically distinct lineages based on DNA fingerprinting analysis. To determine, if the two lineages could be differentiated based on host-specificity, 186 strains of Race 3 were analyzed with additional fingerprints and 76 selected isolates with additional differential rice varieties. The strains were separated into 36 haplotypes clustering in three groups (IS1113-B, -C, and -G) at the 75% similarity level. Isolates varied in their reaction to a rice line carrying the resistance gene Xa7, however, the variability was not consistent within lineage. Aggressiveness of isolates belonging to lineage IS1113-B and -G was significantly greater when tested during the dry season than when tested during the wet season. However, no such differences were evident for isolates from lineage IS1113-C, indicating that environmental effects presumably light and temperature are genotype-specific. 相似文献