Neck blast, caused by Pyricularia oryzae, seriously affect the yield and quality of rice. Previous results showed that a new species of Pyricularia, which was found by continuous monitoring in the rice fields in Jiangsu province, can cause neck blast-like with a high incidence and stable existence in different years. In order to understand the difference between the new pathogen and P. oryzae Guy11. The growth, sporulation, various stresses and resistance of different varieties to these two diseases were compared between the representative strain P. sp. jiangsuensis 18-2 and P. oryzae Guy11. The results showed that the growth of P. sp. jiangsuensis 18-2 on PDA, CM and SDC medium was significantly faster than that of P. oryzae Guy11, but the aerial mycelium of P. sp. jiangsuensis 18-2 was sparse. Under cell wall stress factor and oxidative stress, the tolerance of P. sp. jiangsuensis 18-2 to exogenous stress was significantly enhanced than that of P. oryzae Guy11, indicating that P. sp. jiangsuensis 18-2 was more adaptable to external stress response. Further analysis of the resistance of the main cultivars in Jiangsu province to panicle neck blast showed that some main cultivars had different resistance to panicle neck blast caused by P. sp. jiangsuensis 18-2 and P. oryzae Guy11. Varieties Zhendao 448, Yanjing 15, Jingliangyou 534 and Yongyou 2640 showed good resistance. In production, it is necessary to select the varieties with better resistance to these two diseases.

Litchi anthracnose caused by Colletotrichum gloeosporioides is an important disease in litchi production, which occurs on leaves, flower clusters, fruits, and postharvest fruits. In this study, the investigation was performed on inoculation method, leaf development stage, infection position, incubation time, and measure pattern of disease spot to evaluate the resistance and select resistant litchi genotypes by using a detached leaf inoculation method indoor. The results showed that the optimal condition to evaluate the resistance was stab inocu-lation of a mycelial agar disk (5mm) on the back of fresh leaves which had just reached the maximum leaf area, and observing the incidence and measuring the disease spot area at 72 h after inoculation. Fifty-five germplasm litchi materials were analyzed by this method and their resistance level was divided into 5 grades: immune, highly resistant, moderately resistant, moderately susceptible and high susceptible by using the square Euclidean separation matrix analysis method. This evaluation method and grade division standard for litchi resistance to C. gloeosporioides provide the theoretical basis for litchi resistance breeding and gene selection.

Xinjiang is the most important cotton production base in China, the output accounted for 85% of the country. Verticillium wilt is caused by Verticillium dahliae, which seriously hindered the development of cotton industry in Xinjiang. Therefore, 140 isolates collected and separated from cotton region of Xinjiang were stu-died, the results showed that the growth rate and spore production of isolates in different regions were significantly different, and the isolates were predominanted by the sclerotium type and defoliating type. Meanwhile, a new method for rapid identification of cotton seedling resistance to Verticillium wilt was established - seedling block quantitative inoculation method, and the pathogenicity of some isolates was detected on Zhongzhimian 2 and Xinluzao 36, respectively. The results showed that the isolates from cotton region of Xinjiang were dominated by strong and moderate pathogenicity type. In addition, the growth rate, spore production and pathogenicity of the defoliating type isolates were significantly higher than that of the nondefoliating type. All the results showed that the composition and differentiation of V. dahliae in cotton fields of Xinjiang had strong regional characteristics, this is of great significance to the rational distribution of cotton varieties and screening for the disease-resistant varieties.

Based on the artificial inoculation tests and the investigations in natural conditions for many years, it is found that the most rice varieties used in China were susceptible to rice false smut pathogen, Villosiclava virens. However, the disease severity in different rice varieties is quite different in paddy fields in natural conditions. Based on the number of rice false smut balls in a panicle, rice varieties can be divided artificially into the high susceptible with multiple smut balls and the relatively resistant varieties with few smut balls. To evaluate the relationship between the features in rice panicles at rice booting stage and the disease resistance, the panicle features in various rice varieties were measured and compared here. The results showed that there were significant differences in panicle size, floret density, panicle sheath closure and sealing, flag leaf area between high susceptible varieties with multiple balls and those with relatively resistant phenotype with few balls.The closure of panicle sheath in the resistant varieties was better than that in the susceptible ones.

To identify pathotypes different of Xanthomonas oryzae pv. oryzicola and rice varieties resistant to bacterial leaf streak from Yunnan Province. The virulence levles differentiation of 86 isolates of Xoc collected from 8 rice-growing areas in Yunnan province were identified, by using 6 rice varieties ( IRBB4, IRBB5, IRBB14, IRBB18, IRBB21, IR24) which each containing a single resistance gene. The cluster analysis using UPGMA method to Xoc virulence levels showed that 86 strains were classified as 9 pathotypes I-Ⅸ, Among the 9 pathotypes, the pathotype I is the dominant group and most of the pathotype I strains are SSSSSS disease phenotype. The pathotypes Ⅰ was dominant Xoc pathotype in various rice areas of Yunnan. Further research, resistance evaluation of 80 rice varieties from Yunnan Province to pathotype I strain NO.19, pathotype II strain NO.14 and pathotype VI strain NO.16,only 30.0%, 35.0% and 57.5% exhibited resistance to 3 pathotype strain respectively. 9 rice varieties showed resistance to three pathotype strains, especially Deyou16 and Changgui2 showed high resistance levels, this result will be one of the perfect ways to develop bacterial leaf streak disease resistance breeding.

Sensitivity of Bipolaris maydis to propiconazole, genetic diversity and pathogenicity of different propiconazole-sensitive populations of B. maydis in Fujian Province were studied using methods of measuring the mycelial growth on the fungicide-amended media, inter-simple sequence repeat (ISSR) molecular markers and conidial suspension inoculation, respectively. Sensitivity test results indicated that propiconazole-resistance has been developed among isolates of B. maydis in Fujian Province, and resistance factors among resistant isolates ranged from 2.1 to 9.4. A total of 153 loci were detected in 55 isolates of B. maydis using 10 screened ISSR pri-mers, and as high as 93.46% of these loci were polymorphic loci. The percentages of polymorphic loci in the population of propiconazole-sensitive, -intermediary and -resistant were 77.12%, 69.93% and 81.70%, respectively. The values of observed number of alleles, effective number of alleles, Nei’s gene diversity, and Shannon’s information index for the resistant population were higher than those for the sensitive population, suggesting that genetic diversity in the resistant population of B. maydis was more diverse than that of sensitive population. Clustering analysis indicated that genetic diversity of different propiconazole-sensitive populations had highly correlations with the level of fungicide resistance and geographical origin. Pathogenicity assays revealed that the different propiconazole-sensitive populations of B. maydis had highly virulent to 11 sweet corn cultivars. Nevertheless, the frequencies of high pathogenic isolates in the propiconazole-sensitive population on 9 corn cultivars were considerably less than those in the resistant population. These results provide a theoretical basis for the further study of genetic structure and the fungicide resistance monitoring of B. maydis.

Barley spot blotch, initiated by the fungal pathogen , happened frequently in most barley-grown areas in the world, and caused serious barley yield losses and also decreased grain quality. Development and wider application of resistant barley cultivars was the most effective control strategy for spot blotch. However, few barley resistance genes or genotypes to spot blotch were available in breeding programs. In this study, 233 representive barley germplasm accessions originating from China were screened for spot blotch resistance by artificial inoculation in adult-plant stage. Only 10 accessions among them such as Kenpimai 5 showed high resistance to all three isolates used, accounting for 4.3%. Another 37 spot blotch resistance barley lines from domestic and foreign were also evaluated for resistance levels to B.sorokiniana isolates in adult-plant and seedling stages respectively. The results showed that 41%-46% of the 37 accessions were resistant to spot blotch in adult-plant stage, but in seedling stage the resistance percentage ranged from 50% to 64%.Eleven barley lines such as ND 17293 were resistant to all three isolates used both in adult-plant and seedling stages. These resistance lines can be still utilized as resistance sources. Based on the spot blotch resistance identification results with 3 isolates, resistance percentage of the barley accessions in seedling stage was usually higher than in adult-plant stage, indicating that there is great difference between barley seeding and adult-plant resistance to spot blotch. In addition, barley accessions showed resistance specificity to pathotypes of B. sorokiniana.

Leymus racemosus is a wild relative of wheat and has high resistance to wheat Fusarium head blight (FHB). The transfer of FHB resistance gene from L. racemosus to Triticum aestivum is of great significance for broadening the resistance of wheat germplasm. To obtain T. aestivum-L. racemosus translocation line with FHB resistance, the pollen of T. aestivum-L. racemosus disomic addition line DA5Lr was irradiated by ⁶⁰Co-γ-rays 1200 R (100R·min^-1) and then pollinated to emasculated T. aestivum cv. Chinese Spring. One plant with one T. aestivum-L. racemosus translocation chromosome was detected from the M₁ plants by genomic in situ hybridization (GISH). This plant was self-pollinated, and the progenies with two translocation chromosomes were analyzed for chromosome pairing behavior at meiotic metaphase I of their pollen mother cells (PMCs). One ring bivalent was observed at meiotic metaphase I in one of the progenies, indicated that the plant was translocation homozygote. Using Oligo-pAs1-2 and Oligo-pSc119.2-2 as probe, the translocation line was further identified as T5AS/5LrL translocation line by C-banding and sequential GISH-FISH analysis. Three EST-STS markers, BE591127, BQ168298 and BE591737, were selected and could be used for tracing the translocation chromosome. Three years’ FHB resistance tests of T5AS/5LrL showed that the proportions of scabbed spikelets were 7.69%, 10.29% and 8.66%, respectively, which was obviously lower than that of susceptible varieties Chinese Spring and Mianyang 85-45 .The translocation line will provide a new source for FHB resistance in wheat breeding

Heat shock proteins are widely present in various organisms and respond to a variety of biotic and abiotic stresses. Previous studies showed that over-expression of the small heat shock protein gene OsHsp18.0-CI can increase the resistance to bacterial leaf streak by enhancing rice basic defense response. This study found that the OsHsp18.0-CI gene can also be induced by PXO99, a strain of Xanthomonas oryzae pv. oryzae (Xoo) which caused bacterial blight in rice. Over-expression of OsHsp18.0-CI could enhance resistance to several Xoo strains in rice. Transcriptome sequencing analysis showed that OsHsp18.0-CI gene-mediated resistance to bacterial blight is not only partly similar to its resistance pathway to bacterial leaf streak, but also a large number of new unknown function genes are involved. The above results indicate that the OsHsp18.0-CI gene can increase resistance to bacterial blight by enhancing the basic defense response of rice infected with pathogenic bacteria of Xoo.

Phenotypic characteristics of resistance to rice blast, sheath blight, bacterial blight, and bacterial leaf streak of seven different populations of Oryza offcinalis from Yunnan Province were identified. Detection of the presence of cloned resistant genes of rice blast and bacterial blight was carried out. The results showed that six O. offcinalis populations except Menghai (7) had resistance to rice blast. The Mengzhe (4) and Jingnashanggou (1) did not contain Pib and Pi2, respectively, and all of other five O. offcinalis populations contained Pib, Pi2, Pi9, Pid2, Pikp, Pis, and Pi56. All tested O. offcinalis populations showed high resistance to sheath blight and bacterial leaf streak isolates RS105 and RS1-20, except Mengzhe (5) was susceptible to isolate RS1-20, Mengwang (13) and Lancangmengkuang (14) was susceptible to isolate RS105. Strong virulent isolate of Yunnan Xoo CX30-1 and Philippines Xoo isolates PXO99 and PXO86 had strong pathogenicity to Jingnashanggou (1) and Lancangmengkuang (14), but other wild rice populations showed resistance or moderate resistance to these three isolates. Seven O. offcinalis populations contained Xa5, Xa13, and Xa21 genes. This study is the first report that O. offcinalis populations of Yunnan had different characteristics of resistance to four diseases, which will be beneficial to laying foundation for deeply digging resistance genes from O. offcinalis in Yunnan Province.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide, especially in China. Wheat relatives are important donors of resistance genes against this disease in wheat breeding program. M852-1, a wheat-Elymus mollis translocation line, is highly resistant to seven main Pst races or new pathotype of China (CYR29, CYR31, CYR32, CYR33, Su11-4, Su11-7 and V26), and is a preferable stripe rust resistant material. F₁, F₂, F₃ and BC₁generations derived from cross M852-1/ Mingxian169 were tested with prevalent Pst race CYR33. The genetic analysis results indicated that the resistance of M852-1 to CYR33 was controlled by a single recessive gene, tentatively designated as YrElm. The resistance gene was mapped using a F₂ population from M852-1/Mingxian169 and bulked segregant analysis (BSA). YrElm was linked with five simple sequence repeat (SSR) markers, Xcfd35, Xgwm161, Xwmc630, Xgwm533 and Xcfd34, which were located on wheat chromosome 3DS. The genetic distances of the closest flanking markers, Xcfd35 and Xgwm161, were 6.5 cM and 4.2 cM, respectively. Pedigree analysis, chromosomal location and molecular test suggested that YrElm might be a novel stripe rust resistance gene which was derived from Elymus mollis. Two closest flanking SSR markers, Xcfd35 and Xgwm161, were used to test 68 wheat cultivars from Gansu and Huanghuai wheat region. The results showed that ten (14.7%) cultivars had the same polymorphic bands as M852-1. However, resistance identification and pedigree analysis suggested that these ten cultivars might not carry the stripe rust resistance gene YrElm. The polymorphic SSR markers identified in this research can be useful in wheat molecular marker select breeding and fine mapping.

In order to confirm the Fusarium head blight (FHB) Type II resistance of different wheat cultivars (lines) and the concentration of deoxynivalenol in various tissues of wheat lines in China was evaluated for FHB resistance and concentrations of DON in kernels, chaff and rachis were tested. The plants were inoculated with mixed isolates of Fusarium graminearum in the field by injecting conidia into a single spikelet of each spike. FHB symptoms were evaluated by visual inspection in the field, and concentration of DON was analyzed by ELISA. The results showed that significant differences in FHB ratings and the concentrations of DON in kernels, chaff and rachis were observed among cultivars. There was no resistant and moderately resistant wheat culitivals (lines), 14 of evaluated cultivars (lines) (13.2%, including Huayu 198, Zhengmai 103, Chunfeng 0021, and so on) were moderately susceptible; 92 of evaluated cultivars (lines) (86.8%, including Zhaoshi 2010-06, Bainong 898, Zhongmai 63, and so on) were susceptible. The DON levels in kernels of evaluated cultivars ranged from (0.70－287.63)mg/kg, and that of 3 cultivars, including Zheng 03876, Yubao 1 and Zhongmai 63 were below 2 mg/kg, which may be useful as sources for breeding wheat cultivars. The DON levels in chaff and rachis ranged from (51.03－392.87)mg/kg, were much higher than that in kernels. Correlation coefficients were significant between FHB symptom ratings and DON levels in kernels.

Screening rice germplasm resources with resistance to sheath blight (SB) disease, caused by Rhizoctonia solani, is the prerequisite for rice breeding against this disease. In the present study, the seedling resistance of 299 rice accessions from five different sub-populations and one mixed population to SB disease was evaluated by artificial inoculation in green house. Five varieties with known SB resistance levels were included as controls to determine the resistant levels of new germplasms. The resistances of the five controls could be effectively distinguished to different resistant levels by using the “mist-chamber” method with the improved inoculum and the “0-9” rating scores that were calculated based on the height of the tallest leaf sheath. No rice variety was found to be immune and high resistant to R. solani, and only 36.5% of the tested varieties showed resistant and moderate resistant to SB disease. For different rice sub-populations, the AUS population had the highest ratio (more than 60%) of varieties with resistant and moderate resistant levels, then followed by ARO population with 54.6%; the TRJ population had the lowest ratio (only 22.7%) of resistant varieties. Based on the difference between YSBR1, a widely used SB-resistant control variety, and the tested varieties on the seedling height and SB scores, seven varieties among the 299 accessions were believed reaching resistant level to SB, and the variety Bico Branco showed significantly stronger resistance to SB than that of YSBR1. Results of the study will not only provide the new resistant germplasms for rice breeding against SB disease, but also guide breeders to select appropriate sub-population in breeding program for developing SB-resistant rice varieties.

To establish a virulence evaluation method under hydroponic system for Fusarium oxysporum f.sp. cubense based on the improved banana hydroponic culture system, factors affecting pathogenicity of F. oxysporum f.sp. cubense including inoculum concentration, suspension type and treatment method were analyzed, and the results were also compared with those by inoculation of potted plants to verify the accuracy of the hydroponic test. It was indicated that: In banana hydroponic culture system, 50 mL of spore suspension shaking-cultured for 5 days with a diluted concentration at 1×10⁶ cfu·mL^-1 could be used for virulence evaluation, and the results were basically the same as those obtained by potted seedlings measurement. This study provides a quick and easy way for virulence evaluation of the corresponding different isolates and may be helpful for pathogenesis research on F. oxysporum and breeding for disease resistance in the future.

Dry mycelium of Penicillium chrysogenum(DMP),a waste product of the pharmaceutical industry,was shown to enhance pathogen-resistance in many crops. The effects of DMP on defense responses in tobacco BY-2 cell suspensions and the mechanism of DMP-induced resistance were studied. The defense responses elicited by DMP in tobacco BY-2 cells included an oxidative burst, extracellular alkalinisation, changes of phenylalanine ammonia lyase (PAL) and peroxidase(POD)activities, and expression of three defense-related genes PR-1a, PR-1b and NPR1. The amount of H₂O₂ reached the highest level at 30 min after DMP-treatment. Alkalinisation response was induced by DMP in the cell suspensions, but reduced partially by protein kinase inhibitor K252a. The enzyme activities of PAL and POD increased quickly after DMP-treatment, and reached the highest level at 4 h and 8 h, respectively. Our data suggest that DMP could induce a series of defense responses in tobacco BY-2 cell suspensions, in which SA-dependent signal pathway and protein phosphorylation events may be involved.

A broad survey was conducted and infected heads of wheat were collected from 33 counties in Si-chuan, Chongqin, Hubei, Anhui, Jiangsu and Henan Provinces in 2008. Totally 433 Fusarium single spore isolates were obtained and the population and mycotoxin chemotypes had been studied through PCR assay.Four Fusarium species, F. asiaticum, F. graminearum, F. avenaceum and F. meridionale,were detected in Sichuan , while two species F. asiaticum and F. graminearum were detected in Chongqing, Hubei, Anhui and Jiangsu. In Henan Province, only F. graminearum was found. Chemotype detection results showed that Nivalenol was the main chemotype in Sichuan and Chongqing, while Deoxynivalenol was the major chemotype in Hubei, Henan, Anhui and Jiangsu. After further divided the DON chemotype strains into 3-AcDON and 15-AcDON, the results showed that 3-AcDON isolates mainly lied in Sichuan, Hubei and Jiangsu, both 3-Ac-DON and 15-AcDON isolates mixed in Anhui, and all the isolates in Henan belonged to 15-AcDON. The results indicated that F. asiaticum was the dominant specie in Sichan, Chongqing, Hubei and Jiangsu Prov-ince. It also showed that there was a clear geographical distribution of DON and NIV produced by Fusarium species. NIV was the dominant chemotype in wheat producing region belonged to the upper reaches of Yangtze River while DON was the dominant chemotype in the lower reaches. There were some relationship between DON chemotype and Fusarium species.

Guinong22, a common wheat cultivar originated from the derivative of Haynaldia villosa and Triti-cum durum, is highly resistant to all the known Chinese races and pathotypes of Puccinia striformis f. sp. triti-ci(Pst). To study genetics and develop molecular markers for stripe rust resistance gene(s), F2 , BC1 F1 and BC1 F2 progenies derived from crosses Guinong 22 / Huixianhong or Ginong 22 / Mingxian 169 were inoculated with Chinese Pst races CYR29, CYR30, CYR32, CYR33 and Su11-11 at the seedling stage under controlled greenhouse conditions. One of BC1 F2 generation was selected to screen the polymorphic marker linked to the gene conferring resistance to Su11-11. The results indicated that Guinong 22 had at least three stripe rust resis-tance genes. Two polymorphic SSR markers, Xwmc44 and Xcfa2147 were linked to the recessive gene confer-ring resistance to Su11-11 with genetic distance 5. 1 and 7. 3 cM, repectively. Based on SSR loci, the gene was located on wheat chromosome 1BL and temporarily designated as YrGn22. Gene origination, resistance and molelcular tests suggested that YrGn22 was different from the known stripe rust resistance genes Yr3, Yr9,Yr21 and Yr29 located on chromosome 1BL, and might be a new gene.

Verticillium dahliae Kleb. harms seriously production of cotton. Thirty-one cotton cultivars with different resistance were used in the greenhouse, aimed to analyse the resistance to Verticilium wilt in cotton.Tissue structure was studied to realize the resistance mechanism of cotton to Verticilium wilt using the method of root scanning and paraffin slice. The results showed that:the density of roots which absorbed water and nu-trition had correlation with the disease index, r = 0. 923. There was significant difference in total root length,total projective area, total surface area and absorbable root length density among the resistance, tolerance and susceptible cultivars. But the difference between those of the tolerance and susceptible cultivars were not sig-nificant. The density of xylem parenchyma cells and vessel numbers in root and stem of resistant cultivars were the biggest, that of tolerant cultivars were the next and that of susceptible ones were the least, but the diameter of vessels were contrary. The absorbable root length density, density of xylem parenchyma cells and vessel numbers in root and stem can be used as measuring index of resistance to verticillium wilt in cotton.

A total of 286 recombinant inbred lines (RILs) and their parents, CO39 and Xiangzi 3150, were inoculated with Magnaporthe oryzae by natural inoculation for evaluation of rice field leaf-blast resistance in the blast nursery at Taojiang county. The results showed that 14 QTLs were detected in the regions exceeding 2. 5 LOD. These QTLs were mapped on chromosome 3, 8 and 10 respectively; accounting for 11. 78% -40.57% of the phenotypic variance. QTLs responsible for different field resistance traits were tightly linked each other, or the individual putative QTL contributed simultaneously to different field resistance traits vari-ation.

Evaluation for resistance of 251 rice varieties (lines) to rice blast disease was accomplished by using 22 differential isolates of Magnaporthe oryzae. Clustering analysis and genotype postulation were completed by unweighted pair group method with arithmetic mean. Resistance test data showed that significant diversity of resistance spectra to differential isolates was found among the total of 251 rice varieties (lines).These varieties (lines) were classified into 12 groups according to the reaction patterns of resistance or susceptibility to differential isolates. The tested varieties (lines) of different groups displayed distinct variation for reaction patterns and resistance frequncy. Genotype postulation indicated that 14 Pi-genes were involved in 70 of 251 varieties (lines).Another 181 varieties harbored none of the tested Pi-genes, however, they all carried other Pi-genes. The results from clustering analysis were not simply corresponding to those from genotype postulation. Ten varieties (lines), such as Zhenke, were able to be candidate materials for field resistance evalution.

This study was carried out to determine the induction of jasmonic acid (JA) on powdery mildew resistance in wheat, the activation of the expression of plant disease resistant marker genes （PR-1, PR-2 and PR-5）as well as a new cloned gene Ta-JA2, and to investigate the relationship between the induced resistance and the gene expression patterns. Susceptible cultivars “Chinese Spring”, “Pumai 9” and “Zhoumai18” were used to study wheat resistance activated by methyl jasmonate (MeJA) and powdery mildew resistance was then assessed with detached leaf assay. Real time quantitative RT-PCR was used to determine the expression patterns of PR-1, PR-2, PR-5 and Ta-JA2. The results demonstrated that MeJA application enhanced the powdery mildew resistance of “Chinese Spring”, “Pumai 9” and “Zhoumai 18”. The induced resistance could be detected from 12 h to 96 h after MeJA treatment, and the top value was at 24 h. MeJA significantly activated the expression of PR-1, PR-2, PR-5 and Ta-JA2. The induced powdery mildew resistance was positively associated with the induced expression of PR-1, PR-2, PR-5 and Ta-JA2. The phytohormone MeJA is a signal molecule in wheat powdery mildew resistance reaction.

Magnaporthe oryzae(M.oryzae),a hemibiotrophic pathogenic fungus,can infect rice(Oryza sativa) and cause rice blast.The mechanisms involved in resistance of rice to blast have been studied extensively.However,it is difficult to investigate interactions between rice and M.oryzae because of the relatively large genome sequence of rice and the diversity of M.oryzae.The strain of M.oryzae,Y34,was found to be able to infect Arabidopsis thaliana Col-0 plants,so M.Oryzae(Y34)—Arabidopsis thaliana pathosystem was established to investigate the role of Arabidopsis thaliana ENHANCED DISEASE RESISTANCE 1(AtEDR1),which exerts negative regulation on powder mildew resistance by salicylic acid(SA) pathway.The results indicated that edr1 mutant was more susceptible to M.oryzae than wild type Col-0 plants.Previous double mutant analysis revealed that all edr1-associated disease resistance phenotypes were suppressed by mutants that block SA perception(nim1) or reduced SA production(pad4 and sid2).These double mutants were inoculated with Y34 to examine if they would suppress the susceptibility of edr1 to M.oryzae,and the results showed that compared with edr1,all double mutants exhibited resistance to M.oryzae.These data suggest AtEDR1 may play a positive role in the regulation of resistance to M.oryzae in Arabidopsis,which is required for SA pathway.

A total of 178 Magnaporthe oryzae (M. oryzae) isolates, collected from different rice-cropping districts of Heilongjiang Province in 2006, were tested for pathogenicity against 12 Japanese and 7 Chinese differential varieties (DVs), 24 rice monogenic lines (MLs) with different blast resistance genes and 6 local leading cultivars. The results showed that 104 Japanese races (pathotypes) were identified and the predominant ones were 077.7, 017.1, 017.5 and 037.5. Resistance gene Pi9(t) expressed the broadest resistance spectrum (on average 97.75%) to all the blast isolates tested, and was of the highest utilization value in rice resistance breeding. Resistant genes Piz-5 and Pi12(t) also showed high utilization values due to their resis-tance spectra were 78.09% and 78.65%. The results showed that some resistance gene could upgrade the blast resistance of rice varieties, for example, Pi9(t) and Piz-5 upgrade the blast resistance of Kong Yu 131; Pi5(t) and Pita-2 upgrade the blast resistance of Ken Dao 10; Pi9(t) and Pita upgrade the blast resistance of Shang Yu 397; Piz-5 and Pi12(t) upgrade the blast resistance of Ken Dao 12. Simultaneously, the new resis-tance resources will be explored extensively and the new broad-spectrum resistance genes will be transfered into leading cultivars purposefully.