The effects of the root diffusate of different crops from different rotation systems on the egg hatch of soybean cyst nematode Heterodera glycines
XU Yan-li1,2£¬CHEN Yi-li2£¬SI Zhao-sheng1£¬LI Zhao-lin1£¬LI Chun-jie1£¬WEN Guang-yue1
(1. Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Harbin 150040, China; 2 .Northeast Agricultural University, Harbin 150030 China)

Abstract: The effects of 5 crops from 5 rotation systems and fallow soil on egg hatch of H. glycines were determined under laboratory conditions. Crops tested included soybean, corn, wheat, flax and sugar beet. Five rotation systems were wheat-ª²soybean-wheat(WSW),soybean-wheat-corn(SWC),corn-soybean-corn(CSC),soybean-wheat-soybean (SWS), continuous soybean (SSS¡­S 12 years). Root diffusate from sugar beet on WSW, SWS and SSS¡­S 12 years caused greater hatch of H.glycines than other crops on the same rotation system. Diffusate from soybean root on SWC and corn root on CSC stimulated the egg hatch more than any of the other crops on the same rotation system. Root diffusate from 5 crops on fallow soil also stimulated egg hatch of H. glycines.
Key words: crops; rotation; continuous cropping;root diffusate; Heterodera glycines; egg hatch

Molecular cloning of two Mn superoxide dismutase genes from Bacillus cereus M22 and their expression in Escherichia coli
SHANG Yu-lei1, CHEN Hui-fang2, WANG Li-ming2, WANG Yong-jun2, WANG Qi2ª³, ZHANG Bing-xin1, MEI Ru-hong2
(1. College of Agricultural and Biotechnology, Zhejiang University, Hangzhou 310029, China; 2.College of Agronomy and Biotechnology, China Agricultural University, Beijing 100094, China)

Abstract:Two complete sequences of Mn-containing superoxide dismutase (Mn-SOD) genes, sodA1 and sodA2, were cloned from endophytic Bacillus cereus M22 by using direct PCR and inverse PCR(IPCR). Nucleate sequencing revealed that the open reading frame of sodA1 and sodA2 consisted of 218 and 208 amino acids, respectively. The deduced proteins, which had the highly conserved Mn-SOD motif, shared high identity with the previously isolated members of Mn-SOD family. However, SODA1 and SODA2 had a lower identity to each other. These two SOD genes were inserted into the expression vector pET-22b(+) and the recombinant proteins were expressed in E.coli BL21(DE3) at a high amount as the soluble protein. Transformation of pET-sodA into E. coli QC779, a double mutant devoid of Mn-SOD and Fe-SOD activities, recovered the SOD deficiency and the transformant could grow on the LB plate containing 10 ¦Ìmol/L paraquat. SODA1 and SODA2 were sensitive to potassium cyanide(KCN) and hydrogen peroxide (H2O2) indicated that they used manganese(Mn) as a cofactor.
Key words£º Bacillus cereus; Mn superoxide dismutase genes; molecular cloning; sequencing; expression in E. coli

Identification of a nematode isolate from wilt Pinus massoniana
YANG Pei-wen1,2, WANG Feng1, WANG Yang1, FENG Shi-ming3, XU Zheng-hui4, YU Sheng-fu1
£¨1. Key Laboratory for Plant Pathology of Yunnan Province, YAU, Kunming 650201, China; 2. Institute of Plant Protection, Yunnan Academy of Agricultural Sciences, Kunming 650205£¬ China; 3 .Quarantine and Control Station for Forest Disease and Insect of Yunnan Province, Kunming 650051, China; 4. Faculty of Protection Biology, Southwest Forestry College, Kunming 650224, China)

Abstract: Wilt pine samples were collected from Guiyang in 2002. Morphological and molecular identification of the nematode which isolated and purified from the sample were carried out. The morphological identification showed that characteristics of the nematode was similar to what Mamiya reported. Polymerase Chain Reaction ( PCR) amplification of the internal transcribed spacer (ITS) of the ribosomal DNA of the samples was done with universal primers VRF1(5¡äCGTAACAAGGTAGCTGTAG 3¡ä) and VRF2 £¨5¡äTCCTCCGCTAAATGATATG 3¡ä£©, and the PCR products were cloned into pGEM-T vector. Sequencing results showed that the homology between the samples and Bursaphelenchus xylophilus(Nanjing) was 77.6%, and shared 93.5% and 97.9£¥ homology with U93554 (B. mucronatus sequence in GenBank) and 3 populations of B. mucronatus isolated from Yunnan, respectively. The results revealed that the nematode isolate from Guiyang was B. mucronatus.
Key words: Pinus massoniana; wilt disease; Bursaphelenchus mucronatus; morphologic identification; ITS analysis

Research on the relationship between maize resistance to RBSDV and defense isoenzymes
LIANG Qiong1£¬ HOU Ming-sheng2*
(1. Wuhan Institute of Botany, CAS, Wuhan 430074£¬ China; 2. Plant Science and Technology Academy, Huazhong Agricultural University, Wuhan 430070£¬ China)

Abstract: Based on the previous study on the molecular identification of Rice black-streaked dwarf virus (RBSDV), this research was performed for further understanding of the relationship between resistance of maize to RBSDV and the expression of defense -related isoenzymes. Three representative maize varieties with different resistant level to RBSDV were selected from more than 60 varieties in field. The investigation showed that peroxidase (POD) isoenzymes expressed in obviously different patterns in the resistant and susceptible varieties. Both constitutive and virus-inducible expression of POD were found in all tested varieties,in which the constitutive expression might contribute to the host resistance. Expression of esterase (EST) isoenzymes varied in different developmental stages, but showed the same pattern in the resistant and susceptible varieties. Polyphenol oxidase (PPO) isoenzymes were stimulated by the virus infection and the enzyme expression also varied with the maize developmental stages. These results suggest that isoenzyme expression of POD, EST and PPO is developmentally regulated and varied with the maize varieties and virus infection.
Key words: Rice black-streaked dwarf virus; defense enzyme; isoenzyme

Mechanisms of resistance to gray mould in tomato plant induced by antagonistic bacteria
TONG Yun-hui1, GUO Gui-ping2, XU Jing-you1, JI Zhao-lin1, CHEN Xi-jun1
(1. Department of Plant Protection, Agricultural College, Yangzhou University, Yangzhou, Jiangsu 225009, China; 2.Nantong Entry-Exit Inspection and Quarantine Bureau, Nantong, Jiangsu 226005, China)

Abstract: Systemic resistance in tomato leaves against Botrytis cinerea could be induced by the antagonistic bacterium Paenibacillus polymyxa W3 and its culture filtrate. After the treatment with W3 or its culture filtrate, the activities of phenylalanine ammonia-lyase (PAL), peroxidase (POD), polypenoloxidase (PPO) and superoxide dismutase (SOD) in tomato leaves increased obviously. The activities of PAL and SOD peaked 1 day after the treatment while the activities of POD and PPO reached their maximum 3 days after the treatment. Compared with control, PAL, POD, PPO and SOD in treated leaves kept higher activities for 6 days during the experiment. O2- production rate in treated leaves reached the peak 1 day after inoculation and showed 85.6%-88.6% higher than that in the control. Salicylic acid (SA) was found increasing significantly and showed 1.6 fold and 2.6 fold higher in treated leaves and their upper leaves£¬ respectively, in comparison with the leaves in un-inoculated control. The results indicated that SA could be involved in the induction of systemic resistance triggered by the antagonistic bacterium and its culture filtrate.
Key words: Paenibacillus polymyxa; induced resistance; PAL; POD; PPO; SOD; AOS; SA; Botrytis cinerea

Biochemical indexes for resistance estimation of grape variety to downy mildew
LU Xiu-lan1£¬ GOU lin2£¬ GONG Rong-gao1£¬ ZHANG Guang-lun1
£¨1. College of Forestry and Horticulture£¬Sichuan Agricultural University£¬ Ya'an 625014£¬ China£» 2. College of Biology and Science£¬ Sichuan Agricultural University£¬ Ya'an 625014£¬ China£©

Abstract: One highly resistant variety£¬Fujiminori£¬and eight moderately resistant varieties, are Fanganghei, Shingno Smile, Flame Seedless, Heimi, Youxuanpiaonai, Gaoqi, Jingxiu and Fenghou were selected from 22 grape varieties tested through the inoculation test in pots and natural infection experiments in field. There was very significantly negative correlation between disease indexes of downy mildew and several enzyme activities including PPO and PAL as well as CAT specific activity in these 22 varieties tested before or after inoculation. But SOD enzyme activity was not quite correlated with disease index of grape downy mildew. PPO and PAL enzyme activities and CAT specific activity of grape were related to its resistance of downy mildew significantly. The results suggested that these three enzyme activities could be used as one of indexes for resistance estimation of grape to downy mildew.
Key words£ºgrape variety£» downy mildew£» resistance£» biochemical indexes

Impact of herbicides on two kinds of arbuscular mycorrhizas
DONG Chang-jin1,2, ZHAO Bin1ª³
£¨1. State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; 2. The Department of Biology, Hubei Normal University, Huangshi 435002, China£©

Abstract: In pot experiments, the trail results showed that herbicides of acetochlor, butachlor, glyphosate-isopropylammonium, aventis and quizalofop-pethyl reduced significantly the biomass of soybean, infection rates of AM fungus, mycelium enzyme activity of ALP and SDH, and total mycelium amount of AM fungi in the soil. After treatment for 6 weeks, acetochlor and butachlor decreased remarkably the biomass of soybean (the biomass was 12.6¡ª15.5 g), however, quizalofop-p-ethyl had the less impact on biomass of soybean (the biomass was 20.8¡ª23.5 g), and the biomass of trail control was 29.5¡ª30.8 g; butachlor reduced significantly the infection rates of AM fungi (AM fungal infection rates were 17.4%¡ª24.1%), acetochlor and glyphosate-isopropylammonium had the less impact on the infection rates of AM fungi (the infection rates were 29.3%¡ª32.2%), while the infection rates of the controls were 78.5%¡ª62.4%; butachlor also influenced significantly the enzyme activity of AM mycelium ALP and SDH (ALP were 10.2%¡ª13.6%, SDH were 13.5%¡ª18.8%), acetochlor and glyphosate-isopropylammonium had the less impact on the enzyme activity of AM fungi mycelium ALP and SDH (ALP was 13.9%¡ª17.8%, SDH was 19.8%¡ª25.0%), while the mycelium ALP of the control was 47.0%¡ª36.3%, the mycelium SDH of the control was 62.7% ¡ª48.4%; besides, herbicides also reduced significantly total mycelium amount of AM fungi in the soil.
Key words: herbicides; AM fungi; infection rate; SDH£» ALP

Induction of oligosaccharide to ultrastructure of cucumber resistance to powdery mildew fungus
MA Qing1, SUN Hui1, DU Yu-guang2, ZHAO Xiao-ming2, SHANG Hong-sheng1
(1. College of Plant Protection, Northwest Sci-Tech University of Agriculture and Forestry, Yangling, Shaanxi 712100, China; 2 .Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China)

Abstract: Five days after being treated with amino oligosaccharin, the cucumber leaves were inoculated with cucumber powdery mildew, Sphaerotheca fuliginea (Schlecht.) Poll., to induce the cucumber resistance to powdery mildew. The host cells produced defense structures and material related to infection and hypersensitive response. The host cell wall was thickened and deeply stained, several layers of papilla structure produced under the cell wall, dark material deposited between the cell wall and plasmalemma; extrahaustorial plasmalemma deeply stained and extrahaustorial matrix appositions deposited with large amount of electronª²dense material; cytoplasm disordered, host organelles disintegrated and finally the whole host cell disintegrated and necrotized.
Key words: cucumber; Sphaerotheca fuliginea; oligosaccharide; induced resistance;
Ultrastructure

Effects of fludioxonil on growth of watermelon seedlings and activity of disease resistance-related enzymes
WU Xue-hong, LI Fei-wu, ZHANG Wen-hua, LIU Peng-fei, ZHENG Le, LIU Xi-li
( College of Agronomy and Biotechnology, China Agricultural University, Beijing 100094, China)

Abstract£ºEffects of 2.5% Celest seed coating formulation (a.i. fludioxonil) were examined on the germination, growth and development of watermelon seedlings and the activity of disease resistance-related enzymes in watermelon seedlings. The results showed that the germination rate, the width of cotyledon, the number of sideroots and the fresh weight of one hundred seedlings did not change in coated seedlings. However, cotyledon and seedlings were 4.8% longer and 7.5% higher after treatment. Moreover, 7.7% decrease in accumulation of malondialdehyde(MDA) and 2.2£¥ increase in content of soluble protein were found through the coating treatment.The activities of peroxidase (POD), catalase (CAT), polyphenoloxidase (PPO) and phenylalanine ammonia lyase(PAL) in watermelon seedlings were 62.9%, 46.5%, 35.6% and 44.1% higher than those of the untreated, respectively. It was concluded that the germination of watermelon seeds treated by the chemical was safe, the growth and development of seedlings were promoted and the activity of diseases resistance-related enzymes was also increased.
Key words£ºfludioxonil£» watermelon£» growth and development£» disease
resistance-related enzymes

A new inoculation method for Verticillium wilt on cotton and its application in evaluating pathogenesis and host resistance
MA Ping1, H.C. HUANG2, LI She-zeng1, TANG Wen-hua3
(1. Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000£¬ China; 2. Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada, T1J 4B1; 3. Department of Plant Pathology, China Agricultural University, Beijing 100094£¬China)

Abstract: Three inoculation methods: cotton root injured and dipped in a spore suspension (106 conidia/mL), soil infested with Verticillium dahliae grown on wheat bran and corn meal (1¡Ã1 w/w) in the ratio of 0.5%, 1% and 2% (w/w), and soil infested with microsclerotia (103 microsclerotia/g soil), were compared in the greenhouse for their effectiveness in infection and development of Verticillium wilt of cotton. Results showed that, among the three inoculation methods, the root dipping was the most effective method as judged from symptom development. The entire test for the root-dipping method required 35¡ª45 days whereas the other two soil treatment methods required 75 days. For the root-dipping method, more severe disease was observed at the inoculum density of 105 or 106 conidia/mL than at 104 conidia/mL. The disease resistances of 12 cotton varieties or lines were assessed by the root-dipping method in the greenhouse. This study suggests that root inoculation of young cotton seedlings is a useful method for rapid screening of cotton cultivars/lines for resistance to Verticillium wilt. Meanwhile, this method is also useful in testing differences in pathogenicity of strains of V. dahliae from various hosts.
Key words: cotton£» Verticillium dahliae£» Verticillium wilt£» inoculation technique£» root-dipping method

Identification of resistance to yellow mosaic disease of wheat and analysis for its inheritance of some varieties
LIU Weihua1,3, HE Zhen-tian2, GENG Bo1, HOU Ming-sheng4, ZHANG Min5, NIE Huan1, HAN Yue-peng2,HAN Cheng-gui1, WANG Jin-rong2, YU Jia-lin1, CHEN Xiu-lan2
(1. State Key Laboratory of Agro-biotechnology, China Agricultural University, Beijing 100094, China; 2 .Jiangsu Lixiahe Region Institute of Agricultural Sciences, Yangzhou 225207, China; 3.Institute of Crop Germplasm Resources, CAAS, Beijing 100081, China; 4 .Department of Plant Protection, Huazhong Agricultural University, Wuhan 430070, China; 5. College of Agronomy, Sichuan Agricultural University, Ya¡¯an 625014, China)

Abstract: Wheat yellow mosaic disease resistance was identified in the field among thirty-seven wheat varieties derived from China (Jiangsu, Henan, Sichuan and Hubei Province), Japan and United States. By RT-PCR and ELISA detections, it was proved that the wheat variety ¡°Yangfu 9311¡± displayed immunity to Wheat yellow mosaic virus(WYMV). The variety was crossed and backcrossed with those that were susceptible to the disease. By screening for the resistance among the segregating populations of F2 and BC1, the inheritance studies indicated that the resistance of ¡°Yangfu 9311¡± was controlled by a pair of dominant monogene. These results provided theoretical basis and experimental materials to find molecular markers of the resistance gene. In this paper, the resistant phenotype of Ningmai 9 and the influencing factors for resistance to Wheat yellow mosaic disease were also discussed.
Key words: wheat; Wheat yellow mosaic disease; Wheat yellow mosaic virus; resistance; inheritance

A novel SCAR marker closely linked to the avirulence gene AVR-Pikm in rice blast fungus Magnaporthe grisea
ZHANG Guo-zhen#, LIU Jun-feng#, MA Qiu-juan**, PENG You-liang*
(Department of Plant Pathology£¬ China Agricultural University, Beijing 100094, China)

Abstract: Avirulence genes are functional genes in pathogens that determine expression of the race-specific resistance in hosts. By using the technique of random amplified polymorphic DNAs(RAPD), this study identified a new DNA marker OPE121400 that was closely linked to the avirulence gene, AVR-Pikm, in rice blast pathogen Magnaporthe grisea. Based on the nucleotide sequence of OPE121400, a pair of 17 nt primers was designed and used for PCR detection of DNA polymorphism in a mapping population, which was generated by crossing an avirulent strain S1522 with a virulent strain S159. A single DNA band with similar length to the RAPD marker OPE121400 was generated by the PCR in all the avirulent progenies but not in the virulent ones except for two recombinants.The genetic distance from the marker to AVR-Pikm was calculated as 1.89 cM, which was 2.86 cM closer to the gene than OPO121000, a RAPD marker previously identified by our group. Although lied in the same side with OPO121000, OPE121400 will be useful for locating the position of AVR-Pikm in the chromosome and orientating contigs for further screening of linked SSR markers that lie in the opposite side.
Key words: Magnaporthe grisea; avirulence gene; RAPD marker; SCAR marker

Research Notes

Interaction of chitinase isozyme and soybean resistant to Heterodera glycines
WU Hai-yan1, DUAN Yu-xi2
(1. College of Plant Protection, Shandong Agricultural University, Taian 271018, China; 2. College of Plant Protection, Shenyang Agricultural University, Shenyang 110161, China)

Preliminary study on production and application of antiserum against Ustilaginoidea virens
ZHANG Jun-cheng1,2£¬ CHEN Zhi-yi1*£¬ ZHANG Bing-xin3, LIU Yong-feng1£¬ LU Fan1
(1. Plant Protection Institute, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; 2. Agricultural College, Guangxi University, Nanning 530005, China; 3. Department of Plant Protection, Zhejiang University, Hangzhou 310029, China)

A new disease of luohanguo(Siraitia grosvenorii) caused by Ralstonia solanacearum¡ªbacterial wilt
LI Qi-qin1,2, LIN Wei1, FENG Jia-xun1, DUAN Cheng-jie1, YE Yun-feng1, XIE Yi-ling1, LUO Kuan2
(1. Guangxi University, Nanning 530005, China; 2. Hunan Agricultural University, Changsha 410128, China)