马铃薯疮痂病菌Streptomyces acidiscabies鉴定及抑菌有机酸筛选

本研究旨在鉴定微型薯连作基质中疮痂病原菌的种类,筛选具有良好抑制活性的有机酸以利于控制疮痂病发生。研究从病薯上分离纯化病原菌,用薯片法、萝卜片法及温室盆栽接种法检测其致病性,结合形态学观察、生理生化特性测定及16S rRNA基因序列分析确定种类,对其耐盐性等生物学特性进行研究,用纸碟法测定甲酸等有机酸对疮痂链霉菌生长的影响。链霉菌19311具有致病性,其致病岛毒力相关基因型为txtAB+/tomA+/necI+,根据19311菌株培养特征、生理生化特性及16S rRNA序列分析结果鉴定为酸性疮痂链霉菌(Streptomyces acidiscabies)。甲酸、乙酸、丙酸、乳酸、柠檬酸、酒石酸可显著抑制S.acidiscabies的生长,甲酸抑菌效果最佳,抑菌圈直径为45.43 mm,抑菌最低有效浓度为1%,可通过增加细胞膜通透性抑制S.acidiscabies生长。综上所述,本研究明确了微型薯生产基质中疮痂链霉菌19311的种类及其生物学特性。未来可考虑使用1%甲酸进行疮痂病的控制试验,并评估其对原原种生产的潜在影响。

Study on Purification and Properties of Antibacterial Substance from Antagonistic Bacteria P72 against Wheat Scab

[Objective] The study aimed to explore the antibacterial activity and stability of antagonistic bacteria P72 against wheat scab.[Method] The Bacillus subtilis P72 was inoculated into fermentation media with the inoculation amount 5%,then cultured on shaking table at 28 ℃ for 48 h and centrifuged at 8 000 r/min for 10 min.The supernatant of fermentation broth was purified and then the genetic stability,thermal stability and pH stability were detected.[Result] By DEAE-52 ion exchange chromatography,the protein eluted by 0.5 mol/L NaCl solution possessed the strongest antagonistic ability against wheat scab pathogen.The SDS-PAGE electrophoresis showed that the molecular weight of the purified protein with antibacterial effect was 40 kD.By stability test,the antibacterial substance produced by P72 strain showed heritable antagonistic activity,high stability below 60 ℃,stability to acid and unstability to alkali.[Conclusion] The antagonistic bacteria P72 had strong antagonistic ability to wheat scab pathogen,stable antibacterial activity and thermal stability,so it would possess a wide development prospect.

Inhibition Effects of Different Trace and Secondary Elements on Scab of Cucurbits(Cladosporium cucumerinum) and Their Effects on Enzyme Activities of Cucumber Plants

The paper was to explore the effect of trace and secondary elements on scab of cucurbits （ Cladosporium cucumerinum） and their effects on enzyme activities of cucumber plants. [ Method ] Indoor antifungd experiment and pot test was carried out to study the control effect of different trace and secondary dements on scab of cucu.rbits; after trace and secondary element compounds were sprayed for 7 d, the content of soluble protein and malondialdehyde （MDA） and the activities of peroxidase （POD） and superoxide dismutase （SOD） of cucumber leaves during seedling stage were simultaneously detected. [ Result] The inhibi- tion effects on scab of cucurbits were found in the three trace and secondary dements, especially for the CaC12 （66.9%）, and about 54.6% and 24.1% for ZnSO4 and H3 BO3 , respectively. When cucumber plants were infected by scab of cuea.rbits, the contents of MDA for all treatments were significantly decreased in cucum- ber leaves after spraying the three trace and secondary elements compared with control. The contents of soluble protein in cucumber seedling were increased by Zn- SO4 and H3 BO3 application, while the contents of POD and SOD were increased on ZnSO4 and CaCI2 treatments. The defense system of cucumber was induced and strengthened by application of the three trace and secondary elements. [ Conclusion ] The results provided the theoretical basis for practical application and research on resistance mechanism of using trace and secondary dements to control scab of eueurbits.

马铃薯疮痂病菌Streptomyces scabies拮抗细菌筛选及鉴定

为获得对马铃薯疮痂病菌(Streptomyces scabies)具有拮抗效果的细菌菌株,从黑龙江省齐齐哈尔市克山农场马铃薯疮痂病发病地块健康植株根际土壤中分离得到181株细菌菌株,采用平板对峙生长法和牛津杯试验法对分离得到的菌株进行初筛和复筛,获得1株对S. scabies具有明显拮抗效果的菌株BKS51,抑菌圈直径达到37 mm,盆栽防效达到81.0%。对BKS51进行形态特征、生理生化特征测定以及16S rRNA、gyrB基因序列分析,并进行抑菌谱测定。结果表明,菌株BKS51的菌落为圆形、乳白色、不透明,表面有褶皱状凸起,边缘不整齐,菌体杆状、革兰氏阳性菌,硝酸还原反应呈阳性、葡萄糖发酵反应及MR反应呈阴性,结合16S rRNA和gyrB基因序列分析结果,将其鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。BKS51对多种植物病原菌均具有抑制效果,其中对玉米圆斑病菌(Bipolaris zeicola)和水稻胡麻斑病菌(Bipolaris oryzae)的抑制率较高,分别达到67.2%和62.4%。

Control Effects of Different Fungicides on Pear Scab

[Objective] The paper was to select different fungicides for field efficacy test against pear scab in summer.[Method] Five treatments were designed in the test,including 10% difenoconazole WDG 6 000 times dilution,50% captan WP 600 times dilution,30% pyraclostrobin SC 2 000 times dilution,430 g/L tebuconazole 4 000 times dilution,and water(control).[Result] 10% Difenoconazole WDG 6 000 times dilution,50% captan WP 600 times dilution,30% pyraclostrobin SC 2 000 times dilution,430 g/L tebuconazole SC 4 000 times dilution had good control effects against pear scab,and the efficacies were 89.13%-93.51%.[Conclusion] The results will provide the theoretical basis for field control of pear scab in summer.

Prevalence Reasons and Monitoring Countermeasures of Scab in Eastern Wheat Area of Jiangsu Province

With the increasing prevalence frequency and aggravating harm degree in the 21st century, wheat scab had become a recurrent disease in eastern wheat area of Jiangsu Province. This paper reviewed general occurrence situation of wheat scab in eastern Jiangsu, and summarized its occurrence characteristics in last decade. The disease prevalence was elaborated from the aspects of fungal source quantity, chmatic conditions, cultivation modes, variety resistance and pesticide resistance. The author put forward a series of measures and countermeasures, including strengthening resistance monitoring and early warning, promoting and cultivating disease-resistant varieties, compressing planting area of direct seeding rice, canting out chemical control scientifically, and realizing unified prevention and control, in order to provide a scientific basis for the control of wheat scab.

Preliminary Study on Control Effects of Five Kinds of Fungicides against Wheat Scab

[Objective] This paper was to improve the current status that the fungicide carbendazim as the single agent was largely applied in the control against wheat scab. [ Method] Five kinds of fungicides on sales and new agents against wheat scab were selected for field trials. [ Result] 25% JS399 - 19 SC, 30% te- buconazoh · thiram WP, 75% trifloxystrobin · tebuconasole WDG and 10% ZJ0712 JG could effectively control wheat scab, and the control effects of one time or two times application were better than control agent carbendasim; the control efficacy of two times application was improved in different degrees against one time ap- vlication. [ Conclusion] The naner vrevided basis for the control atminst wheat scab.

Changes of Physiological Characteristics and Yield in Peanut Varieties with Different Resistance Effected by Peanut Scab

In order to identify the resistance of peanut varieties against scab disease, the changes of physiological characteristics and yield in two peanut varieties ＇Heyou 13＇ and ＇Quanhual0＇ with different resistance effected by peanut scab were stud- ied in field experiment by spray. The results showed the soluble sugar increased firstly and then decreased both in the resistant and susceptible peanuts after inocu- lation. Compared with the control, the soluble sugar of resistant peanut was higher, and that of the susceptible peanut was lower, which implied that the peanut resis- tance to scab was positive correlated with soluble sugar content. The soluble pro- tein content in leaves of resistant and susceptible peanut varieties after inoculation was higher than that of the control. The peak of soluble protein content appeared earlier in the susceptible peanut than in the resistant peanut, which indicated that the susceptible peanut were more sensitive to the pathogen than the resistant peanut. The leaf SOD activity increased firstly and then decreased both in resistant and susceptible varieties, while the decrease in the resistant variety were lower than in the susceptible variety. With the growth process, the CAT and POD activities first decreased, then increased, and again decreased. Compared with the corresponding control, the resistant variety had relatively higher CAT and POD activities than the susceptible variety, which illustrated that the protective enzymes played important roles in resistance mechanism to scab. The MDA content of the two peanut vari- eties after inoculation increased, indicating that plasma membranes were subjected to different degrees of damage. The yield of resistant and susceptible varieties after inoculation reduced, while the yield of the susceptible peanut of ＇Quanhua 10＇ reduced greater.

有限 M-SCABS 与 Buildings

本文给出了一个有限Ｍ－ＳＣＡＢ是Ｂｕｉｌｄｉｎｇ的充要条件及一个有限Ｍ－ＳＣＡＢ的万有覆盖是Ｂｕｉｌｄｉｎｇ的充要条件

Induction of Systemic Resistance in Cucumber(cucumissatssivus)against Scab with BION,an Activator of Systemic Acquired Resistance

The cucumber scab caused by Cladosporium cucumerinum Ell. is one of the most important diseases of cucumber in the PR. of China and elsewhere. Recently, wider acceptance of under glas culture exacerbates the problem. Both in greenhouses and in free fields in the Northern China pose a challenge in the control of this disease, because there are no effective fungicide to be used. Induced resistance with chemicals may be an ideal way to protect cucumber against this disease , if there are no resistant cultivars to be used. This paper reports the effect of BION, a new activator of SAR, on the induction of resistance to cucumber scab using two treatment methods (seed treatment and foliar spray) at different concentrations (10,20,40, 80, 160 mg. mL- 1). The results showed that the number of diseased plants was decreased drastically in BION - treated plants, the disease incidence was 35 %, whereas it was 75 % in control plants. The disease severity of plant with BION treatment by foliar spray was 2 and it was 1.5 if used as seed treatment, whereas it was 3 and 3.1 in control plants respectively. Moreover it has no phytotoxic effect to be observed at concentrations used in the experiment.

Coupling Induction of Wheat Scab,Gibberella zeae

Based on the survey of observation, the factors afffecting prevalence degree of wheat scab （ Gibberella zeae） were analyzed through coupling method. The results showed that the average diseased ear rate before harvest （disease index） was associated with the average relative humidity from April to early May, the average temperature from April to early May, and the interval from peak maturity stage of perithecium to full heading stage of wheat. The interval was used to measure the coincidence degree between release period of ascospore and ear period （ heading to grouting stage）. The prevalence of wheat scab was determined by coincidence degree and meteorological conditions of ear period. Quantitative prediction should be conducted, to improve prediction and control levels.

Scab Disease Caused by <i>Venturia inaequalis</i>on Apple Trees in Kyrgyzstan and Biological Agents to Control This Disease

Among the most economically important fruit crops in South and North Kyrgyzstan affected by scab disease are apples (Malus domestica). Natural isolates of Venturia inaequalis were isolated from diseased parts of apple trees, selected from different regions, through sedimentation of air microflora on the crowns of fruit trees. Two biocontrol agents as Trichoderma viride and Streptomyces sр. were tested for apple scab control in vitro and field conditions. Two applications of Trichoderma viride within 35 days completely stopped the scab disease in seedling leaves. Within 40 days, the seedlings were recovered;the new leaves have blossomed on branches. The Streptomyces sp. antagonists were inferior in effectiveness compared to Trichoderma viride;nevertheless, they prevented progression of the disease in the leaves. Seedlings grew new shoots and leaves around 50 days after the second treatment. Orchard experiment results provide great hope that a biological product based on Trichoderma viride could work as an effective agent to suppress the development of the pathogen in the early spring, when leaves start to show scab disease symptoms.

Identification and Prevention and Control of Scab-anthracnoge of Landscape Plant Fatsia japonica

The pathogenic characteristics of scab-anthracnoge of Fatsia japonica was introduced,and the infection cycle,occurrence regularity and main harmful symptoms of the disease were elaborated.Prevention is the main method to prevent scab-anthracnoge of F.japonica,and disease-free seedlings should be cultivated.Meantime,cultivation management should be strengthened to improve disease resistance of plant,and chemical agents must be timely sprayed in the early incidence stage,in order to achieve the purpose of comprehensive control.

Innocuous-looking skin scab over an arteriovenous fistula: Case report and literature review

Little is written on the management of an innocuouslooking skin scab over an autogenous arteriovenous fistula(AVF)used for haemodialysis.The seriousness of the underlying pathology can be under-estimated,and this may lead to early loss of the AVF,and majorlife-threatening haemorrhage.We describe the management of a 78-year-old patient presenting with an innocuous-looking scab over an AVF and review the pertinent literature on this subject.

Preparation on the basis of Trichoderma asperellum in the system of biological protection of wheat from Fusarium ear scab

During the last century, as the area of wheat grown under advanced grain husbandry has increased worldwide, so too has the importance of Fusarium ear scab (FES) (synonym, Fusarium head blight) caused by several species of the fungus Fusarium. Yield losses due to FES can total 20%-40% and more depending on climatic conditions. During the last twenty years epidemics of FES in cereals have become chronic all over the world, including the United States and Russia. The most destructive of these were observed in 1982, 1986, 1990-1996 in USA and in the south of Russia in 1982, 1984, 1988, 1992. The harmful effect of FES is manifested not only in reduced grain yields, but also in the contamination of grains and grain products with mycotoxins, such as deoxynivalenol (DON) and its derivatives (3-alfa acetyl-DON, 15-alfa acetyl-DON), T-2 toxin and zearalenone. Standard means to control FES (cultural control methodologies, chemical pesticides, and FES resistant varieties) have little effect or are not practical and rarely reduce the accumulation of mycotoxins in grain. We have developed a new technique to reduce FES using biological preparations. The technique utilizes wheat seed pretreatment with a biofungicide “Mycol” in combination with spraying wheat plants during flowering with a yeast preparation. Technology for production of Mycol on the basis of Trichoderma asperellum strain GJS 03-35 (systematics by Samuels) has been developed. This strain shows hyperparasitic activity against a wide spectrum of plant pathogens, including Fusarium graminearum, a causative agent of FES in wheat. Experiments conducted in the United States demonstrated that spraying wheat plants during flowering with the patented yeast Cryptococcus nodaensis OH 182.9 (NRRL Y-30216) reliably reduces FES development. Tests of the Mycol preparation and the yeast OH 182.9 (EOD) have been performed on the spring wheat “Ivolga” in greenhouse conditions (the Moscow region) and on the winter wheat “Kupava” in field trials in the North Caucasian region. An isolate of F. graminearum was used to insure adequate levels of disease development in greenhouse and field experiments. FES disease severity and incidence, as well as mycotoxin accumulation in wheat grains was studied for single or combination treatments with the biological preparations. Mycol (in concentrations 0.1, 0.5, 1.0, 2.0 kg/t of seeds) was used for wheat seed pretreatment. The yeast preparation EOD (2.0×107 cfu/mL) was applied by spraying wheat plants during flowering. Chemical pesticides (Raxyl, TMTD) and a biological preparation Agat-25K were used as alternative control seed treatments. In greenhouse experiments, inoculations of heads with either biological preparation 4 h prior to inoculation with conidia of F. graminearum significantly reduced FES severity. Application with Mycol reduced DON in wheat grains by 6 to 11 fold. EOD alone or, to a lesser extent, in combination was also highly effective in reducing DON content. For treatments consisting of Mycol and EOD, 1000 grain weights were equivalent or higher than for control plants (both infected, and not infected). Wheat seeds obtained from the plants protected by these biological preparations germinated rapidly and possessed high germination rates compared to the FES control. In field trials, Mycol treatments clearly reduced FES symptoms, apparently providing an immunizing effect against FES. Mycol reduced FES severity and enhanced yield of the wheat varieties used. The effect of Mycol used at a minimum test-dose (0.1 kg/t) was not so pronounced. The greatest reduction of FES development was observed at a dose of Mycol of 1.0 kg per 1 t of seeds used in combination with EOD spraying. Experimental results support the contention that the offered technology has good prospects in controlling wheat Fusarium ear scab.

Detection of scab in wheat ears using in situ hyperspectral data and support vector machine optimized by genetic algorithm

A new method was proposed to extract sensitive features and to construct a monitoring model for wheat scab based on in situ hyperspectral data of wheat ears to achieve effective prevention and control and provide theoretical support for its large-scale monitoring.Eight sensitive features were selected through correlation analysis and wavelet transform.These features were as follows:three original bands of 350-400 nm,500-600 nm,and 720-1000 nm;three vegetation indices of modified simple ratio(MSR),normalized difference vegetation index,and structural independent pigment index;and two wavelet features of WF01 and WF02.By combining the selected sensitive features with support vector machine(SVM)and SVM optimized by genetic algorithm(GASVM),a total of 16 monitoring models were built,and the monitoring accuracies of the two types of models were compared.The ability of the monitoring models built by GASVM to identify scab was better than that of SVM algorithm under the same characteristic variables.Among the 16 models,MSR combined with GASVM had an overall accuracy of 75%and a Kappa coefficient of 0.47.GASVM can be used to monitor wheat scab and its application can improve the accuracy of disease monitoring.

Effectiveness of population improvement through recurrent selection for scab resistance in wheat using dominant male-sterile gene ms2

An original base population with wide genetic variability was developed by multiple-parent cross- ing,intermating and recrossing using the dominant male-sterile gene ms2(Tal).Then the phenotypic recurrent selection was conducted for the male-sterile plants in order to improve the population and develop a gene pool with increased resistance to scab in wheat.Generations RC_0-RC_2 and RC_1-RC_5 from the resistance resource pool were evaluated for the resistance and the effect of population improvement was analyzed in Nanjing under soil-surface inoculation with F.graminearum-diseased seeds in 1988/1989 and single-floret inoculation with ascospore suspension of G.zeae in 1991/1992,respectively.The experimental results of the soil-surface inoculation indicated that the numbers or percentages of diseased spikelets and seeds per spike of the male-fertile plants were decreased significantly and the comprehensive resistance of the population to scab was obviously increased.The percentages of uninfected seeds per spike in generations RC_0,RC_1 and RC_2 were 49.2%,65.5% and 70.7%,respectively.The frequencies of plants with lower than 30% of diseased spikelet and seed percentages in the population were increased by 40% and 36%,respectively,through 2 cycles of se- lection.Under the condition of the single-floret inoculation,the results further demonstrated that the resistance to the fungal spread could be improved significantly through the phenotypic recurrent selection.The opportunity of obtaining superior resistant plants from the population would be enhanced gradually with the development of the gene pool.On average,from RC_1 to RC_5,the population mean of diseased spikelets of inoculated spikes was reduced by 8.6% and the frequency of resistant plants with fewer than 4 diseased spikelets per inoculated spike was increased by 4.2%,respectively,per cycle.The frequency of susceptible plants with more than 10 diseased spikelets in inoculated spikes was decreased by 9.2% after 4 cycles of se- lection.The genetic variance for resistance reduced remarkably but no significant decrease in the genetic coefficient of variation was found during the first 4 cycles of selection.

THE MUTANTS OF SCAB-RESISTANT WHEAT SELECTED BY CELL CULTURE

Breeding of scab-resistant wheat is a very difficult subject. It is urgent to probe a new breeding technique. In recent years, the results from some tests indicated that resistant mutants selected by cell culture may be very hopeful. In comparison with plant level selec-

马铃薯疮痂病菌Streptomyces scabies拮抗细菌的筛选及BKS104鉴定

【背景】近年来,马铃薯疮痂病的危害态势逐渐上升,在全国各主要产区均有发生,目前由于缺乏有效的防治手段,已造成了严重的经济损失。生物防治是防治土传病害的有效途径,逐渐成为了研究热点。【目的】筛选对马铃薯疮痂病菌具有较高拮抗效果的菌株,为生防菌剂的开发提供菌种资源,同时也为马铃薯疮痂病的防治奠定理论基础。【方法】采用平板对峙法和牛津杯试验法对分离得到的菌株进行初筛和复筛,并通过形态特征、生理生化特征及16S rRNA基因、gyrB基因序列分析结果对菌株进行鉴定。通过平板对峙法测定菌株的抑菌谱。【结果】获得一株具有明显拮抗效果的菌株BKS104,抑菌直径达到43mm,防效达到85%。其菌落圆形、乳白色、不透明、表面有光泽,边缘整齐,菌体杆状,革兰氏阳性菌。结合16S rRNA基因、gyrB基因的测序结果将其鉴定为贝莱斯芽孢杆菌,并对8种植物病原真菌均具有抑制效果。【结论】菌株BKS104为贝莱斯芽孢杆菌,可以有效抑制马铃薯疮痂病菌的生长,安全性高,具有良好的生防潜力。

Influence of alloplasm on resistance to wheat scab

Using alloplasmic wheat as test materials, the genetic effect of cytoplasm on wheat scab resistance was studied by three methods including the determination of resistance of explant calli to Gibberella zeae toxin, the identification of inoculating single fixed position and the identification of field resistance. The results showed that among "the homonucleo_heterocytoplasmic lines", resistance of calli to G. zeae toxin was different; the difference of cytoplasmic effect among different nucleoplasm combinations showed certain nucleoplasm interaction relation. Resistance of hybrid F 1 plants of reciprocal cross between alloplasmic line and disease-sensitive wheat variety to wheat scab was of clear difference. Hybrid F 1 of reciprocal cross between Ae. ventricosa cytoplasmic wheat and disease-sensitive or -resistant wheat variety all exhibited fine resistance effect of alloplasm. Compared with general common wheat variety, most alloplasmic wheats tested have stronger resistance. A few selected lines having Ae. ventricosa cytoplasm have a strong and stable resistance to scab. They can be a finer new resistant source.