大豆抗锈病组织病理学研究

以抗感品种Ｐ１４５９０２５（Ｒ）和猴了毛（Ｓ）为试材，人工接种大豆锈苗后第１天起２天取样１次（共７次），石蜡切片及电镜扫描，大豆锈菌在抗感品种上均是从表皮角质直接侵入，侵入时均产生木质化，但抗病品种木质化速度快且数量大，抗病品种锈菌侵入后能产生乳状突起结构，且完成一次侵染至少需１４－１５天，而感病品种猴子毛则只需８－９天，接种后１３天产生的夏孢子堆感品种是抗病品种的２１．３倍，抗感品种间表皮叶毛形     

一种苗期鉴定烟草赤星病抗性的新方法

烟草赤星病抗性的高通量鉴定是快速筛选和培育烟草抗赤星病品种的前提条件。以15份对赤星病表现不同抗性水平的烟草种质为材料,采用链格孢菌菌饼接种苗期离体叶片,以发病叶片病斑面积作为抗性评价指标,对15份烟草种质的抗性进行评价,并与其田间成株期赤星病抗性进行比较分析。结果表明,采用苗期菌饼接种,供试15份烟草种质的病斑面积差异显著,感病品种病斑平均面积明显大于抗病品种;各品种苗期赤星病鉴定结果与成株期抗性鉴定结果基本一致,且苗期病斑面积大小与3个不同年份、同一地点的成株期平均病级指数间相关性均达到显著水平,分别为0.78、0.74和0.66。表明本研究探讨的苗期离体叶片菌饼鉴定法可以用于烟草赤星病早期鉴定,病斑面积可以作为评价指标准确反映不同烟草品种间赤星病的抗性差异。     

大豆种质资源对东北SMV1号和3号株系的抗性鉴定

采用556份大豆种质资源为供试材料,在2006和2007年连续两年分别接种SMV1号和3号株系,对其成株抗性和种粒斑驳抗性均进行了鉴定。结果表明,接种1号株系的成株抗病资源446份,占80．2％;抗种粒斑驳资源107份,占19．2％;对成株和种粒斑驳均表现抗性的资源103份,占18．5％。接种3号株系的成株抗病资源151份,占27．2％;抗种粒斑驳资源87份,占15．7％;对成株和种粒斑驳均表现为抗性的资源76份,占13．7％。对1号和3号株系,在成株和种粒抗性上均表现抗病的资源69份,占12．4％。以上资源特别是兼抗资源在大豆生产和抗病育种中应予以重视。研究还显示,来自辽宁和吉林的供试资源对1号和3号株系的成株和种粒抗性均较好;来自中国农科院作物所和黑龙江的供试资源对1号株系的成株抗性较好,但对1号和3号株系的种粒抗性相对较差。     

烤烟种质资源黑胫病抗性再鉴定

为精准鉴定国家烟草种质资源中期库中种质资源的黑胫病抗性,采用田间人工接种烟草黑胫病0号生理小种的方法,对77份原标记为抗病的烤烟种质资源进行了抗病性再鉴定。结果表明,大青筋和尖叶柳2份材料表现为高抗黑胫病;黑柳子等23份材料表现为抗黑胫病,其中大黑柳、胎里肥2412、弯梗子、大白筋0522、大黄金0295和黄苗二苯烟2221的抗性强;落地黄等20份材料表现为中抗黑胫病;中感黑胫病和高感黑胫病材料各12份;8份材料表现为感黑胫病。对25份抗性材料进行农艺性状鉴定和遗传多样性分析表明,供试种质遗传多样性丰富,其中叶宽的遗传多样性指数最高。研究结果为烟草黑胫病抗性育种提供了材料基础。     

银杏叶提取液诱导采后猕猴桃对青霉病的抗性机制

用类黄酮含量分别为0.25、0.50、0.75 mg/mL的银杏叶提取液（extract of Ginkgo biloba leaves,EGb）通过损伤接种的方法处理猕猴桃,以无菌水为对照,24 h后接种扩展青霉（Penicillium expansum）孢子悬浮液,通过测定病斑直径和发病率观察EGb诱导猕猴桃抗性的效果;用类黄酮含量为0.50 mg/mL的EGb处理猕猴桃后接种青霉孢子悬浮液,定期取样测定抗病相关防御酶、病程相关蛋白、类黄酮、总酚及丙二醛含量的变化。结果表明：0.50 mg/mL的EGb能有效控制猕猴桃果实接种青霉菌后的发病率,抑制病斑扩展,提高猕猴桃果肉多酚氧化酶（PPO）、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）、几丁质酶（CHI）和β-1,3-葡聚糖酶（GLU）活性,促进总酚和类黄酮的积累,同时降低膜脂过氧化程度,减少丙二醛的产生,其中以EGb处理后再接种青霉菌的抗性诱导效果最好,表明0.50 mg/mL的EGb可能以Priming机制诱导猕猴桃对青霉菌的抗性。     

花生品种资源的收集保存鉴定

至１９９０年，共收集花生种质资源４３２９份，其中４１５０份完成了繁种入库任务，并开展抗病性和品质鉴定分析工作，鉴定出抗锈病资源２５５份，抗早斑病２２２份，抗晚斑病９２份，抗根结线虫病２份，抗青枯病８５份，抗锈兼抗早斑病的１７０份，抗锈兼抗晚斑病种质５１份，抗早斑兼抗晚斑病的５６份；抗三种叶部病害的４５份，抗青枯病兼抗根结线虫病的２份，通过蛋白质，脂肪，油／亚比分析筛选出蛋白质含量在３２％以上的２６     

寡糖对向日葵锈菌侵染的影响

为了明确寡糖对向日葵锈菌侵染的影响,在向日葵苗期用寡糖处理,观察接菌后锈菌夏孢子的萌发率和侵入率以及向日葵叶片的气孔开闭,并用甲苯胺蓝染色法对入侵位点酚类化合物的积累进行了检测。试验结果表明,与对照相比寡糖处理后锈菌夏孢子的萌发率和侵入率显著降低,而气孔关闭率显著升高。同时,在接种后12h时,大量的侵入位点产生了酚类化合物的积累,说明寡糖处理可以有效抑制向日葵锈菌的侵染。     

烟草赤星病抗性因素遗传的双列分析

对烟草赤星病两个抗性因素遗传的1／2＊7(7+1)双列杂交分析表明,病斑数量和病斑大小的遗传都符合加性-显性模型。病斑数量的遗传属部分显性类型,显性基因主要表现为减效;病斑大小的遗传属完全显性类型,显性基因为增效基因。1996、1997两年的田间试验结果和苗期离体叶片接种的结果基本一致。烟草对赤星病病菌侵入的抗性较抗病斑扩展的能力更容易通过品种间杂交传递给后代。配合力分析表明,一些组合具有较好的抗侵入特殊配合力,另一些组合具有良好的抗扩展特殊配合力。抗×感组合Beinhart1000-1×NC82两个抗性因素特殊配合力均较好,在抗病育种中有较高的利用价值。     

寡糖诱导向日葵抗锈病的信号转导途径

为了解寡糖诱导向日葵抗锈病过程中的信号转导途径,利用寡糖、水杨酸（SA）、茉莉酸（JA）预先喷雾处理向日葵叶片,1d后接种锈菌,通过对植株体内脂氧合酶（LOX）活性及SA含量的测定,并通过RT-PCR对SA、JA信号途径的标记基因PR5和PDF1.2等表达水平进行测定,初步确定诱导抗性表达的信号转导途径。结果表明：经寡糖诱导后,向日葵叶片内LOX活性降低,SA含量上升,且诱导水杨酸途径标记基因PR5表达量增加。结果说明寡糖诱导向日葵抵抗锈病主要与SA介导的信号途径有关。     

大豆品种Maple Arrow耐菌核病生化机制

以世界公认的菌核病抗性品种Maple Arrow以及感病品种合丰25为材料,在大豆V1期进行活体接种,比较不同抗感材料在接种核盘菌后的72h内6个时间点的菌丝扩展速度和4种生化酶活性,旨在明确MapleArrow抗菌核病的生化机制,为抗病育种提供依据.扫描电镜结果表明,抗感品种在侵染后0～72h对病原菌的抗性差异明显,接种前期病原菌在Maple Arrow叶片上的扩展速度明显低于合丰25.接种后期,Maple Arrow叶片病健交界明显,菌丝体周围寄主组织结构保持相对完整;合丰25叶片布满菌丝体,叶片结构崩溃.动态生化指标测定结果表明抗感品种在过氧化物酶（POD）、多酚氧化酶（PPO）、超氧化物歧化酶（SOD）和苯丙氨酸解氨酶（PAL）活性均不同程度的高于对照组.接种后24h Maple Arrow的PPO活性显著高于感病品种;接种后48h Maple Arrow的POD和PAL的活性增加幅度显著高于合丰25.由此得出结论,抗病品种Maple Arrow的保护酶系统对核盘菌侵染的响应比感病品种合丰25更为活跃,四种保护酶中的PPO、POD和PAL是两种抗性差异的关键因子,其中PPO主要作用于感染前期,POD和PAL主要作用于后期.     

Phenols in spikelets and leaves of field‐grown oats (Avena sativa) with different inherent resistance to crown rust (Puccinia coronata f. sp. avenae)

BACKGROUND: Avenanthramides, health‐beneficial phenols in oats, are produced in response to incompatible races of the crown rust fungus, Puccinia coronata, in seedlings of greenhouse‐grown oats. This study aimed to elucidate whether avenanthramides and/or other phenolic compounds, together with the activities of phenylalanine ammonia lyase (PAL), phenoloxidase (PO) and the avenanthramide biosynthetic enzyme hydroxycinnamoyl‐CoA:hydroxyanthranilate‐N‐hydroxycinnamoyl transferase (HHT), are associated with crown rust infection in mature field‐grown oats. Nine oat (Avena sativa L.) genotypes with wide variation in crown rust resistance were exposed to naturally occurring fungal spores during the growth period. RESULTS: In the spikelets avenanthramides as well as HHT activities were more abundant in the crown rust resistant genotypes, whereas p‐coumaric and caffeic acids were more abundant in the susceptible ones. In the leaves avenanthramides were not associated with resistance. Instead two unknown compounds correlated negatively with the rust score. Phenols released by alkaline hydrolysis and PAL and PO activities were not related to rust infection, either in spikelets or in the leaves. CONCLUSION: Because grains of crown rust‐resistant oat genotypes seemed to have higher endogenous levels of health‐promoting avenanthramides, use of resistant oats may contribute to a food raw material with health‐beneficial effects. Copyright © 2009 Society of Chemical Industry     

BIOLOGICAL VALIDATION OF TOMATO PULP CONTINUOUS HEAT PROCESS

This research validated the commercial process applied to tomato pulp (pH 4.3 and 8 Brix) packed in Tetra Brik packages. Spores of Bacillus coagulans and Neosartorya fischeri were selected as targets. The heat resistance of both microorganisms, tested independently, was compared. The redesigned thermal processes were carried out in a aseptic processing and tested by indirect inoculation and retrieval with spores immobilized in alginate/tomato balls. The results showed that processes for 30 s at 115C or greater did not allow the survival of heat‐resistant molds. For bacterial spores, processes for 30 s at 109C or greater showed no survivors. Although, 30 s at 115C will control both types of spoilage spores, concern for possible C. botulinum growth attributed to metabiosis in product with varying initial populations of molds and residual oxygen content dictated, a process recommendation of 60 s at 126C for safety reasons.     

烟草种质资源抗马铃薯Y病毒病基因型鉴定

  背景和目的  从作物种质资源中进行等位基因鉴定,特别是优异等位基因的发掘和应用,是使种质资源加速转变为基因资源的关键所在。  方法  采用苗期汁液摩擦接种的方法,对烟草种质资源的马铃薯Y病毒（Potato virus Y,PVY）抗病性进行鉴定;通过烟草隐性抗PVY基因eIF4E1（又称为感PVY基因eIF4E1）等位性测验、等位基因分子标记检测和RT-PCR扩增测序,对PVY抗病资源进行基因型分析。  结果  （1）从收集到的900多份来自国内外的烟草种质资源中筛选出19份高抗PVY资源。（2）根据等位性测验结果推断19份抗源所具有的PVY抗性均由eIF4E1基因所控制。（3）等位基因分子标记检测和RT-PCR扩增测序结果将19份抗源的eIF4E1基因区分为4种突变类型。  结论  本研究结果丰富了我国对抗PVY烟草种质资源的筛选和利用的内容,为后续烟草PVY抗性优异等位基因的发掘和育种利用提供了基础材料和信息支撑。      

Proteomic assessment of resistance to the fumigant phosphine in the lesser grain borer, Rhyzopertha dominica (F.)

A previous publication compared a strain of the stored-grain pest beetle, Rhyzopertha dominica, resistant to the fumigant phosphine, with a susceptible strain using two-dimensional polyacrylamide gel electrophoresis. Certain proteins appeared to differ and the authors proposed that arginine kinase in particular might be used as a marker for the rapid monitoring of resistance in this species and other pests of stored grain. Here an expanded set of susceptible and resistant strains is surveyed using the two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) system. Of hundreds of spots only two showed a significant difference between the resistant and susceptible strains and the magnitudes of those differences were less than three-fold. Arginine kinase spots were identified but they did not differ significantly. The proposal that certain abundant proteins of R. dominica might be used as markers of phosphine resistance was not supported by the present study.     

Mattesia trogodermae infection rates as influenced by mode of transmission, dosage and host species

Specificity of infection by Mattesia trogodermae Canning was tested on six species of Trogoderma. Exposure of insects to similar numbers of spores indicated infections are always fatal in T. sternale Jayne, T. simplex Jayne, T. glabrum (Herbst) and T. inclusum LeConte. Rates of mortality (LT₅₀'s) were similar among the susceptible species and infection always reached 100 per cent in exposed insects. Trogoderma grassmani Beal and T. variabile Ballion were not infected at the dosages studied.

When eggs were seeded on to medium containing spores, the number of adults produced from such cultures was reduced by 50 per cent with an inoculation rate of 50 spores/g medium. Five thousand spores/g were necessary to infect all larvae before reaching the adult stage, however, this effect could be achieved with fewer total spores per jar if they were concentrated in the upper 1/5 of medium in the culture container. Infected larvar, when introduced into cultures, also cause infection of newly hatched larvae and subsequent reduction of adult production. A single infected larva reduced adult production by 25 per cent; 100 per cent infection of larvae was effected with 25–50 infected larvae per 50 g medium.

Adult T. glabrum males externally contaminated with Mattesia were able to transmit infective spores to females. Spore presence on the adults was determined by feeding the freeze-killed insects to larvae and inspecting the larvae for infection several weeks later. Male beetles were initially contaminated by being drawn to a corrugated cardboard inoculation device treated with pheromone ((Z)-14-methyl-8-hexadecen-1-ol) and dusted with Mattesia powder. Pheromone-baited inoculation devices resulted in contamination of 96 per cent of test insects placed in the arena whereas only 56 per cent picked up spores from inoculation devices containing only Mattesia spores (no pheromone).     

Resistance to aflatoxin accumulation in kernels of maize inbreds selected for ear rot resistance in West and Central Africa

Thirty-six inbred lines selected in West and Central Africa for moderate to high resistance to maize ear rot under conditions of severe natural infection were screened for resistance to aflatoxin contamination using the previously established kernel screening assay. Results showed that more than half the inbreds accumulated aflatoxins at levels as low as or lower than the resistant U.S. lines GT-MAS:gk or MI82. In 10 selected aflatoxin-resistant or aflatoxin-susceptible inbreds, Aspergillus flavus growth, which was quantified using an A. flavus transformant containing a GUS-beta-tubulin reporter gene construct, was, in general, positively related to aflatoxin accumulation. However, one aflatoxin-resistant inbred supported a relatively high level of fungal infection, whereas two susceptibles supported relatively low fungal infection. When kernels of the 10 tested lines were profiled for proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, significant variations from protein profiles of U.S. lines were observed. Confirmation of resistance in promising African lines in field trials may significantly broaden the resistant germplasm base available for managing aflatoxin contamination through breeding approaches. Biochemical resistance markers different from those being identified and characterized in U.S. genotypes, such as ones inhibitory to aflatoxin biosynthesis rather than to fungal infection, may also be identified in African lines. These discoveries could significantly enhance the host resistance strategy of pyramiding different traits into agronomically useful maize germplasm to control aflatoxin contamination.     

The characterisation of Bacillus spores occurring in the manufacturing of (low acid) canned products

Spore-forming bacteria can be a problem in the food industry, especially in the canning industry. Spores present in ingredients or present in the processing environment severely challenge the preservation process since their thermal resistance may be very high. We therefore asked the question which bacterial spore formers are found in a typical soup manufacturing plant, where they originate from and what the thermal resistance of their spores is. To answer these questions molecular techniques for bacterial species and strain identification were used as well as a protocol for the assessment of spore heat stress resistance based on the Kooiman method. The data indicate the existence and physiological cause of the high thermal resistance of spores of many of the occurring species. In particular it shows that ingredients used in soup manufacturing are a rich source of high thermal resistant spores and that sporulation in the presence of ingredients rich in divalent metal ions exerts a strong influence on spore heat resistance. It was also indicated that Bacillus spores may well be able to germinate and resporulate during manufacturing i.e. through growth and sporulation in line. Both these spores and those originating from the ingredients were able to survive certain thermal processing settings. Species identity was confirmed using fatty acid analysis, 16SrRNA gene sequencing and DNA-DNA hybridisation. Finally, molecular typing experiments using Ribotyping and AFLP analysis show that strains within the various Bacillus species can be clustered according to the thermal resistance properties of their spores. AFLP performed slightly better than Ribotyping. The data proofed to be useful for the generation of strain specific probes. Protocols to validate these probes in routine identification and innovation aimed at tailor made heat processing in soup manufacturing have been formulated.     

烟草PVY隐性抗病基因的分子标记及其适用性

马铃薯Y 病毒(Potato virus Y,PVY)是危害烟草的重要病害, 种植抗病品种是经济有效的防治措施。分子标记辅助选择可提高抗病育种效率。来源于X-射线诱变的Virgin A Mutante(VAM) 的隐性抗PVY 基因位点(va)被广泛应用于烟草抗病育种。为了提高va 位点的育种利用效率, 根据烟草隐性抗PVY 基因(感病基因)eIF4E-1 基因序列, 设计特异扩增的引物CF2GR11,开发eIF4E-1 基因的分子标记, 并检测了该标记与抗性的遗传距离和在常见烟草资源中的适用性。CF2GR11 在云烟87、红花大金元和K326 等感PVY 品种可扩增出500 bp 产物, 在NC102、NC55 和K326PVY 等抗病品种无扩增条带。以抗、感PVY 亲本构建的101 个F₂ 单株为定位群体, 遗传连锁分析表明, CF2GR11 标记与烟草PVY 感病基因的遗传距离为0.99 cM。对46 份PVY 抗性明确的栽培烟草资源的检测表明, 供试资源的标记检测结果与抗性的吻合度为100%, 表明CF2GR11 标记适用性高。该目的基因标记可用于抗PVY 育种的辅助选择和抗PVY 资源的鉴定。      

Factors Influencing Radiation Resistance of Vegetative Bacteria and Spores Associated with Radappertization of Meat

The influence of some factors involved in radappertization of meats on the radiation resistance of two isolates of Moraxella-Acinetobacter (M-A), Microcodes radiodurans, Escherichia coli, and Bacillus cereus spores was determined. Combinaton of subfreezing temperature and lyophilization increased the resistance of vegetative cells and showed M-A isolates to be most resistant. Cells lyophilized in ground beef were less resistant than cells lyophilized in a commercial culture medium. A preirradiation heat treatment prior to lyophilization sensitized the cells to radiation. No appreciable difference in resistance was found with the presence of up to 8% sodium chloride during irradiation of M-A and M. radiodurans. The radiation resistance of B. cereus spores was not affected by changes in temperature, drying, or suspending medium to the same extent as were the vegetative cells. B. cereus spores were more resistant at ambient temperature than at -30 ± 10°C. All these factors must be considered in assessing the magnitude of radiation resistance of various organisms, be cause there is no predictable pattern of radiation resistance.     

香蕉果实采后诱导抗病性的初步研究

本文比较了热处理、水杨酸处理、冷处理和UV-C处理诱导香蕉果实采后抗病性的效果。结果表明,接种炭疽病菌孢子10d后,发现热处理(53℃热水浸泡10min)可明显控制香蕉果实病斑的扩展,延缓了果实的后熟软化和褪绿转黄。热处理诱导抗病性的效果与接种时间及香蕉采收日期有关。水杨酸处理(1mmol/L)对诱导香蕉果实抗病性也有一定的效果,而冷击处理促进了病害的发展、促进了后熟软化和褪绿转黄。UV-C处理(160～320s)虽然可延缓香蕉果的软化,但果皮病斑增大,色泽变褐。