Variety,mulch and stage of inoculation effects on incidence of tomato spotted wilt virus disease in cucumber (Cucumis sativus L.)

Abstract

Tomato spotted wilt virus (TSWV) vectored by thrips is one of the major diseases affecting cucumber yield. Control of thrips is an underlying factor in its management. A study was conducted to determine the effect of time of inoculation, variety and mulch on disease incidence. Four varieties were inoculated with TSWV at cotyledon, 3 – 4 leaf and flower bud stages in a RCBD experiment replicated four times in a greenhouse. In the field, a 2×8 factorial design where two cucumber varieties were raised on seven types of mulches (red, yellow, silver, clear, black, white, and straw) with unmulched plots as controls was used. Variety Marketer was more tolerant to the disease compared to other varieties. Most varieties were generally tolerant to TSWV at cotyledonous but susceptible at 3 – 4 leaf and flower bud stages. Silver and clear mulches significantly suppressed thrip populations, yield and quality under field conditions.     

接种番茄斑萎病毒番茄植株对西花蓟马生物学特性的影响

西花蓟马Frankliniella occidentalis(Pergande)是我国的一种重要入侵害虫。本文研究了西花蓟马在番茄3种处理(健康CK、机械接种番茄斑萎病毒MI、机械损伤MD)叶片上的生长发育、存活及种群增长。结果表明:健康、机械接种番茄斑萎病毒、机械损伤叶片上的发育历期依次为12.68、12.99和11.79d。雌雄成虫寿命和雌虫繁殖能力在各处理叶片上差异不显著(P>0.05)。健康、机械接种番茄斑萎病毒、机械损伤叶片上的内禀增长率依次为0.1362、0.1526和0.1292d-1。本研究表明,接种番茄斑萎病毒的番茄叶片未缩短西花蓟马发育历期,也不能延长寿命及提高产卵量,不能明显加速种群数量增长。这意味着番茄斑萎病毒对西花蓟马在番茄叶片上的生物学特性未能产生明显的有利作用。     

番茄斑萎病毒对多杀菌素抗性西花蓟马发育繁殖和药剂敏感性的影响

【目的】西花蓟马Frankliniella occidentalis (Pergande)是重要的入侵害虫,是番茄斑萎病毒（TSWV）最有效的传播媒介,TSWV对西花蓟马的生长发育有一定的影响。多杀菌素是防治西花蓟马最有效的药剂之一,但已有田间西花蓟马对多杀菌素产生抗药性的报道。TSWV对抗性西花蓟马是否也有影响及程度如何尚不清楚。本研究通过对此问题进行深入研究,以期为进一步了解TSWV对西花蓟马的影响提供依据。【方法】应用特定年龄-龄期及两性生命表的方法,研究用番茄斑萎病毒处理和未处理的多杀菌素抗性和敏感西花蓟马种群的生物学特性;用叶管药膜法测定不同处理种群对3种药剂（多杀菌素、甲氨基阿维菌素苯甲酸盐和虫螨腈）的敏感性变化。【结果】对于抗性品系,TSWV处理后西花蓟马的发育历期缩短,雌成虫寿命和产卵量略高,但与对照组差异不显著(P＞0.05),内禀增长率（r）和净生殖率（R₀）分别为0.0433 d^-1和2.210,显著高于对照组（分别为0.0356 d^-1和1.972）（P ≤ 0.001）。对于敏感品系,TSWV处理后西花蓟马的发育历期缩短,雌雄成虫寿命均显著延长（P ≤ 0.001）,产卵量也略有提高,R₀为4.125,显著高于对照组（3.979）（P ≤ 0.001）。TSWV处理后敏感和抗性西花蓟马对多杀菌素的敏感性没有发生明显变化,对甲氨基阿维菌素苯甲酸盐和虫螨腈的敏感性显著降低。【结论】番茄斑萎病毒对多杀菌素敏感和抗性西花蓟马均有直接有利影响,病毒处理的西花蓟马发育历期缩短,繁殖能力增强,成虫寿命延长,对药剂的敏感性降低。     

Влнянне характера эаселення ноля капустноii совкоii(Barathra brassicae L.) эффективноеть трихограммы (Trichogramma evanescens Westw.) (Lepidoptera,Noctuidae; Hymenoptera,Trichogrammatidae)

TSWV belongs to the genus Tospovirus which was established in the family Bunyaviridae, a family of animal viruses. Besides TSWV, Impatiens necrotic spot virus (INSV) and ground nut bud necrosis virus (GBNV) were established as different Tospovirus species. Tospoviruses have quasispherical particles of 85 nm diametre which are surrounded by a membrane and contain 3 RNA species and 4 structural proteins. In Tospovirus infected plant cells virions were detected in cavaties of the endoplasmatic reticulum and additionally amorphous electron dense material accumulates in infected cells. Defective forms of TSWV lack the ability to form complete virus particles. TSWV is the only plant pathogenic virus that is transmitted by thrips which transmit the virus with different efficiency. The virus has an extensive plant host range of more than 360 different species. The developing symptoms depend on the Tospovirus species, the virulence of the virus strains and the environmental conditions.

Based on the reaction of TSWV isolates with N‐specific polyclonal antisera, 3 serogroups were established. The most frequently used technique for serologically based diagnosis of Tospoviruses is DAS ELISA with N‐specific or preadsorbed antisera against complete virus. For TSWV epidemiology distinct weeds and cultural host plants play an important role for the survival of virus and vector. Breeding for resistance is the most important preventive measure of control.     

我国南方花生发生一种由蕃茄斑萎病毒引起的新病害

我们于1984和1985年6月上、中旬,在广州市郊、县,湛江市郊以及广西南宁市郊、县,北海市郊和合蒲县等花生产区,调查花生病毒病时,除了发现花生轻斑驳病毒病外,还发现一种新的病毒病害。其症状特征是:病株顶端叶片上出现很多褪绿黄斑或环斑,有的环斑变     

Herbivore benefits from vectoring plant virus through reduction of period of vulnerability to predation

Herbivores can profit from vectoring plant pathogens because the induced defence of plants against pathogens sometimes interferes with the induced defence of plants against herbivores. Plants can also defend themselves indirectly by the action of the natural enemies of the herbivores. It is unknown whether the defence against pathogens induced in the plant also interferes with the indirect defence against herbivores mediated via the third trophic level. We previously showed that infection of plants with Tomato spotted wilt virus (TSWV) increased the developmental rate of and juvenile survival of its vector, the thrips Frankliniella occidentalis. Here, we present the results of a study on the effects of TSWV infections of plants on the effectiveness of three species of natural enemies of F. occidentalis: the predatory mites Neoseiulus cucumeris and Iphiseius degenerans, and the predatory bug Orius laevigatus. The growth rate of thrips larvae was positively affected by the presence of virus in the host plant. Because large larvae are invulnerable to predation by the two species of predatory mites, this resulted in a shorter period of vulnerability to predation for thrips that developed on plants with virus than thrips developing on uninfected plants (4.4 vs. 7.9 days, respectively). Because large thrips larvae are not invulnerable to predation by the predatory bug Orius laevigatus, infection of the plant did not affect the predation risk of thrips larvae from this predator. This is the first demonstration of a negative effect of a plant pathogen on the predation risk of its vector.     

寄主植物接种番茄斑萎病毒对西花蓟马种群的影响

【目的】西花蓟马Frankliniella occidentalis (Pergande)是一种入侵我国的重要害虫, 而番茄斑萎病毒是以西花蓟马传播为主的一种极具危害性的世界性病毒, 通过研究西花蓟马与番茄斑萎病毒之间的互作将有助于进一步深入理解西花蓟马以及番茄斑萎病毒的发生与猖獗机制, 同时也将为制定合理、可持续的控制西花蓟马及其传播的植物病毒防控策略提供理论依据。【方法】利用应用特定年龄-龄期及两性生命表方法, 研究了西花蓟马在辣椒3种处理（健康CK、机械损伤MD、机械接种番茄斑萎病毒MI）叶片上的生长发育、存活及种群增长。【结果】健康、机械损伤和机械接毒叶片上的发育历期依次为12.45, 11.97和11.18 d。雌雄成虫寿命和雌虫产卵量在不同处理植株叶片上差异显著(P<0.05), 在机械接毒叶片上寿命最长(雌13.51 d, 雄12.69 d); 繁殖能力最强, 产子代数高达33.01头1龄若虫/雌。健康、机械损伤和机械接毒叶片上西花蓟马内禀增长率分别为-0.009, 0.153和0.190 d-1, 净生殖率依次为0.84, 14.54和21.79。【结论】番茄斑萎病毒诱导寄主植物辣椒反应使西花蓟马发育历期缩短, 成虫寿命延长, 繁殖能力提高, 种群增长加速。     

以番茄斑萎病毒核蛋白为靶点的荧光偏振药物筛选体系的建立及应用

目的:基于荧光偏振技术建立靶向番茄斑萎病毒(Tomato spotted wilt virus,TSWV)核蛋白(NP)与核酸相互作用的药物筛选体系,并应用该体系展开药物筛选。方法:将目的基因克隆到pGEX-6p-1表达载体上,并采用大肠杆菌表达系统进行目的蛋白的异源表达。建立靶向TSWV NP与核酸相互作用的荧光偏振药物筛选体系,对体系的结合时间、DMSO耐受、变异性和稳定性进行研究,并展开药物筛选。结果:成功构建重组质粒pGEX-6p-1-NP,在大肠杆菌中表达并分离纯化出高质量的核蛋白。基于荧光偏振技术建立了信噪比为8∶1,Z因子为0. 82的稳定的靶向TSWV NP与核酸相互作用的药物筛选体系,并对化合物库中1 000种化合物展开药物筛选,经过初步筛选获得了1种IC_(50)为4. 15μmol/L的化合物。结论:建立了稳定的荧光偏振筛选体系,适用于靶向NP与核酸相互作用的药物的筛选。筛选到的化合物为番茄斑萎病毒的预防和控制提供参考。     

A multi-generation analysis of the stability of transgenic virus resistance in doubled-haploid tobacco lines

Plants can be genetically engineered for virus resistance by transformation with a viral gene. We transformed tobacco with the tomato spotted wilt virus (TSWV) nucleocapsid gene from the Hawaiian L isolate in order to obtain TSWV resistant breeding lines. Doubled-haploid lines were produced from primary transgenic plants that were selected for resistance to the virus. Several of these lines showed very high levels of resistance and were symptomless after inoculation with the Hawaiian L isolate of TSWV. The accumulation of only low levels of full-length transgene RNA and protein observed in these lines is consistent with an RNA-mediated mechanism of resistance. The lines that were highly resistant to the Hawaiian L isolate of TSWV were also found to be highly resistant to several other isolates of TSWV, while lines that were only moderately resistant to the Hawaiian L isolate were often susceptible to the other isolates. The highly resistant lines were advanced over several generations by self-pollination. Although these lines were fully homozygous, several lines lost resistance in later generations, indicating that the resistance was unstable. Selection for resistance in these unstable lines did not prevent the occurrence of susceptible progeny in subsequent generations. Therefore, testing over several generations is required to determine the stability of resistance when breeding crops with transgenic virus resistance.     

西花蓟马的抗药性及其治理策略

西花蓟马Frankliniella occidentalis（Pergande）是世界性的园艺作物上的重要害虫,几乎对每种类型的杀虫剂均产生了抗药性,包括有机磷、氨基甲酸酯、拟除虫菊酯类杀虫剂和多杀菌素等。本文对国外西花蓟马的抗药性发展现状和抗性机制进行了总结,并提出了抗性治理策略,即科学合理使用杀虫剂,结合栽培防治、物理防治、生物防治和寄主植物抗性等方式降低杀虫剂对西花蓟马的选择压,从而达到抗性治理的目的。     

北京地区西花蓟马田间种群的抗药性监测

采用叶管药膜法在室内测定了2009—2010年北京海淀地区和昌平地区西花蓟马Frankliniella occidentalis(Pergande)田间种群对12种杀虫剂敏感性的年度变化。结果表明,北京昌平和海淀地区的西花蓟马对多数的药剂仍处于敏感状态,但对氯氟氰菊酯已产生近40倍的抗性,昌平种群对多杀菌素具有产生低水平抗性的趋势(抗性倍数为4倍)。推荐药剂包括多杀菌素、阿维菌素、甲氨基阿维菌素苯甲酸盐(甲维盐)、毒死蜱和溴虫腈,应注意与其它药剂的轮换使用,灭多威对西花蓟马的毒力水平最低,不推荐使用。