Efficacy of mineral oil combined with insecticides for the control of aphid virus vectors to reduce potato virus Y infections in seed potatoes (Solanum tuberosum)

Abstract

Aphids are major vectors of plant viruses. Potato virus Y (PVY) is the most important aphid-transmitted virus affecting potato crops in Denmark. Because of a changed seed potato growing strategy, the seed potato area in Denmark is changing from regions with a low average temperature to regions with a higher average temperature. This means that the aphids may infest the potato crops earlier and the population development of the aphids may be faster, and consequently PVY may more easily become epidemic in seed potato crops. With a view to reducing the spread of PVY a 3-year experiment was carried out with a combination of mineral oil and insecticides.

In 2005 and 2007 when a very high number of aphids were present, nearly all plants were infected with PVY. In 2006 with a lower number of aphids a smaller proportion of the plants were infected, and a tendency to a lower PVY incidence in mineral-oil treated plots was found, but more than the 8% threshold value. Even in plots where systemic neonicotinoids were applied and very few aphids were recorded, no significant reduction in infestation level of PVY was found.

The present experiment shows that mineral oil and insecticides applied to potato crops each week for a 6-week period as protection against aphid transmission of PVY did not significantly reduce the level of PVY infestations in potatoes.     

烟草马铃薯Y病毒病相关基因eIF4E的片段克隆及RNAi载体构建

以感病烟草品种为材料,提取总RNA,根据已报道的eIF4E基因cDNA的序列,在保守区域和差异区域分别设计特异性引物,采用RT-PCR克隆出eIF4E基因的目的片段。以中间载体pKANNIBAL和表达载体pART27为基础,构建成以CaMV35S启动子为驱动的含有“正向eIF4E目的片段-pdk intron-反向eIF4E目的片段”的RNAi烟草表达载体,构建的RNAi载体将抑制eIF4E基因表达,为了解其基因功能和烟草抗病毒育种打下基础。     

高温激活RNA沉默介导的心叶烟抗病毒防御反应

 在真核细胞内,RNA沉默是一种保守的抵抗病毒及外源基因等寄生分子的防御机制。温度可以明显地影响植物体与病毒之间的相互作用。在常温状态下,常常会伴随病毒病的爆发,但在较高温度下,症状则会减轻,甚至有些感病植株新生叶片可以较快地恢复健康。目前这类现象的内在机制还不完全清楚。本文通过定量分析不同温度下马铃薯X病毒(Potato virus X,PVX)和马铃薯Y病毒(Potato virus Y,PVY)侵染的心叶烟(Nicotiana glutinosa)植株体内病毒蛋白含量,结合症状观察,确定30℃左右是PVX和PVY在心叶烟上引起症状消失即发生系统性RNA沉默的临界温度,此时的感病植株上部新生展开叶片呈现无症状态,下部已发病叶片症状不变。在常温时,由病毒激发的RNA沉默会受到抑制,病毒来源的小分子干涉RNA (small interfering RNAs,siRNAs)含量极少或根本检测不到,植株对于病毒的敏感性较强。当温度达到30或32℃时,感病植株下部症状保持叶片中,病毒起源的siRNAs含量明显增加,而上部新生健康叶片中却检测不到siRNAs的存在。这说明高温激活了RNA沉默介导的植物抗病毒防御反应,导致病毒症状减轻甚至消失。     

Potato Virus Y from Petunia can cause Symptoms of Potato Tuber Necrotic Ringspot Disease (PTNRD)

A potyvirus known to be an important agent involved in causing a disease of trailing petunias, was identified as being a member of the necrotic strain of potato virus Y (PVY) using a number of monoclonal antibodies. The sequence of the coat protein gene for the PVY isolate was determined and when compared with sequences for other PVY strains it was shown to cluster closely with isolates of PVY^NTN and to have a recombination point present within the coat protein common with other isolates of PVY^NTN. When inoculated onto potato tuber necrotic ringspot disease (PTNRD) susceptible potato cultivars the petunia isolate was found to be capable of causing necrotic tuber symptoms, consistent with those caused by other isolates of PVY^NTN. Due to the number of similarities it is thought the petunia isolate belongs to the PVY^NTN group of isolates. Out of 24 species of bedding and pot plant crops tested, 19 were shown by mechanical inoculation to be susceptible to PVY, highlighting not only a clear risk to a number of commercially important plant species from PVY^NTN infected trailing petunias, but also other susceptible crops grown in these areas.     

马铃薯六种主要病毒通用RT-PCR检测体系的建立

马铃薯X病毒(PVX)、马铃薯Y病毒(PVY)、马铃薯S病毒(PVS)、马铃薯卷叶病毒(PLRV)、马铃薯M病毒(PVM)和马铃薯A病毒(PVA)是马铃薯生产田中发生率较高、危害较严重的病毒,因此,建立特异性强、灵敏度高、检测速度快的RT-PCR分子检测体系对保障马铃薯种薯质量具有非常重要的意义。试验筛选了6种病毒的特异引物、优化了PCR部分的试剂以及确定了退火温度。结果表明,当Mg2+浓度为2.6 mmol/L、d NTPs浓度为0.1 mmol/L、Taq DNA聚合酶浓度为0.03 U/μL,以及退火温度为55.5℃时反应体系最稳定。最终,建立了一套通用RT-PCR检测体系,只需要变换每种病毒的引物,就可以实现对PVX、PVY、PVS、PLRV、PVM和PVA病毒的RT-PCR检测。每种病毒检测灵敏度均能达到pg以上。     

Prevention of virus epidemics by a crop-free period in the arava region of Israel

In the isolated Arava region of Israel, virus epidemics in vegetables were avoided by enforcing a crop-free period of one month during June-July. It was found that the cultivated crops are the major reservoir of viruses, and that during these months the insect vector population and the natural virus sources are low. Therefore, a one-month crop-free period was declared during June-July, and since its enforcement in 1986, no economic damage caused by insect-borne viruses has been recorded. Contribution from the Agricultural Research Organization. No. 2323-E, 1997 series     

马铃薯Y病毒一步RT-PCR检测试剂盒的研制

马铃薯Y病毒(Potato virus Y,PVY)对马铃薯的危害最大,可导致马铃薯退化,降低马铃薯产量。解决这一问题的重要途径就是培养脱毒种薯,但是否完全脱毒需要经过检测才能证实。本研究依据PVY CP基因序列设计合成了一对引物PY1、PY2,以带毒样品植物总RNA为模板,在同一个反应中同时加入反转录和PCR反应所需试剂,反应程序中包括反转录和PCR反应所需条件,进行反应扩增,带毒样品扩增得到340 bp的目的条带,而健康对照无此目的条带,从而建立了PVY的一步RT-PCR检测技术,并组装成试剂盒。该试剂盒具有良好的稳定性和特异性,灵敏度可以检测到带毒植物组织下限的6.25μg,高于ELISA(100μg)和NASH(15μg)的灵敏度,虽然和常规方法的灵敏度相同,但更为快速、简便、易于操作,适合脱毒苗和脱毒种薯生产单位做大量样品的检测。     

烤烟不同栽培模式对马铃薯Y病毒病发病率的影响

在贵州省瓮安县烟草马铃薯Y病毒病(PVY)重病区,对露地烟、双行麦套烟、单行麦套烟、单行白膜烟、双行黑膜烟、单行银膜烟、单行葱套烟7种栽培模式烟草的PVY发病情况进行了调查,旨为明确不同烤烟栽培模式对烟草PVY发病率的影响。结果表明:7种栽培模式烟草的PVY平均病株率顺序为单行麦套烟(4.1%)<单行银膜烟(6.1%)<单行葱套烟(8.1%)<双行麦套烟(17.3%)<单行白膜烟(23.5%)<露地烟(42.3%)<双行黑膜烟(50.1%),单行麦套烟、单行银膜烟和单行葱套烟的平均病株率明显较低。在瓮安县烟草马铃薯Y病毒病重病区,建议推广单行麦套烟栽培模式。     

烟草马铃薯Y病毒病的生物防治研究进展

马铃薯Y病毒病在我国分布范围广、危害重,严重影响着烟草的产量和质量。目前大部分烟区仍使用化学农药来防治烟草马铃薯Y病毒病,导致烟叶中农药的残留量增加,不符合农业的可持续发展,危及人类健康,破坏生态平衡。综述了烟草马铃薯Y病毒病的病原、发病条件和发病症状,以及该病的发病因素和生物防治方法,并对利用生物方法防治烟草马铃薯Y病毒病的前景进行了展望。     

Representation of Potato Virus Y Control Strategies in Current and Past Extension Literature

The aphid-vectored Potato virus Y (PVY) is currently seen as an important limiting factor in the production of potatoes in many countries. Using a content-analysis approach, we investigated the German extension literature for recommendations regarding the control of PVY. Media included articles from periodicals addressing farmers and agricultural textbooks published in the last five decades (1955–2004). In the current literature (1995–2004), the clearly dominating strategy was found to be insecticidal control, although this strategy has been subject to some criticism in the scientific literature. Over the last five decades we also found a strongly increasing representation of insecticidal strategies. Furthermore, over this period of time, information diversity, measured as the number of different strategies proposed per article or per textbook, decreased consistently. Electronic supplementary material The online version of this article () contains supplementary material that is available to authorized users.