不同寄主植物对美国白蛾肠道细菌群落的影响

为明确美国白蛾Hyphantria cunea在取食不同寄主植物后其肠道细菌群落的变化情况,采用高通量测序技术分析其肠道细菌16S rDNA的V3～V4区域,分析肠道细菌的多样性、物种组成和菌群结构差异,并对其生物学功能进行预测。结果显示,美国白蛾4龄幼虫在取食不同寄主植物后肠道细菌Shannon多样性指数出现明显差异,由高到低依次为取食寄主法国梧桐Platanus orientalis、柿Diospyros kaki、胡桃Juglans regia、杨树Populus×canadensis和杏Armeniaca vulgaris的群体。美国白蛾肠道优势菌门主要为变形菌门和厚壁菌门,而属分类水平上的物种在不同处理之间存在较大差异,在取食法国梧桐和柿树的美国白蛾肠道中Burkholderia-Caballeronia-Paraburkholderia的相对丰度较高,分别为63.16%和34.50%;取食杏树和杨树的美国白蛾肠道优势菌属分别是肠球菌属Enterococcus和肠杆菌属Enterobacter,相对丰度分别为87.58%和37.93%。不同寄主也导致美国白蛾肠道细菌群的组成结...     

麦二叉蚜传播玉米矮花叶病毒的机制

用胶体金标记法和荧光抗体标记法研究了麦二叉蚜(Schizaphis graminum)传播玉米矮花叶病毒(Maize dwaft mosaic virus,MDMV)的机制。麦二叉蚜传播玉米矮花叶病毒需要辅助成份-蛋白酶(Helper component-proteinase,HC-Pro)的参与。在电镜下观察到HC-Pro可以与MDMV粒子结合。用FITC标记的HC-Pro抗体和MDMV抗体证明,HC-Pro可以直接结合到蚜虫口针上;而MDMV粒子不能直接结合到蚜虫口针,必须在HC-Pro的辅助下才能结合到蚜虫口针上。这为HC-Pro在蚜虫传毒过程中起桥梁作用提供了新的证据。MDMV粒子主要吸附在蚜虫口针的尖端和中间部分。     

我国小麦产区间病害发生与损失差异比较研究

为系统全面地掌握我国各产区小麦病害的发生情况,本文重点分析了我国小麦五大产区(华东麦区、华中麦区、华北麦区、西北麦区和西南麦区)小麦锈病、赤霉病、白粉病、纹枯病、黑穗病、根腐病和全蚀病的发生及防控情况。结果表明：我国小麦病害发生危害具有区域性特点,华东和华中麦区小麦纹枯病和赤霉病发病面积较大,且造成产量损失占比远超其余三大产区;华北麦区以白粉病发生最重;西北和西南麦区锈病和白粉病发生最重。我国小麦病害防治效果显著,华东和华中麦区赤霉病、纹枯病的年均挽回损失率均在80%以上;华北麦区年均挽回损失率最高的病害是白粉病(84.43%);西北和西南麦区对锈病年均挽回损失率分别为78.20%和85.26%;黑穗病、根腐病和全蚀病挽回损失率较低。     

荒漠植物红砂(Reaumuria soongorica)的保育效应及其对群落物种多样性的影响

红砂(Reaumuria soongorica)是我国北方温带荒漠的主要先锋植物,也是一种潜力巨大的水土保持和荒山绿化物种,但是该乡土物种是否具有保育植物的特征,目前尚未有这方面的研究。文中通过研究生长于半干旱区的荒漠植物红砂群落不同分布格局和群落特征,分析红砂盖度变化对群落多样性的影响,探究保育效应的发生条件及其对群落物种多样性影响机理。研究结果表明:群落的植物物种多样性随着红砂植被盖度和地上生物量增大而逐渐增大,然而,当红砂总盖度超过48.73%(地上生物量为35.62g/m2)时,虽植被盖度和地上生物量继续增大,目标物种碱蓬(Suaeda glauca),蓍状亚菊(Ajania achilleoides)多度明显增加,但植物物种多样性并没有显著的变化。这些说明在干旱区,当红砂的盖度增加到一定程度之后,才能通过冠层遮阴产生保育效应。因此,在植被稀疏、物种多样性较低的干旱地区,可以充分利用红砂物种的保育效应,促进和加快植被自然恢复进程,调控物种多样性和群落结构。     

Challenges facing arthropod biological control: identifying traits for genetic improvement of predators in protected crops

Biological control is an efficient pest control method but there are still limitations that are hindering its wider adoption. Genetic improvement of biological control agents (BCAs) can help to overcome these constraints, but the choice of key attributes for better performance that need to be selected is still an open question. Several characteristics have been suggested but the harsh reality is that selective breeding of BCAs has received a lot of attention but resulted in very little progress. Identifying the appropriate traits to be prioritized may be the first step to reverse this situation. In our opinion, the best way is to look at the factors limiting the performance of key BCAs, especially generalist predators (pesticide compatibility, prey‐density dependence, non‐suitable crops, and extreme environmental conditions), and according to these challenges, to choose the attributes that would allow BCAs to overcome those limitations. The benefits of selection for higher resistance to toxins, whether artificially applied (pesticides) or plant produced (plant defenses); increased fitness when feeding on non‐prey food (supplemented or plant‐derived); and better adaptation to extreme temperature and humidity are discussed. In conclusion, genetic improvement of BCAs can bring about new opportunities to biocontrol industry and users to enhance biocontrol resilience. © 2020 Society of Chemical Industry     

有害生物风险分析定量评估模型及其比较

全球化的进程使有害生物入侵问题日益严重,植物检疫工作备受重视。有害生物风险分析(pest risk analysis,PRA)是植物检疫的支撑技术之一,风险评估是其核心内容,定量评估模型的研究与应用成为近30年来该领域的热点。本文在收集、整理国内外PRA文献和相关信息的基础上,针对有害生物入侵风险半定量评估模型、定量评估模型及软件的发展进行了系统性的回顾和分析。同时,我们比较了主要模型和软件的特点、优势和局限性,归纳总结出了适用于不同起点的有害生物定量风险评估集成技术体系,并展望了我国有害生物风险分析技术的未来发展。本综述能够为我国生物入侵防控管理机构、推广部门、高等院校及科研单位提供重要的工作参考,对植物检疫工作具有理论和实践意义。     

一种快速简便的植物病原真菌基因组DNA提取方法

 尿素提取法是最新报道的一种植物拟南芥基因组DNA的提取方法,但是还没有应用于植物病原真菌DNA的提取。本研究采用改进的4种不同的方法(尿素提取法、CTAB提取法、氯化苄提取法以及SDS-CTAB提取法),分别对5种分类地位不同的植物病原真菌(草莓疫霉病菌、西瓜蔓枯病菌、草莓炭疽病菌、西瓜枯萎病菌和水稻纹枯病菌)的基因组DNA进行提取和比较。结果表明,尿素提取法和SDS-CTAB法均能提取到所有5种真菌的基因组DNA,而尿素提取法提取DNA的效率更高、质量更好,操作步骤更为快速简单。     

植物提取物、碳酸钠和碳酸氢钠室内对杨树溃疡病菌生长的抑制作用

 采用菌丝生长速率法用金银花的花、黄花蒿的地上部分、蓝桉果实和黄柏果实的乙醇提取物及其不同极性的组分对杨树溃疡病菌菌丝生长的抑制作用进行了测定。以黄柏果实的抗菌活性最强,其次是金银花的花。抗菌活性成分主要存在于金银花的正丁醇组分、黄花蒿的石油醚组分和乙酸乙酯组分、蓝桉的水部分、黄柏的正丁醇组分。当培养基中碳酸钠和碳酸氢钠的浓度分别为8g/L时(对应的pH值分别为10.24和7.71),菌丝生长抑制率分别为100.00%和79.68%。如果用1mol/L氢氧化钠溶液调节培养基的pH值至10.00,菌丝生长抑制率为40.58%。说明碳酸钠或碳酸氢钠对菌丝生长的抑制作用,一方面是由于改变了培养基的pH值,另一方面可能是由于碳酸根和碳酸氢根离子抑制了菌丝的生长。     

药用植物提取物对草莓灰霉病菌抑菌活性研究

用丙酮为溶剂提取7种药用植物材料粉末,得到提取物母液。采用生长速率法和叶片离体接菌法测试提取物对草莓灰霉病菌的室内抑菌作用。在供试的7种植物材料中,五味子对菌丝生长的抑制率最高,达到95.65%,其次为薏苡,抑菌率为91.30%,决明、酸浆的抑菌率均达到了85%以上。结合叶片离体接菌法的试验结果,认为五味子和酸浆可以作为重点进行深入研究。     

Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce

High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R² = 0.87) and with black background (R² = 0.95), juvenile plants (R² = 0.94), and top views and side views of entire tree crowns of adult trees (R² = 0.98 and 0.88, respectively). Results underline that a well‐defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time‐efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.