Herbicide‐resistant genetically‐modified crop: its risks with an emphasis on gene flow

Herbicide‐resistant genetically‐modified (GM) crops are the most widely cultivated worldwide, representing 78% of GM crops in 1999, followed by insect‐resistant GM crops with Bt gene. Gene flow is the most touching risk arising from GM crops, and is categorized as three types: within species, between species and between GM crop and other organisms. This review shows that gene flow is a reality in the plant kingdom with evolutionary change. Herbicide resistance evolves naturally and spreads dynamically in weeds. One of the most concerning crop in relation to gene flow is Brassica napus, which has a high outcrossing rate and many relative species. In contrast, frequency of gene flow via outcrossing is relatively low in inbreeding cereal crops such as rice, wheat and barley, but published reports have shown that substantial gene flow is possible. Another possible and immediate risk is herbicide‐resistant GM crops becoming volunteer weeds. Dry direct‐seeded rice is one of the most likely crops in this respect. Stacking different resistance genes in a crop would accelerate multiple resistance evolution in weeds. Multiple resistance to three major herbicides has already been observed in oilseed rape cultivation. More efforts must be made for long‐term risk assessment on GM crops in the natural ecosystem. More studies on weed biology and ecology, particularly reproductive processes in weeds, are essential for better understanding of gene flow and systematic management strategy. We hope that this review motivates researchers to analyze data available now, to collect fundamental information on crops and weeds in agro‐ecosystem, and to lead to better risk assessment and management.     

转基因大豆外源基因的漂移风险

转基因作物外源基因的漂移已为国内外学者所证实。我国每年进口转基因大豆的数量巨大,转基因大豆外源基因的漂移对我国传统的大豆作物和生态环境是一个潜在威胁。本文论述了转基因大豆的概况和外源基因漂移的风险,并对进境转基因大豆的检测监管进行了思考。     

基于作物生长模型的农业干旱灾害风险动态评估

在阐述干旱灾害风险基本概念的基础上,分析了农业干旱灾害风险动态评估的难点。通过作物生长模型——DNDC模型模拟作物逐日生长,得到最终的粮食产量。采用情景分析方法,对不同气象条件下的作物产量进行估计,进而计算作物粮食因旱损失,实现农业干旱灾害风险动态分析。研究选择辽宁省为研究区,以玉米作物为代表,空间分析单元为县级行政区,利用15年的序列数据进行粮食因旱损失评估,模型模拟辽宁省的总误差控制在15%左右。风险分析结果表明,辽宁省西北部地区干旱灾害风险高于其他地区,这也与辽宁省干旱实际情况相吻合。     

Food safety assessment of crops engineered with RNA interference and other methods to modulate expression of endogenous and plant pest genes

Genetically modified crops have been grown commercially for more than two decades. Some of these crops have been modified with genetic constructs that induce gene silencing through RNA interference (RNAi). The targets for this silencing action are genes, either specific endogenous ones of the host plant or those of particular pests or pathogens infesting these plants. Recently emerging new genetic tools enable precise DNA edits with the same silencing effect and have also increased our knowledge and insights into the mechanisms of RNAi. For the assessment of the safety of foodstuffs from crops modified with RNAi, internationally harmonized principles for risk assessment of foods derived from genetically modified crops can be followed. Special considerations may apply to the newly expressed silencing RNA molecules, such as their possible uptake by consumers and interference with expression of host genes, which, however, would need to overcome many barriers. Bioinformatics tools aid the prediction of possible interference by a given RNA molecule with the expression of genes with homologous sequences in the host crop and in other organisms, or possible off‐target edits in gene‐edited crops. © 2020 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

作物抗旱基因研究进展及在马铃薯抗旱种质创新中的应用

整理并分析了近年来已经公开发表的68个抗旱相关基因,其中包括转录因子,以及提高渗透物质积累,具有解毒和抗氧化胁迫,控制作物生物大分子合成的基因,并对这些基因在作物抗旱中的作用机理及应用进展进行了分析。得出转录因子主要是通过激活或者抑制下游与干旱相关基因的表达,与渗透调节相关的基因主要是维持细胞内外渗透平衡,具有解毒和抗氧化胁迫的基因主要是通过清除活性氧的积累,与生物大分子合成有关的基因主要在逆境中可以产生一些逆境蛋白,从而提高作物耐逆性。同时整理并分析了利用基因工程改良马铃薯种质的发展现状与存在问题。     

Dealing with transgene flow of crop protection traits from crops to their relatives

Genes regularly move within species, to/from crops, as well as to their con‐ specific progenitors, feral and weedy forms (‘vertical’ gene flow). Genes occasionally move to/from crops and their distantly related, hardly sexually interbreeding relatives, within a genus or among closely related genera (diagonal gene flow). Regulators have singled out transgene flow as an issue, yet non‐transgenic herbicide resistance traits pose equal problems, which cannot be mitigated. The risks are quite different from genes flowing to natural (wild) ecosystems versus ruderal and agroecosystems. Transgenic herbicide resistance poses a major risk if introgressed into weedy relatives; disease and insect resistance less so. Technologies have been proposed to contain genes within crops (chloroplast transformation, male sterility) that imperfectly prevent gene flow by pollen to the wild. Containment does not prevent related weeds from pollinating crops. Repeated backcrossing with weeds as pollen parents results in gene establishment in the weeds. Transgenic mitigation relies on coupling crop protection traits in a tandem construct with traits that lower the fitness of the related weeds. Mitigation traits can be morphological (dwarfing, no seed shatter) or chemical (sensitivity to a chemical used later in a rotation). Tandem mitigation traits are genetically linked and will move together. Mitigation traits can also be spread by inserting them in multicopy transposons which disperse faster than the crop protection genes in related weeds. Thus, there are gene flow risks mainly to weeds from some crop protection traits; risks that can and should be dealt with. © 2014 Society of Chemical Industry     

麦蚜基因流地理信息系统的研制与开发

利用GIS技术和分子遗传标记对不同地理种群麦蚜的遗传结构、空间分布和发生动态等进行研究,以VC 为开发平台,以MapX控件作为图形平台,开发研制麦蚜基因流地理信息系统。本研究将微观的分子生态学和宏观的空间生态学有机地联系起来,为研究麦蚜的迁飞与预测预报提供了新的研究思路,这对于从理论上进一步揭示麦蚜的暴发机理和迁飞规律,从实践中有效地开展综合防治都具有重要的参考价值。     

转基因抗虫玉米环境安全性及我国应用前景

转基因抗虫玉米在生产上应用对于促进玉米增产、保障国家粮食安全具有巨大潜力。种植转基因玉米的环境安全性是公众对于应用这一生物技术产品最为关心的问题。本文从基因漂移、对玉米田节肢动物多样性的影响、靶标害虫的抗性及其治理策略和转基因抗虫玉米研发应用现状及其经济效益等方面对转基因抗虫玉米的生态影响研究进行了回顾,分析了种植转基因抗虫玉米的潜在生态风险,展望了我国转基因抗虫玉米的应用前景。     

黑龙江省农作物病虫测报信息管理与预测系统的开发

根据黑龙江省植保工作的实际需要,同时考虑全国各地植保系统应用的通用性,利用数据库技术和专家系统技术开发了农作物病虫测报信息管理与预测系统。该系统建立了比较完善的数据管理机制,将病虫害监测数据的管理与专家系统测报的应用有机结合起来,具有较强的灵活性和通用性等特点。本文介绍了系统的设计与开发,包括系统的整体结构与功能、系统病虫害信息数据库的设计及整个系统的数据关系、各主要功能模块的设计与实现等,并就未来应用发展的可能性进行了讨论。     

Integration of soil, crop and weed management in low-external-input farming systems

Greater adoption and refinement of low-external-input (LEI) farming systems have been proposed as ways to ameliorate economic, environmental and health problems associated with conventional farming systems. Organic soil amendments and crop diversification are basic components of LEI systems. Weed scientists can improve the use of these practices for weed management by improving knowledge of four relevant ecological mechanisms. First, multispecies crop rotations, intercrops and cover crops may reduce opportunities for weed growth and regeneration through resource competition and niche disruption. Secondly, weed species appear to be more susceptible to phytotoxic effects of crop residues and other organic soil amendments than crop species, possibly because of differences in seed mass. Thirdly, delayed patterns of N availability in LEI systems may favour large-seeded crops over small-seeded weeds. Finally, additions of organic materials can change the incidence and severity of soil-borne diseases affecting weeds and crops. Our research on LEI sweetcorn and potato production systems in central and northern Maine (USA) suggests that these mechanisms can reduce weed density and growth while maintaining crop yields. Low-external-input farming systems will advance most quickly through the application of interdisciplinary research focused on these and other ecological mechanisms.     

开放式网络病虫信息管理平台的组建与实现

为有效管理和利用植物保护系统的各种病虫资料信息,应用网络脚本语言PHP、网络服务器Apache及MySQL数据库构建了一套基于网络的病虫信息管理系统。系统采用开放式的设计模式,组建了用户管理模块、动态树型菜单模块、在线建表模块、数据表管理模块、日程提醒模块、资料统计对比模块、图形显示模块等。用户可根据自己需要在线建立数据表;系统将动态树型菜单与在线建表模块相互结合,实现了对各种表格的管理,包括表格的创建、数据的查询、汇总、比较及图形化显示等功能,用户通过Internet在系统的帮助下,可建立适合本地实际、满足自己需要的病虫信息管理系统。     

Crop and density effects on weed beet growth and reproduction

Weed beet populations growing in each crop of the arable rotation could be a relay for the gene flow from adjacent transgenic herbicide‐resistant sugarbeet. In this study, weed beet growth and reproduction were assessed under several conditions which could be found in the rotation: various weed beet densities (ranging from 1 to 120 plants m^?2) and various crops (winter wheat, spring barley, spring pea, sugarbeet, maize, ryegrass). Measurements were carried out both on life‐cycle dynamics (bolting time, time to flowering onset, dynamics of flower opening) and on other quantitative data (survival rate, bolting rate and pollen, flower and seed production). Increasing weed beet density resulted in decreases in bolting rate and flower and seed production per plant. In cereals, weed beet establishment and reproduction were strongly reduced, compared with bare ground as a control situation. In pea, there was no effect on establishment, but the early harvest limited seed set. In the other crops, flower and seed production were reduced to a lesser extent. Parameters of the fitted equations on the bolting and flowering progress were modified by the weed beet density and by the crop. Our data may be used in a model predicting weed beet demographic evolution according to cropping system, and in assessing gene flow.     

Analysis of the seed dispersal patterns of wild soybean as a reference for vegetation management around genetically modified soybean fields

There are concerns that genetically modified soybean might threaten the genetic diversity of the wild soybean populations that are distributed in East Asia because genetically modified soybean has no crossing barrier with wild soybean. A simple and effective method to prevent hybridization via pollen flow is spatial separation between the two species because their hybridization occurs only when they grow in close proximity. Therefore, the invasiveness of wild soybean needs to be known in order to secure the appropriate distances. As wild soybean seeds are dispersed mechanically by pod dehiscence, an experiment was conducted in which white sheets were placed on the ground, concentric circles were drawn around the parent plants, and the number of dispersed seeds within each 0.5 m‐wide zone were counted. About 40% of the produced seeds were dispersed and the number of dispersed seeds gradually declined as the distance from the parent plants increased. The model that explained the relationship between the number and distance of the dispersed seeds was produced by using a generalized linear model procedure. More than 95, 99, and 99.9% of the produced seeds stayed within 3.5, 5.0, and 6.5 m after natural pod dehiscence. Knowing these values is useful for evaluating the level of invasive risk by mechanical seed dispersal. The goal of the work is to efficiently and deliberately prevent hybridization by isolating genetically modified soybean fields and wild soybean populations by vegetation management, including weeding and setting up specific‐width buffer zones.     

Hybridisation between wheat and Aegilops geniculata and hybrid fertility for potential herbicide resistance transfer

Hybridisation between wheat and Aegilops geniculata was quantified in a 4‐year crossing experiment in the glasshouse, using three wheat cultivars as pollen donors and herbicide resistance as a phenotypic marker. Hybridisation rates ranged from 5% to 74%. Most of the hybrids were self‐sterile. However, seven F₂ seeds were obtained from 165 A. geniculata–wheat hybrids. Hybrid seeds were found in all backcross (BC₁) combinations at average rates of 4.2% (0–26.3%) and 5.88% (0–34%) under glasshouse and field experiments, respectively, with significant differences among years and cultivars. Wheat cultivars, F₁ and BC₁ plants, were resistant to herbicides while A. geniculata plants were susceptible. In the subsequent generations, although few plants were available, the BC₁F₁ had a certain degree of fertility and the fertility increased in the F₂ plants, with one plant that reached 66.7%. The commercial growing of genetically modified herbicide‐tolerant wheat is expected to have the potential for the inserted gene to escape from the crop and become incorporated in a closely related wild species, conferring a competitive advantage to these conferring weeds. Determining the frequency of crop‐wild transgene flow and the fertility of the formed hybrids is a necessity for risk assessment. Data presented here provide new knowledge on the potential A. geniculata–wheat herbicide resistance transfer.     

A comparison of crop and non-crop plants as sensitive indicator species for regulatory testing

The effectiveness of regulatory non-target plant testing using crop species to predict the phytotoxicicity of herbicides to non-crop species was evaluated for eleven herbicides. These herbicides were representative of eight chemical classes and six modes of action. Data for non-crop plants from pre-emergence and post-emergence efficacy screening studies were compared with those for the most sensitive crop species defined by regulatory tests conducted to meet US EPA requirements. Testing under pre-emergence conditions for ten compounds indicated that for five of the compounds (K-815910, trifluralin, pyridyloxy A, pyridyloxy B and cyanazine), the most sensitive crop species was more sensitive than all the non-crop species evaluated. For metsulfuron-methyl, chlorimuron-ethyl, hexazinone and bromacil, only one of the non-crop species evaluated was more sensitive than the most sensitive crop species from regulatory tests. Data for the tenth compound, chloroacetamide, showed that four of 32 non-crop species tested in efficacy screens had at least one rate at which greater visual effects were observed than were observed for the most sensitive crop response in a regulatory test. The results of post-emergence exposure comparisons for five of the compounds (pyridyloxy A, cloransulam-methyl, chlorimuron-ethyl, cyanazine and hexazinone) indicated that the most sensitive crop species were more sensitive than all the non-crop species evaluated. Data for pyridyloxy B, metsulfuron-methyl and bromacil indicated that only one of the non-crop species evaluated was more sensitive than the most sensitive crop species. For trifluralin, three of the eight non-crop species were more sensitive than the most sensitive crop species. Data for K-815910 indicated that four of the fourteen non-crop species tested were marginally more sensitive than the most sensitive crop, but were within the same range of sensitivity. These results indicate that the current regulatory test batteries and methods using crop species effectively provide suitable sensitive indicator plants for the eleven diverse herbicides evaluated. This comparison indicates that crop species sensitivity to test substances is likely to be representative of non-crop herbaceous species response, regardless of chemical class, mode of action and magnitude or route of exposure.     

黄瓜中醚菌酯的残留及风险评估

建立了醚菌酯在黄瓜中的残留分析方法,并在广州和天津进行了30%醚菌酯可湿性粉剂在黄瓜上残留的田间试验,研究了醚菌酯在黄瓜上的消解动态和最终残留,采用风险商值法对黄瓜中醚菌酯可能产生的膳食风险进行了评估。黄瓜样本用乙腈提取,高效液相色谱-串联质谱法(HPLC-MS/MS)检测。在添加水平为0.01、0.05和0.5 mg/kg时,平均添加回收率在91%～95%之间,相对标准偏差为3.74%～9.99%,检出限(LOD)为0.001 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明,醚菌酯在广州和天津黄瓜中的半衰期分别为1.5 d和2.1 d,消解迅速,施药3 d后最终残留量为0.08～0.23 mg/kg,施药5 d后最终残留量均低于LOQ值。风险评估结果表明,施药后3 d时黄瓜中醚菌酯的残留风险商值均远远低于1。表明喷施30%醚菌酯可湿性粉剂防治黄瓜白粉病,按照推荐剂量使用对人体健康是安全的。     

Sugar concentration in nectar: a quantitative metric of crop attractiveness for refined pollinator risk assessments

Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively, this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues; seasonal availability; physical and behavioral characteristics of the bee; plant and nectar rewards. Notwithstanding the complexities and interactions among these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a crop attractiveness factor) in the calculation of risk quotients in order to derive crop‐specific tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

黑龙江大豆生产时空分析与风险评估

基于黑龙江省大豆产量锐减和自然灾害加重的背景,依据1993—2012年13个地市和农垦总局(ARB)20 a的产量数据,运用数理统计和单产分布模拟推导法,分析了黑龙江大豆产量时空变化,并评估了相应的生产风险。结果表明:2005年黑龙江大豆产量达到峰值748万t,2012年产量直线下降至463.4万t;2012年,齐齐哈尔、农垦总局和黑河为黑龙江三大主产区,产量占全省的55.73%,发生灾害的概率分别为41.61%、18.78%和41.11%,全省灾害发生概率最高的是大兴安岭46.42%,最低的是农垦总局18.78%;齐齐哈尔和黑河作为黑龙江大豆主产区,灾害风险相对较高,在灾害防御投入、政策补贴等方面应优先考虑。     

Bt棉对斑痣悬茧蜂寄主选择及其子代发育的影响*

［目的］ 评价转Bt基因棉通过非靶标寄主斜纹夜蛾和甜菜夜蛾幼虫对寄生蜂的影响。［方法］ 分别采用选择性试验和非选择性方法,观察斑痣悬茧蜂对取食Bt棉叶和常规棉叶的斜纹夜蛾和甜菜夜蛾幼虫的产卵选择偏好,并观察子代蜂在不同处理幼虫体内的发育表现。［结果］ 取食Bt棉叶的斜纹夜蛾幼虫体重与取食常规棉叶的没有显著差异,而取食Bt棉叶的甜菜夜蛾幼虫体重显著小于取食常规棉叶。对斜纹夜蛾幼虫的选择性试验表明,斑痣悬茧蜂未表现出对取食Bt棉寄主幼虫的偏好。［结论］ 斑痣悬茧蜂子代的历期、存活以及羽化成蜂的体型大小等发育适应度特征,不受寄主幼虫所取食的食料植物的影响。     

叶菌唑在小麦中的残留消解及膳食风险评价

为评价叶菌唑在小麦中的残留行为及其产生的膳食摄入风险,于北京、安徽及黑龙江进行了1年3地田间试验,建立了叶菌唑在小麦中的残留分析方法,并对我国不同人群的膳食暴露风险进行了评价。样品用乙腈提取,经Florisil固相萃取柱净化,气相色谱-氮磷检测器(GC-NPD)检测,外标法定量。结果表明:在0.02~10 mg/kg的添加水平下,叶菌唑在小麦籽粒和植株中的平均回收率在81%~101%之间,相对标准偏差(RSD)在2.1%~9.1%之间;其在小麦籽粒和植株中的定量限(LOQ)分别为0.02和0.04 mg/kg。叶菌唑在小麦植株中的消解符合一级动力学方程,半衰期为4.9~7.3 d。收获时小麦籽粒中叶菌唑的最大残留量为0.037 mg/kg,低于美国和欧盟设定的最大残留限量(MRL)0.15 mg/kg。针对我国不同人群的膳食摄入及风险评估暴露,风险商值(RQ)在0.001~0.002之间,表明叶菌唑在小麦中的膳食摄入风险较低。