植物呼肠孤病毒研究的最新进展

植物呼肠孤病毒是一类形态复杂、具有多种病毒结构蛋白及片段化双链RNA基因组的病毒,一直受到病毒学家的注意。植物呼肠孤病毒对媒介昆虫的侵染不表现细胞病理     

植物病毒卫星研究进展

植物病毒卫星研究进展周雪平,李德葆（浙江农业大学生物技术研究所,杭州３１００２９）自６０年代Ｋａｓｓａｎｉｓ发现有些烟草坏死病毒（ＴＮＶ）分离物中含有１７ｎｍ的病毒颗粒,并将其称谓卫星烟草坏死病毒（ＳＴＮＶ）以来,已发现多种植物ＲＮＡ病毒含有卫星（Ｓ...     

植物双生病毒研究进展

双生病毒（Ｇｅｍｉｎｉｖｉｒｕｓ）是一组具有双生颗粒形态的单链环状ＤＮＡ植物病毒［１～３］。典型的双生病毒为１８×３０ｎｍ颗粒,基因组大小为２．５～３．０ｋｎｔ。双生病毒研究已成为植物病毒学最活跃的领域之一。１双生病毒的性质１．１双生病毒组的成员划分...     

植物病毒的卫星病毒和卫星RNA

植物病毒的卫星病毒和卫星ＲＮＡ陈金标（南京农业大学微生物系２１００９５）病毒是一种无细胞结构的生物体,个体极小,约为２０—４００ｕｒｎ。Ｍａｔｔｈｅｗｓ将它定义为：病毒是丁组或多组核酸分子、它通常祛外完蛋白包裹,且只在适合的寄主细胞里复制。在这种细胞...     

植物源病毒抑制剂的研究进展

天然植物提取的活性物质对植物病毒有明显的抑制作用,已经成为当今植物病毒防治的重点。对植物源病毒抑制的活性物质及作用机理的研究现状进行了综述,并将外来入侵生物用以提取病毒抑制剂的相关生物技术提出了展望。     

RNA沉默与植物病毒

植物中RNA沉默（RNAsilencing)亦称为转录后基因沉默（PTGS）或共抑制,是植物抵抗外来核酸（转座子、转基因或病毒）入侵,并保护自身基因组完整性的一种防御机制。RNA沉默是近十年来发现的植物界中普遍存在的现象,已成为植物分子生物学领域的一个新的研究方向。对RNA沉默特点和机制的研究表明,植物病毒与（转基因）植物内发生的RNA沉默有着密切的联系,作者从病毒对RNA沉默的诱导、抑制、防御等方面,简述了RNA沉默与病毒的关系。并对病毒载体所诱导的RNA沉默在植物发育和基因组功能分析等方面的应用价值进行了讨论。     

植物病毒及其危害

病毒是至今人们所知的在自然界最小的生物之一,其形态大小要借助电镜放大到几万甚至几十万倍才能观察得到。它具有严格的寄生性。必须在宿主细胞内才能生长繁殖。植物病毒作为重要的病原物,可通过多途径传播,在全世界范围内引起农作物严重的病害。目前多采用综合措施防治以减轻病害,尚未有彻底的根治方法。     

植物病毒病媒介昆虫的传毒特性和机制研究进展

植物病毒病是农作物的“癌症”, 至今缺少有效的防治方法。目前已知80%的植物病毒病依赖于媒介昆虫传播, 而媒介昆虫对植物病毒的传播是一个昆虫、 病毒、 寄主植物互作的过程, 历经获毒、 持毒和传毒等多个阶段, 昆虫体内一系列病毒受体或蛋白参与了这个过程。昆虫传播病毒的方式有口针携带式、 前肠保留式和体内循环式3类, 它们各自对应的持久性为非持久性、 半持久性和持久性, 不同昆虫获取这3类病毒的获毒时间、 在体内存留位置和传毒时间也各不相同。 这个过程受到媒介昆虫的性别及龄期、 寄主植物、 环境条件、 昆虫体内共生菌等多种因素的影响。与之相关的蛋白主要有病毒衣壳蛋白(CP)、 次要衣壳蛋白（CPm）、 GroEL蛋白、 辅助因子(HC)和下颚口针蛋白等。近年来对植物病毒基因组的研究也取得了很大的进展, 对昆虫传毒机制的研究正受到越来越广泛的关注。本文综述了近年来该领域内的相关研究进展, 包括昆虫传播植物病毒的传毒方式、 影响传毒效率的因素、 传毒机制特别是昆虫体内与病毒传播可能相关的受体等。     

Probable reassortment of genomic elements among elongated RNA-containing plant viruses

Summary The relationships of genome organization among elongated (rod-shaped and filamentous) plant viruses have been analyzed. Sequences in coding and noncoding regions of barley stripe mosaic virus (BSMV) RNAs 1, 2, and 3 were compared with those of the monopartite RNA genomes of potato virus X (PVX), white clover mosaic virus (WClMV), and tobacco mosaic virus, the bipartite genome of tobacco rattle virus (TRV), the quadripartite genome of beet necrotic yellow vein virus (BNYVV), and icosahedral tricornaviruses. These plant viruses belong to a supergroup having 5-capped genomic RNAs. The results suggest that the genomic elements in each BSMV RNA are phylogenetically related to those of different plant RNA viruses. RNA 1 resembles the corresponding RNA 1 of tricornaviruses. The putative proteins encoded in BSMV RNA 2 are related to the products of BNYVV RNA 2, PVX RNA, and WClMV RNA. Amino acid sequence comparisons suggest that BSMV RNA 3 resembles TRV RNA 1. Also, it can be proposed that in the case of monopartite genomes, as a rule, every gene or block of genes retains phylogenetic relationships that are independent of adjacent genomic elements of the same RNA. Such differential evolution of individual elements of one and the same viral genome implies a prominent role for gene reassortment in the formation of viral genetic systems.     

Evidence for plant viruses in the region of Argentina Islands, Antarctica

This work focused on the assessment of plant virus occurrence among primitive and higher plants in the Antarctic region. Sampling occurred during two seasons (2004/5 and 2005/6) at the Ukrainian Antarctic Station 'Academician Vernadskiy' positioned on Argentina Islands. Collected plant samples of four moss genera (Polytrichum, Plagiatecium, Sanionia and Barbilophozia) and one higher monocot plant species, Deschampsia antarctica, were further subjected to enzyme-linked immunosorbent assay to test for the presence of common plant viruses. Surprisingly, samples of Barbilophozia and Polytrichum mosses were found to contain antigens of viruses from the genus Tobamovirus, Tobacco mosaic virus and Cucumber green mottle mosaic virus, which normally parasitize angiosperms. By contrast, samples of the monocot Deschampsia antarctica were positive for viruses typically infecting dicots: Cucumber green mottle mosaic virus, Cucumber mosaic virus and Tomato spotted wilt virus. Serological data for Deschampsia antarctica were supported in part by transmission electron microscopy observations and bioassay results. The results demonstrate comparatively high diversity of plant viruses detected in Antarctica; the results also raise questions of virus specificity and host susceptibility, as the detected viruses normally infect dicotyledonous plants. However, the means of plant virus emergence in the region remain elusive and are discussed.     

Lifestyles of plant viruses

The vast majority of well-characterized eukaryotic viruses are those that cause acute or chronic infections in humans and domestic plants and animals. However, asymptomatic persistent viruses have been described in animals, and are thought to be sources for emerging acute viruses. Although not previously described in these terms, there are also many viruses of plants that maintain a persistent lifestyle. They have been largely ignored because they do not generally cause disease. The persistent viruses in plants belong to the family Partitiviridae or the genus Endornavirus. These groups also have members that infect fungi. Phylogenetic analysis of the partitivirus RNA-dependent RNA polymerase genes suggests that these viruses have been transmitted between plants and fungi. Additional families of viruses traditionally thought to be fungal viruses are also found frequently in plants, and may represent a similar scenario of persistent lifestyles, and some acute or chronic viruses of crop plants may maintain a persistent lifestyle in wild plants. Persistent, chronic and acute lifestyles of plant viruses are contrasted from both a functional and evolutionary perspective, and the potential role of these lifestyles in host evolution is discussed.     

植物比较解剖学在中国50年的进展和展望

系统与进化植物学是当今植物科学中的主流学科之一,植物比较解剖学是该学科的重要组成部分。根据近50年国内主要期刊统计,我国植物学者重点在种子植物的维管组织结构、叶及其表皮结构、花的结构和发育、种子及种皮特征、分泌组织以及一些原始种子植物等方面开展了比较解剖研究,为一些植物科、属的系统分类提供了解剖学依据。但在研究的植物种类、内容和方法尚存在不足,发表的论文相对较少。根据我国植物种质资源丰富,研究基础较好等特点,认为我国植物比较解剖学发展前景宽广,并对进一步发展提出一些建议。     

Eustatic changes during the last 300 years

Tide gauges in rising and subsiding areas show a major change in the shore-level displacement at about A.D. 1840, caused by the onset of a rapid eustatic rise. Comparisons between information from Amsterdam, Stockholm and Warnemünde provide material for the reconstruction of the eustatic changes during the last 290 years. Relative uplift data from the Swedish west coast, corrected according to the eustatic curve established here, give the same location of the isostatic zero isobase as does the geological material for the last 7,000 years. The eustatic changes closely follow climatic changes. A rapid eustatic rise started about 1840, slowed down about 1930 and ended about 1950. Knowing the eustatic factor, the isostatic (or tectonic) factor is calculated for different areas of importance in the discussion of Holocene eustatic sea-level changes.     

东北地区近44年的气候暖干化趋势分析及可能影响

东北地区位于我国最高纬度,是受全球气候变暖影响增温最显著的地区之一,有其独特的气候变化特点。利用东北地区近44年来较密集的气象观测资料,运用Yamamoto检测、趋势系数和气候倾向率等方法分析了该区域的气候时空变化规律、突变特征和暖干化趋势等,并初步探讨了这种变化对生态环境的可能影响。结果表明,东北地区总体气候变化存在暖干化倾向,气候暖干化趋势存在着季节性差异和地域性差异,暖干化趋势在夏、秋季及环境脆弱区的三江平原和科尔沁沙地及周边地区表现更为明显,由此引起的生态环境变化问题应引起重视。     

近40年东北地区陆栖脊椎动物种群数量及其生境变化评估

生物多样性是生态平衡维持和生态过程与功能实现的基础,东北地区是我国乃至全球生物多样性最为丰富的地区之一。为研究和探讨东北地区陆栖脊椎动物种群数量与生境变化之间的关系,利用物种调查数据和生境遥感观测数据,以地球生命力指数、生态系统面积和破碎度等指示性指标,综合评估了近40年东北地区陆栖脊椎动物种群数量及其生境变化。结果表明:1970—2010年,东北地区陆栖脊椎动物种群数量下降了近70.1%,森林脊椎动物种群数量减少了近80.9%,草原和荒漠生态系统脊椎动物种群数量增加了近180.9%。1980—2010年,湿地物种种群数量减少了近75.7%。1980—2015年期间,农业和城镇建设用地增幅分别达到25.2%和32.3%,不断挤占和蚕食着自然生态空间,致使自然生境面积不断减少,减幅约为8.0%。自然生境景观破碎化程度总体呈现加重趋势,尤其是森林生境,破碎化指数增加约42.7%。但是,2005年之后,自然生境景观破碎化程度加重趋势趋缓,与2005年之后脊椎动物种群数量减少幅度减缓趋势一致。森林砍伐、人口增长、城镇化、交通建设等造成的自然生态系统破碎度增加和栖息地质量下降对大型兽类影响比较显著。