生物多样性 ›› 2016, Vol. 24 ›› Issue (2): 205-215.DOI: 10.17520/biods.2015127

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植原体遗传多样性研究现状与展望

于少帅1,2, 徐启聪1, 林彩丽1, 王圣洁1, 田国忠1,,A;*()   

  1. 1 .中国林业科学研究院森林生态环境与保护研究所, 国家林业局森林保护学重点实验室, 北京 100091
    2 自然农法国际研究开发中心, 日本国松本市 3901401
  • 收稿日期:2015-05-12 接受日期:2015-09-06 出版日期:2016-02-20 发布日期:2016-03-03
  • 通讯作者: 田国忠
  • 基金资助:
    国家自然科学基金(31370644)和国家微生物资源平台项目(NIMR2014-7)

Genetic diversity of phytoplasmas: research status and prospects

Shaoshuai Yu1,2, Qicong Xu1, Caili Lin1, Shengjie Wang1, Guozhong Tian1,*()   

  1. 1 Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Forest Protection of State Forestry Administration, Beijing 100091, China
    2 International Nature Farming Research Center, Matsumoto 3901401, Japan
  • Received:2015-05-12 Accepted:2015-09-06 Online:2016-02-20 Published:2016-03-03
  • Contact: Tian Guozhong

摘要:

植原体是引起众多植物病害的一类重要的无细胞壁的原核致病菌, 其寄主种类多、危害面积广, 对经济、环境等影响严重。大量研究表明植原体存在丰富的遗传多样性。本文就植原体遗传多样性研究现状作一概要评述, 并对植原体遗传变异的研究技术、产生机制、与致病性关系等今后可能的研究方向作一展望。对已完成的5个植原体全基因组序列分析发现, 它们在大小、结构和功能等方面皆存在显著差异, 缺少很多标准代谢所需的基因。不同植原体中质粒的数量、大小和功能等也存在一定差异。植原体含有2个核糖体RNA编码基因, 其序列在不同株系中的变异奠定了现今植原体分类鉴定的基础。对植原体蛋白编码基因如核糖体蛋白编码基因(rp)、蛋白延伸因子基因(tuffusA)、转运蛋白基因(secYsecA)、效应子及非编码区序列如启动子、假基因等的深入研究可进一步揭示植原体更丰富的遗传变异特征。由于植原体分离培养困难, 人们对其形态特征、生理代谢等了解甚少, 因而全基因组测序、多位点序列分析等现代分子生物学技术将会成为植原体遗传变异研究的主要手段。植原体遗传多样性研究进展有助于从分子水平上系统地阐明植原体遗传变异规律、系统进化特征及其与寄主(植物和昆虫)、生态环境间的互作和适应关系, 并产生新的认识。这对于提高植原体的分类鉴定、致病机制、流行预测及病害防治等研究水平具有重要的作用和意义。

关键词: 植原体, 遗传变异, 系统进化, 分类鉴定, 植物(介体昆虫)-植原体互作, 多位点序列分析(MLSA)

Abstract

Phytoplasmas are cell wall-less prokaryotic pathogens causing many plant diseases with various host plants, widely geographical distribution and adverse impacts on economics and environments. Abundant genetic diversity of the phytoplasmas has been evidenced by vast researches. In the paper, we conducted a comparatively systematic and comprehensive schematic review and comment on the research status of phytoplasma genetic diversity. We discussed the potential research directions with respect to research technology and generation mechanism of phytoplasmal genetic variation as well as relationships to pathogenicity in future. Analysis on five phytoplasmas whose whole genomes have been completed has indicated the definite genetic variation in size, structure and function of phytoplasmal genomes, which lack many genes for standard metabolic functions. There are different number, size and function of the plasmids in various phytoplasma strains. Two copies of ribosomal RNA operons among all the phytoplasmas showed significant variation which provided the present foundation for classification and identification of phytoplasmas. Studies on protein-encoding genes, such as ribosomal protein (rp), elongation factors (tuf and fusA), translocation proteins (secY and secA), effector molecules as well as non-encoding sequences such as promoters and pseudogenes have further revealed the rich genetic diversity of phytoplasmas. Since inadequate information is known regarding the characteristics of morphology, cultivation, physiology and metabolism due to the difficulty in culturing phytoplasma in vitro, modern molecular techniques for example whole genome sequencing and multilocus sequence analysis (MLSA) are efficient ways to research phytoplasmal genetic variation. Discoveries and developed techniques have facilitated a system-wide approach to revealing phytoplasma genetic variation, phylogenetic evolution as well as the relationships of their interaction with hosts (plant and insect vector) and adaptation to ecological conditions from the molecular level, and led to new insights. This will be of great importance in increasing the level of classification and determination of phytoplasmas, epidemiological forecasting and the control of relevant diseases.

Key words: phytoplasma, genetic variation, phylogenetic evolution, classification and identification, plant (insect vector)-phytoplasma interaction, multilocus sequence analysis (MLSA)