茶树是重要经济作物,因其叶片是世界范围内普遍使用的饮品原料。中国作为主要的茶叶生产和消费国,商业市场中拥有种类繁多的茶产品;但是,茶叶加工制作后对其外观的改变,严重影响对茶叶产品的植物品种来源的纯度鉴定。DNA条形码技术是一种利用种间特异性的基因序列信息快速、精准鉴定物种类型的分子检测的较新方法,其目前已越来越多的应用于动植物及真菌等的生物多样性研究中。因此,将DNA条形码技术应用于茶产品的鉴定,具有保质和防伪的茶业市场运用价值。本文从DNA条形码技术及其在茶叶中的研究进展角度出发,主要总结了该技术应用于茶叶(生产)上的现状以及存在的实践技术问题,探讨了基于DNA条形码分析手段提高茶叶品种鉴定精准确度和效率的可能性新方法。 Tea plant (Camellia sinensis L.) represents an important commercial crop, because its leaves are used worldwide as direct and raw material for a beverage(s). China is a major tea producing- and consuming-country, and a large variety of commercial tea products occur in Chinese market; however, because of a strong change of a leaf shape or appearance by a manufactory processing, it makes difficult to effectively distinguish/identify the purity of a tea product originated from a given plant species. The DNA barcoding technology, a recently emerged molecular approach for quick and accurate identification of a genotype of (intra) species on the base of (intra) species- specific gene sequence information, has been increasingly applied to investigate a bio-diversity of animals, plants and fungi, etc. Thus, the use of the DNA barcoding techniques for distinguishing tea products has an application value in relation to protecting quality and anti-counterfeiting in tea- industry and market. In this review, from a viewpoint of DNA barcoding technology and its use in tea plant research advance, we have mainly summarized the present application status and practical limitation of this technology as applied in the tea production, and discussed a possible new methodology aiming at improving an accuracy and efficiency for testing or identifying tea varieties based on DNA barcoding analysis.
茶树是重要经济作物,因其叶片是世界范围内普遍使用的饮品原料。中国作为主要的茶叶生产和消费国,商业市场中拥有种类繁多的茶产品;但是,茶叶加工制作后对其外观的改变,严重影响对茶叶产品的植物品种来源的纯度鉴定。DNA条形码技术是一种利用种间特异性的基因序列信息快速、精准鉴定物种类型的分子检测的较新方法,其目前已越来越多的应用于动植物及真菌等的生物多样性研究中。因此,将DNA条形码技术应用于茶产品的鉴定,具有保质和防伪的茶业市场运用价值。本文从DNA条形码技术及其在茶叶中的研究进展角度出发,主要总结了该技术应用于茶叶(生产)上的现状以及存在的实践技术问题,探讨了基于DNA条形码分析手段提高茶叶品种鉴定精准确度和效率的可能性新方法。
中国茶叶类,DNA条形码,市场运用
Yucheng Xiang, Changzheng Wu, Laihua Liu*, Song Sheng*
College of Resources and Environmental Sciences, China Agricultural University, Beijing
Received: Aug. 9th, 2021; accepted: Sep. 17th, 2021; published: Sep. 29th, 2021
Tea plant (Camellia sinensis L.) represents an important commercial crop, because its leaves are used worldwide as direct and raw material for a beverage(s). China is a major tea producing- and consuming-country, and a large variety of commercial tea products occur in Chinese market; however, because of a strong change of a leaf shape or appearance by a manufactory processing, it makes difficult to effectively distinguish/identify the purity of a tea product originated from a given plant species. The DNA barcoding technology, a recently emerged molecular approach for quick and accurate identification of a genotype of (intra) species on the base of (intra) species-specific gene sequence information, has been increasingly applied to investigate a bio-diversity of animals, plants and fungi, etc. Thus, the use of the DNA barcoding techniques for distinguishing tea products has an application value in relation to protecting quality and anti-counterfeiting in tea-industry and market. In this review, from a viewpoint of DNA barcoding technology and its use in tea plant research advance, we have mainly summarized the present application status and practical limitation of this technology as applied in the tea production, and discussed a possible new methodology aiming at improving an accuracy and efficiency for testing or identifying tea varieties based on DNA barcoding analysis.
Keywords:Chinese Teas, The DNA Barcoding Technology, An Application of Market
Copyright © 2021 by author(s) and Hans Publishers Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY 4.0).
http://creativecommons.org/licenses/by/4.0/
茶(Camellia sinensis)源自中国,已有2000余年历史。公元六世纪传至海外,现今茶树种植已遍及全世界60余个国家,饮茶文化遍布全球。作为世界三大饮料之一的茶叶,其市场需求巨大。但在茶叶的销售过程中,存在通过向高价茶掺入外观接近的其他品种茶叶或者以次充好用低价茶来冒充高价茶叶等掺假手段,更甚者,以同品种低端茶冒充高端茶以获取不当收益。以保靖黄金茶为例,逐步改良过后的茶叶品种“黄金茶1号”所产茶叶是杂树茶叶售卖价格的一倍以上。目前,市场上的茶产品已逾数百种,因其制茶工艺的多样化,经过初/精加工后的茶叶已很难简单通过人工感官检测或借助机械辅助检测。虽然部分技术如高光谱图像技术 [
DNA条形码(DNA barcoding)技术于2003年首次被加拿大教授Paul Hebert提出 [
目前,全球范围内科学家们已建立了多个DNA条形码数据库。现阶段,加拿大生物多样性基因组学中心开发的BOLD数据库(The Barcoding of Life Data System, http://www.boldsystems.org)较为领先,至今已收录966.1万条DNA条形码(其中71.9万已有条形码索引码BIN,Barcoding Index Number),覆盖23.2万种动物、7万种植物、2.4万种真菌及其他生物 [
我国地大物博,植物资源丰富,对精确鉴定植物种类有较大需求。早在2009年,因陈士林课题组在植物DNA条形码筛选中的突出成绩,国际生物条形码协会(Consortium for the Barcoding of Life,CBOL)邀请其在“第三届国际条形码大会”上做了题为“为何选择ITS2序列作为植物条形码”和“ITS2”序列作为通用条形码序列鉴定药用植物”的两个学术报告,并将ITS2(internal transcribed spacer 2)作为补充条形码序列进行评估。现今,药用植物、藻类、烟草等物种DNA条形码的研究已取得卓越进展。
为快速鉴定疑似烟草制品中是否含有烟草成分以及判定非法贩卖的假烟制品,白戈等 [
DNA条形码鉴定标准化流程如下:1) DNA条形码的序列分析,获取鉴定物种的序列信息,进行多序列比较,计算遗传距离,运用多种方法筛选候选DNA序列,早期CBOL建议植物选取叶绿体DNA上的片段居多,近年来逐渐有新的候选片段加入。2) DNA条形码序列校对,对第一步中得到的序列进行验证,因试验过程中存在如样品污染、样品不准确、测序过程错误等,都会影响序列的获取;3) 评估DNA条形码的物种鉴定能力,包括但不限于BLAST搜索鉴定(BLAST-based Method)以及不同序列间遗传距离比较(Distance-Based Method),或进行基于系统进化关系的重建(Tree-Based Method)等;4) 最后在实际生产中提取样品DNA,测序比对现有DNA条形码库,鉴定样品品种信息。
2011年,Stoeckle等 [
相较于分类学(Taxonomy)的广泛应用,如今DNA条形码技术,多为科学研究的一种方法,实际生产中的应用正在研究和推广普及中。虽然该技术能利用标准的、有足够变异的、易扩增且相对较短的DNA片段对物种进行快速鉴定,但即使通过大量测序,获取到具备鉴定条件的DNA条形码片段后,在一线生产中仍存在由测序仪器和操作人员培训难导致的成本高、过程较长等问题。高分辨率溶解分析(High-resolution melting analysis, HRM)是一门新兴的技术,与传统不饱和燃料SYBR Green I用于RT-qPCR不同,HRM应用的饱和燃料(LC Green,LC Green Plus和SYTO9等)将饱和DNA双螺旋结构中的小沟,使得DNA解链过程中不会发生重排,使得其溶解曲线由更高的分辨率,进而微小的一个碱基突变也能检测其产生的解链温度差异,虽然温差仅为零点几摄氏度。HRM仪器运行步骤和对应原理如下:HRM首先对PCR的扩增子进行加热,温度从50度逐渐上升到95度。在此过程中,扩增子逐渐解链,在达到溶解温度(Tm)时,DNA链完全分开。在HRM分析初期,荧光强度很高,随着温度升高,双链NA逐渐减少,荧光强度下降,而HRM仪器通过高频相机,记录下荧光变化的整个过程,形成能鉴别细小溶解曲线差异的最终图形,进而通过算法鉴定序列的微小差异。相较于经典的DNA条形码鉴定流程,Lagiotis等 [
最后,根据现有信息,提出未来全方位鉴定茶叶品种DNA条形码的预测方案:a) 两倍体茶树的基因组含有15对染色体(2n = 30),约包含约3.5至3.8 Gb。由于阿萨姆茶(Camellia sinensis var. assamica, CSA)和中国茶(Camellia sinensis var. sinensis, CSS)基因组的草图分别完成于2017和2018年 [
向禹澄,吴长征,刘来华,盛 崧. DNA条形码技术在茶叶品种鉴定中的研究现状及展望Research Status and Prospects of DNA Barcoding Technology in Tea Varieties Identification[J]. 植物学研究, 2021, 10(05): 734-738. https://doi.org/10.12677/BR.2021.105092