标本组学——树木学研究的新方法

Herbariomics:a new and powerful approach for dendrological studies

树木学是一门不断发展、高度综合的学科。系统发生是树木学的基础,研究材料和序列数据一直是限制系统发生重建的重要因素。新技术的发展和应用通过拓展材料利用、改进和提升系统发生树的分辨率而将树木学的研究推向新的高度。标本馆不仅是树木物种凭证标本的保存地,保存了物种的形态、地理分布、生态、物候等信息,而且是重要的材料库。标本材料因制作和保存过程中高温和氧化导致基因组DNA降解和破碎化,一代测序技术由于技术限制而无法充分利用馆藏标本开展生命之树重建研究。新兴的标本组学是近年来基于二代测序技术发展起来的获取标本材料中基因组DNA的技术,这种技术通过对短片段测序和生物信息学方法拼接获得基因组DNA序列,因此可以充分利用馆藏标本材料,结合浅层测序和靶序列捕获能获得包括nrITS、叶绿体基因组、线粒体基因组以及单拷贝核基因等序列,从而满足系统发生重建的需要,且有着经济、省时、高效、准确的优势。新兴标本组学的应用将加速生命之树重建、DNA条形码、物种保护和资源可持续利用等方面的研究。

Dendrology is a branch of biology,dealing with the characteristics of woody plants;and phylogeny is the basis of dendrology.Common limiting factors in phylogenetic studies include inadequate species sampling and the availability of sufficient sequence data.The application of new approaches may broaden the range of materials to be utilized and thereby improve the resolution of phylogenies,thus advancing dendrological studies to higher levels.Herbaria preserve specimens that are the permanent vouchers for species;they comprise an important resource bank,storing information on morphology,distribution,ecology and phenology,and also plant materials.Herbarium specimens contain deoxyribonucleic acid(DNA)sequences fragmented due to degradation and oxidization during specimen preparation and preservation.As such,Sanger sequencing cannot make full use of herbarium specimens in phylogenetic studies due to these limitations.This study introduces a novel method referred to as herbariomics,in which DNA sequences(i.e.,nrITS,plastomes,mitomes and single-copy nuclear genes)can be obtained from herbarium specimens by using next-generation sequencing and bioinformatics methodologie.Herbariomics enable low-cost,time-saving,highly efficient,and accurate dendrological research.Its application is likely to accelerate research associated with reconstructing the Tree of Life,DNA barcoding,species conservation,and the sustainable utilization of trees.