羊草染色体辨认体系的建立及其在探究羊草起源中的应用

羊草是禾本科赖草属多年生草本植物，广幅旱生草原的建群种、盐生草甸的优势种，也是我国重要乡土物种和优质牧草。羊草基础遗传学研究滞后、全基因组测序进展缓慢，迫切需要开展羊草细胞遗传学研究来补充测序研究的短板，并解决羊草基本基因组来源等一系列科学问题。本项目将通过低覆盖率测序、生物信息学分析、多色多次FISH、单拷贝序列FISH、比较染色体作图等技术手段，开展①筛选串联重复序列作为羊草染色体标记；②一次性精确辨认羊草全套28条染色体；③羊草染色体辨认图与小麦遗传连锁图的统一；④探索羊草多倍体基因组的起源等研究内容，达到建立羊草染色体辨认体系、建立羊草染色体与小麦遗传连锁群的联系、明确羊草倍性类型和基本基因组来源的目的。本项目的完成将增进对羊草基因组结构的了解，解决其多倍体基因组起源的问题，建立起的羊草现代细胞遗传学染色体精确辨认体系，将成为进一步研究羊草及其近缘种的系统进化关系的有力工具。

Leymus chinensis (Trin.) Tzvel., a perennial herb of the genus Leymus, is a constructive species in broad-spectrum dry grassland and a dominant species in the salt-producing meadow. It is also an important native species and high-quality pasture in China. However, the basic genetics research of Leymus chinensis lags behind and the whole genome sequencing goes slowly. It is urgently needed to carry out the cytogenetic research of Leymus chinensis to supplement the shortcomings of sequencing research and to solve a series of scientific problems, such as the origin of the basic genome of Leymus chinensis. Based on low coverage sequencing, bioinformatics analysis, multicolor FISH, single copy sequence FISH, comparative chromosome mapping and other techniques, this project will screen tandem repeats to get the chromosome specific probe in Leymus chinensis, distinguish the full set of 28 chromosomes with chromosome specific probes in one time, establish the integration of chromosome identification map of Leymus chinensis and genetic linkage map of wheat, and explore the origin of Leymus chinensis polyploid genome. This project will achieve the goal of establishing the precise chromosome identification system in Leymus chinensis, establishing the linkage between Leymus chinensis chromosome and wheat genetic linkage group, and clarifying the ploidy type and origin of basic genome in Leymus chinensis. This project will enhance the understanding of the genome structure of Leymus chinensis and solve the problem of the origin of its polyploid genome. The modern cytogenetic chromosome identification system of Leymus chinensis will be a powerful tool to further study the phylogenetic relationship of Leymus chinensis and its related species.