The draft genome of a wild barley genotype reveals its enrichment in genes related to biotic and abiotic stresses compared to cultivated barley

First author: Miao Liu; Affiliations: CSIRO Agriculture and Food (澳大利亚联邦科学与工业研究组织农业与食品研究所): St Lucia, Australia

Corresponding author: Chunji Liu

Wild barley (Hordeum spontaneum) is the progenitor of cultivated barley (H. vulgare) and provides a rich source of genetic variations for barley improvement. Currently, the genome sequences of wild barley and its differences with cultivated barley remain unclear. In this study, we report a high‐quality draft assembly of wild barley accession (AWCS276; henceforth named as WB1), which consists of 4.28 Gb genome and 36,395 high‐confidence protein coding genes. BUSCO analysis revealed that the assembly included full lengths of 95.3% of the 956 single‐copy plant genes, illustrating that the gene‐containing regions have been well‐assembled. By comparing with the genome of the cultivated genotype Morex, it is inferred that the WB1 genome contains more genes involved in resistance and tolerance to biotic and abiotic stresses. The presence of the numerous WB1‐specific genes indicates that, in addition to enhance allele diversity for genes already existing in the cultigen, exploiting the wild barley taxon in breeding should also allow the incorporation of novel genes. Furthermore, high levels of genetic variation in the pericentomeric regions were detected in chromosome 3H and 5H between the wild and cultivated genotypes, which may be the results of domestication. This H. spontaneum draft genome assembly will help to accelerate wild barley research and be an invaluable resource for barley improvement and comparative genomics research.

野生大麦是现代栽培种大麦的祖先，并且为大麦的遗传改良提供了丰富的遗传变异。目前，野生大麦的基因组序列以及其与栽培种大麦基因的差异还不清楚。本文中，作者报道了野生大卖的高质量参考基因组，大小约为4.28Gb，共注释到34395个蛋白编码基因。BUSCO评估显示该版本的组装结果包含956个单拷贝植物基因的95.3%，说明包含基因的基因组区域组装的质量比较好。通过与栽培种基因组的比较，作者发现野生大麦的基因组包含更多与生物和非生物胁迫抗性相关的基因。大量野生大麦特异基因的存在说明在育种时利用野生大麦不仅能够增强现有等位基因的多样性，同时还能结合很多现代栽培种没有的新基因。此外，在现代栽培种和野生大麦之间，作者在3H和5H染色体上的近着丝粒区域鉴定到了高水平的遗传变异，这有可能是驯化所导致的。本文所报道的野生大麦基因组将有助于野生大麦的研究，并且作为大麦育种改良和比较基因组学研究的珍贵遗传资源。

通讯：Chunji Liu (https://people.csiro.au/L/C/Chunji-Liu)

个人简介：1987-1991年，英国剑桥植物育种研究所，博士；1991-1993年，英国约翰英尼斯中心剑桥实验室，博士后。

研究方向：植物疾病抗性、谷物基因组结构及演化的研究。

doi: https://doi.org/10.1111/pbi.13210

Journal: Plant Biotechnology Journal

First Published: July 17, 2019