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Molecular Plant: 苦荞基因组的测序揭示芦丁的生物合成及耐逆机制
作者:   来源:中国科学院遗传与发育生物学研究所   发布者:尹海华   日期:2017-09-07   今日/总浏览:29/1504

中国科学院遗传与发育生物学研究所梁承志研究员联合山西农科院乔治军研究员及华南农业大学王俊教授共同发表了题为“The Tartary Buckwheat Genome Provides Insights into Rutin Biosynthesis and Abiotic Stress Tolerance”的文章,该团队首次获得了苦荞高质量的参考基因组489.3Mb序列,并注释了33366个蛋白编码基因。

该研究成果公布在Molecular Plant杂志上,山西农科院张丽君副研究员和梁承志研究组博士生李秀秀,工程师马滨、高强和博士生杜会龙为该论文共同第一作者。

苦荞是少有的药食两用作物之一,具有良好的经济价值和开发潜力。苦荞属于石竹目蓼科,起源于中国西南部,具有较高的耐铝、耐旱、耐寒等耐逆特性,适合于在高海拔干旱或土壤肥力不足的地区种植。苦荞籽粒具有很高的营养价值,蛋白含量高且富含人类不能合成的必须氨基酸,也含有多种维生素和矿物质,特别是苦荞种子含有大量的药用类黄酮化合物芦丁。苦荞面粉中由于不含有麸质蛋白,对于麸质敏感的人群是一种极佳的谷物替代品,近年来受到越来越多的欢迎。然而苦荞育种及加工存在瓶颈,限制了其产量的提高及大面积的种植推广。

本研究发现,苦荞在约六千万前经历了一次最近的独立全基因组复制事件,由此导致了基因组中很多耐逆相关基因的扩增和保留。基于比较基因组学和转录组学的研究鉴定了编码芦丁代谢途径上编码各类酶的基因及调控这些基因表达的MYB类转录因子。此外研究还发现苦荞中大量可能与植物耐铝、抗旱和耐寒相关的新基因,其产物包括一些转运蛋白以及相关的转录因子。本研究表明,苦荞的耐受高水平非生物胁迫的能力很可能是由于参与信号转导、膜转运和基因转录调控等相关基因家族的扩增引起的。此研究有助于把苦荞变成为一个研究耐逆的模式植物。一直以来,苦荞杂交育种在生产实践中具有较高难度,其主要原因是其花器官太小(约2mm)。此参考基因组的获得将有助于通过突变体筛选结合比较基因组研究来创制大花的苦荞,使杂交育种变成常规育种工作,从而尽快提高苦荞的产量,或是增加种子大小,使苦荞的加工变得容易,并消除苦荞的苦味因子(种子中的芦丁水解酶),从而促进苦荞产业的发展。

原文标题:

The Tartary Buckwheat Genome Provides Insights into Rutin Biosynthesis and Abiotic Stress Tolerance

Abstract:Tartary buckwheat (Fagopyrum tataricum) is an important pseudocereal crop that is strongly adapted to growth in adverse environments. Its gluten-free grain contains complete proteins with a well-balanced composition of essential amino acids, and is a rich source of beneficial phytochemicals that provide significant health benefits. Here we report a high-quality, chromosome-scale Tartary buckwheat genome sequence of 489.3 Mb that is assembled by combining whole genome shotgun sequencing of both Illumina short reads and single-molecule real time long reads, sequence tags of a large DNA insert fosmid library, Hi-C sequencing data and BioNano genome maps. We annotated 33 366 high confidence protein-coding genes based on expression evidence. Comparisons of the intra-genome with the sugar beet genome revealed an independent whole genome duplication that occurred in the buckwheat lineage after they have diverged from the common ancestor, which was not shared with rosids or asterids. The reference genome facilitated the identification of many new genes predicted to be involved in rutin biosynthesis and regulation, aluminum stress resistance, and in drought and cold stress responses. Our data suggests that Tartary buckwheat's ability to tolerate high levels of abiotic stress is attributed to the expansion of several gene families involved in signal transduction, gene regulation, and membrane transport. The availability of these genomic resources will facilitate the discovery of agronomically and nutritionally important genes and genetic improvement of Tartary buckwheat.


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