A genome-wide analysis of the flax (Linum usitatissimum L.) dirigent protein family: from gene identification and evolution to differential regulation
A genome-wide analysis of the flax (Linum usitatissimum L.) dirigent protein family: from gene identification and evolution to differential regulation
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DOI：
10.1007/s11103-018-0725-x
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发表时间：
2018-05-01
影响因子：
5.1
通讯作者：
Hano, Christophe
中科院分区：
文献类型：
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作者：
Corbin, Cyrielle;Drouet, Samantha;Hano, Christophe
在8-8‘-木脂素生物合成研究中，通过立体选择性偶联反应从E-松柏醇合成(+)-或(-)-松脂醇，发现了二聚体蛋白(DIRS)。DIRS还参与或可能参与萜类、烯丙基/丙烯基酚木脂素、蕨类和木质素的生物合成。DIRS在包括亚麻在内的不同维管束植物中都有很大的多基因家族，其中大部分功能尚不清楚。DIR研究通常集中在一小部分基因和生化/生理功能的鉴定上。在这里，对预测的亚麻DIR 44人多基因家族进行了全基因组分析和表征，该物种是8-8‘连接的次异落叶松脂醇衍生的木脂素低聚物的丰富的天然谷物来源。所有预测的DIR序列，包括它们的启动子，与它们的公共基因表达数据集一起被分析。通过定量聚合酶链式反应和对DIR基因表达的聚类分析，检测所选DIR基因的表达模式。这些分析进一步暗示了特定的DIR在种皮中(-)-松脂醇的形成中所起的作用，以及(+)-松脂醇在营养器官和/或对胁迫的特定反应中的作用。系统发育和基因表达分析将亚麻DIR分为六个不同的簇，并发现了新的簇特有的基序。我们认为，这些发现可以作为进一步系统地确定DIRS功能的基础，即除了已知的在亚麻和其他物种中木脂素生物合成的功能之外。鉴于亚麻DIR家族的差异表达谱和可诱导性，我们暂时提出了一些未知功能的DIR基因可能参与次生细胞壁生物合成和植物防御的不同方面。
Dirigent proteins (DIRs) were discovered during 8-8' lignan biosynthesis studies, through identification of stereoselective coupling to afford either (+)- or (-)-pinoresinols from E-coniferyl alcohol. DIRs are also involved or potentially involved in terpenoid, allyl/propenyl phenol lignan, pterocarpan and lignin biosynthesis. DIRs have very large multigene families in different vascular plants including flax, with most still of unknown function. DIR studies typically focus on a small subset of genes and identification of biochemical/physiological functions. Herein, a genome-wide analysis and characterization of the predicted flax DIR 44-membered multigene family was performed, this species being a rich natural grain source of 8-8' linked secoisolariciresinol-derived lignan oligomers. All predicted DIR sequences, including their promoters, were analyzed together with their public gene expression datasets. Expression patterns of selected DIRs were examined using qPCR, as well as through clustering analysis of DIR gene expression. These analyses further implicated roles for specific DIRs in (-)-pinoresinol formation in seed-coats, as well as (+)-pinoresinol in vegetative organs and/or specific responses to stress. Phylogeny and gene expression analysis segregated flax DIRs into six distinct clusters with new cluster-specific motifs identified. We propose that these findings can serve as a foundation to further systematically determine functions of DIRs, i.e. other than those already known in lignan biosynthesis in flax and other species. Given the differential expression profiles and inducibility of the flax DIR family, we provisionally propose that some DIR genes of unknown function could be involved in different aspects of secondary cell wall biosynthesis and plant defense.