Song Xixia, Liu Dandan, Yao Yubo, Tang Lili, Cheng Lili, Yang Lie, Jiang Zhongjuan, Kang Qinghua, Chen Si, Ru Jiarong, Zhang Lili, Wu Guangwen, Yuan Hongmei
Heilongjiang Academy of Agricultural Sciences, Harbin, 150000, China.
Heilongjiang University, Harbin, 150000, China.
BMC Genomics. 2025 Mar 31;26(1):315. doi: 10.1186/s12864-025-11481-5.
Cinnamoyl-CoA reductase (CCR) is the first important and committed enzyme in the monolignol synthesis branch of the lignin biosynthesis (LB) pathway, catalyzing the conversion of cinnamoyl-CoAs to cinnamaldehydes and is crucial for the growth of Linum usitatissimum (flax), an important fiber crop. However, little information is available about CCR in flax (Linum usitatissimum L.).
In this study, we conducted a genome-wide analysis of the CCR gene family and identified a total of 22 CCR genes. The 22 CCR genes were distributed across 9 chromosomes, designated LuCCR1-LuCCR22. Multiple sequence alignment and conserved motif analyses revealed that LuCCR7/13/15/20 harbor completely conserved NADP-specific, NAD(P)-binding, and CCR signature motifs. Furthermore, each of these LuCCRs is encoded by 5 exons separated by 4 introns, a characteristic feature of functional CCRs. Phylogenetic analysis grouped LuCCRs into two clades, with LuCCR7/13/15/20 clustering with functional CCRs involved in LB in dicotyledonous plants. RNA-seq analysis indicated that LuCCR13/20 genes are highly expressed throughout all flax developmental stages, particularly in lignified tissues such as roots and stems, with increased expression during stem maturation. These findings suggest that LuCCR13/20 play crucial roles in the biosynthesis process of flax lignin. Additionally, LuCCR2/5/10/18 were upregulated under various types of abiotic stress, highlighting their potential roles in flax defense-related processes.
This study systematically analyzes the CCR gene family (CCRGF) of flax (Linum usitatissimum L.) at the genomic level for the first time, so as to select the whole members of the CCRGF of flax and to ascertain their potential roles in lignin synthesis. Therefore, in future work, we can target genetic modification of LuCCR13/20 to optimize the content of flax lignin. As such, this research establishes a theoretical foundation for studying LuCCR gene functions and offers a new perspective for cultivating low-lignin flax varieties.
肉桂酰辅酶A还原酶（CCR）是木质素生物合成（LB）途径中单木质醇合成分支的首个重要且关键的酶，催化肉桂酰辅酶A转化为肉桂醛，对重要纤维作物亚麻（Linum usitatissimum）的生长至关重要。然而，关于亚麻（Linum usitatissimum L.）中CCR的信息却很少。
在本研究中，我们对CCR基因家族进行了全基因组分析，共鉴定出22个CCR基因。这22个CCR基因分布在9条染色体上，命名为LuCCR1 - LuCCR22。多序列比对和保守基序分析表明，LuCCR7/13/15/20具有完全保守的NADP特异性、NAD(P)结合和CCR特征基序。此外，这些LuCCR中的每一个都由5个外显子和4个内含子分隔编码，这是功能性CCR的一个特征。系统发育分析将LuCCR分为两个进化枝，其中LuCCR7/13/15/20与双子叶植物中参与LB的功能性CCR聚类。RNA测序分析表明，LuCCR13/20基因在亚麻所有发育阶段均高度表达，特别是在根和茎等木质化组织中，在茎成熟过程中表达增加。这些发现表明，LuCCR13/20在亚麻木质素的生物合成过程中起关键作用。此外，LuCCR2/5/10/18在各种非生物胁迫下上调，突出了它们在亚麻防御相关过程中的潜在作用。
本研究首次在基因组水平上系统分析了亚麻（Linum usitatissimum L.）的CCR基因家族（CCRGF），以筛选出亚麻CCRGF的所有成员，并确定它们在木质素合成中的潜在作用。因此，在未来的工作中，我们可以针对LuCCR13/20进行基因改造，以优化亚麻木质素的含量。因此，本研究为研究LuCCR基因功能奠定了理论基础，并为培育低木质素亚麻品种提供了新的视角。
