Siberian Branch of the Russian Academy of Sciences, Institute of Cytology and Genetics, Lavrentjeva Ave. 10, Novosibirsk, 630090, Russia.
N.I. Vavilov All-Russian Research Institute of Plant Genetic Resources (VIR), Bolshaya Morskaya Str., 42-44, St. Petersburg, 190000, Russia.
BMC Plant Biol. 2019 Feb 15;19(Suppl 1):50. doi: 10.1186/s12870-019-1639-8.
Myc-like regulatory factors carrying the basic helix-loop-helix (bHLH) domain belong to a large superfamily of transcriptional factors (TFs) present in all eukaryotic kingdoms. In plants, the representatives of this superfamily regulate diverse biological processes including growth and development as well as response to various stresses. As members of the regulatory MBW complexes, they participate in biosynthesis of flavonoids. In wheat, only one member (TaMyc1) of the Myc-like TFs family has been studied, while structural and functional organization of further members remained uncharacterized. From two Myc-subfamilies described recently in the genomes of Triticeae tribe species, we investigated thoroughly the members of the subfamily I which includes the TaMyc1 gene.
Comparison of the promoter regions of the Myc subfamily I members in wheat suggested their division into two groups (likely homoeologous sets): TaMyc-1 (TaMyc-A1/TaMyc1, TaMyc-B1, TaMyc-D1) and TaMyc-2 (TaMyc-A2 and TaMyc-D2). It was demonstrated that the TaMyc-D1 copy has lost its functionality due to the frame shift mutation. The study of functional features of the other four copies suggested some of them to be involved in the biosynthesis of anthocyanins. In particular, TaMyc-B1 is assumed to be a co-regulator of the gene TaC1-A1 (encoding R2R3-Myb factor) in the MBW regulatory complex activating anthocyanin synthesis in wheat coleoptile. The mRNA levels of the TaMyc-A1, TaMyc-B1, TaMyc-A2 and TaMyc-D2 genes increased significantly in wheat seedlings exposed to osmotic stress. Salinity stress induced expression of TaMyc-B1 and TaMyc-A2, while TaMyc-A1 was repressed.
The features of the structural and functional organization of the members of subfamily I of Myc-like TFs in wheat were determined. Myc-like co-regulator (TaMyc-B1) of anthocyanin synthesis in wheat coleoptile was described for the first time. The Myc-encoding genes presumably involved in response to drought and salinity were determined in wheat. The results obtained are important for further manipulations with Myc genes, aimed on increasing wheat adaptability.
具有碱性螺旋-环-螺旋（bHLH）结构域的 My 类调节因子属于转录因子（TFs）的一个超大家族，存在于所有真核生物界。在植物中，该超家族的代表调节多种生物过程，包括生长和发育以及对各种胁迫的反应。作为调节 MBW 复合物的成员，它们参与类黄酮的生物合成。在小麦中，只有 My 类 TF 家族的一个成员（TaMyc1）被研究过，而进一步成员的结构和功能组织仍然没有被描述。从最近在三叶草族物种基因组中描述的两个 My 亚家族中，我们深入研究了包括 TaMyc1 基因在内的 I 亚家族的成员。
对小麦 My 亚家族 I 成员启动子区域的比较表明，它们分为两组（可能是同源组）：TaMyc-1（TaMyc-A1/TaMyc1、TaMyc-B1、TaMyc-D1）和 TaMyc-2（TaMyc-A2 和 TaMyc-D2）。证明 TaMyc-D1 拷贝由于移码突变而失去了功能。对其他四个拷贝的功能特征的研究表明，其中一些拷贝参与了花青素的生物合成。特别是，TaMyc-B1 被认为是 MBW 调节复合物中 TaC1-A1（编码 R2R3-Myb 因子）基因的共调节因子，在小麦幼茎中激活花青素的合成。在渗透胁迫下，小麦幼苗中 TaMyc-A1、TaMyc-B1、TaMyc-A2 和 TaMyc-D2 基因的 mRNA 水平显著增加。盐胁迫诱导 TaMyc-B1 和 TaMyc-A2 的表达，而 TaMyc-A1 则受到抑制。
确定了小麦 My 类 TF 亚家族 I 成员的结构和功能组织特征。描述了小麦幼茎中花青素合成的 My 类共调节因子（TaMyc-B1）。在小麦中确定了可能参与干旱和盐胁迫反应的 Myc 编码基因。获得的结果对于进一步操纵 Myc 基因以提高小麦适应性非常重要。
