Growth-regulating factors (GRFs) are unique transcription factors in plants. GRFs can interact with SNH (SYT N-terminal homology) domains in GRF-interacting factor (GIF) proteins via the N-terminal QLQ (Gln, Leu, Gln) domain to form functional complexes and participate in the regulation of downstream gene expression. In this study, we systematically identified the GRF gene family and GIF gene family in wheat and its relatives comprising Triticum urartu, Triticum dicoccoides, and Aegilops tauschii. Thirty GRF gene members are present in wheat, which are distributed on 12 chromosomes and they have 2-5 protein-coding regions. They all contain QLQ and WRC (Trp, Arg, Cys) conserved domains. Wheat possesses only eight members of the GIF gene family, which are distributed on six chromosomes. All wheat GIF (TaGIF) proteins have highly conserved SNH and QG (Gln, Gly) domains. The wheat GRF (TaGRF) gene family has 13 pairs of segmental duplication genes and no tandem duplication genes; the TaGIF gene family has two pairs of segmental duplication genes and no tandem duplication genes. It is speculated that segmental duplication events may be the main reason for the amplification of TaGRF gene family and TaGIF gene family. Based on published transcriptome data and qRT-PCR results of 8 TaGRF genes and 4 TaGIF genes, all of the genes responded strongly to osmotic stress, and the expression levels of TaGRF21 and TaGIF5 were also significantly upregulated under drought and cold stress conditions. The results obtained in this study may facilitate further investigations of the functions of TaGRF genes and TaGIF genes in order to identify candidate genes for use in stress-resistant wheat breeding programs.

中文翻译：

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普通小麦生长调节因子（GRF）基因家族和GRF相互作用因子家族的全基因组鉴定和分析。

生长调节因子（GRF）是植物中独特的转录因子。GRF可以通过N末端QLQ（Gln，Leu，Gln）结构域与GRF相互作用因子（GIF）蛋白中的SNH（SYT N末端同源性）结构域相互作用，形成功能复合物并参与下游基因表达的调控。在这项研究中，我们系统地鉴定了小麦及其近亲中的GRF基因家族和GIF基因家族，其中包括小麦，黑麦和小麦粉。小麦中存在30个GRF基因成员，它们分布在12条染色体上，并具有2-5个蛋白质编码区。它们都包含QLQ和WRC（Trp，Arg，Cys）保守域。小麦仅具有GIF基因家族的八个成员，这些成员分布在六个染色体上。所有小麦GIF（TaGIF）蛋白均具有高度保守的SNH和QG（Gln，Gly）结构域。小麦GRF（TaGRF）基因家族有13对节段重复基因，没有串联重复基因。TaGIF基因家族有两对节段重复基因，没有串联重复基因。推测节段性复制事件可能是TaGRF基因家族和TaGIF基因家族扩增的主要原因。根据公开的转录组数据和8个TaGRF基因和4个TaGIF基因的qRT-PCR结果，所有这些基因均对渗透胁迫反应强烈，并且在干旱和寒冷胁迫条件下，TaGRF21和TaGIF5的表达水平也显着上调。