Tiller formation is a key agronomic determinant for grain yield in cereal crops. The modulation of this trait is controlled by transcriptional regulators and plant hormones, tightly regulated by external environmental conditions. While endogenous (genetics) and exogenous (environmental factors) triggers for tiller formation have mostly been investigated separately, it has remained elusive how they are integrated into the developmental program of this trait. The transcription factor INTERMEDIUM-C (INT-C), which is the barley ortholog of the maize domestication gene TEOSINTE BRANCHED1 (TB1) has a prominent role in regulating tiller bud outgrowth. Here we show that INT-C is expressed in tiller buds, required for bud growth arrest in response to shade. In contrast to wild type plants, int-c mutant plants are impaired in their shade response and do not stop tiller production after shading. Gene expression levels of INT-C are up-regulated under light-limiting growth conditions, and down-regulated after decapitation. Transcriptome analysis of wild-type and int-c buds under control and shading conditions identified target genes of INT-C that belong to auxin and gibberellin biosynthesis and signaling pathways. Our study identifies INT-C as integrator of the shade response into tiller formation, which is prerequisite for implementing shading responses in the breeding of cereal crops.

中文翻译：

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INTERMEDIUM-C介导大麦遮荫诱导的芽生长停滞

分iller形成是谷物作物谷物产量的关键农学决定因素。该特性的调节受转录调节剂和植物激素的控制，植物激素受到外部环境条件的严格控制。尽管对分till形成的内源性（遗传）和外源性（环境因素）触发因素大多进行了单独研究，但如何将其整合到该性状的发育程序中仍然难以捉摸。转录因子INTERMEDIUM-C（INT-C）是玉米驯化基因TEOSINTE BRANCHED1（TB1）的大麦直系同源基因，在调节分er芽的生长中具有重要作用。在这里，我们证明了INT-C在分er芽中表达，而芽分叉是遮蔽芽生长所必需的。与野生型植物相反 int-c突变植物的遮光反应受损，遮光后不会停止分till生产。INT-C的基因表达水平在光受限的生长条件下被上调，而在斩首后被下调。在控制和遮蔽条件下对野生型和int-c芽进行转录组分析，确定了INT-C的靶基因，这些基因属于生长素和赤霉素的生物合成和信号传导途径。我们的研究确定INT-C是分as形成过程中阴影响应的整合者，这是在谷物作物育种中实施阴影响应的前提。在控制和遮蔽条件下对野生型和int-c芽进行转录组分析，确定了INT-C的靶基因，这些基因属于生长素和赤霉素的生物合成和信号传导途径。我们的研究确定INT-C是分as形成过程中阴影响应的整合者，这是在谷物作物育种中实施阴影响应的前提。在控制和遮蔽条件下对野生型和int-c芽进行转录组分析，确定了INT-C的靶基因，这些基因属于生长素和赤霉素的生物合成和信号传导途径。我们的研究确定INT-C是分as形成过程中阴影响应的整合者，这是在谷物作物育种中实施阴影响应的前提。