Key message

Microarray and genetic analyses reveal that ZTL induces the expression of genes related to auxin synthesis, thereby promoting hypocotyl elongation.

Abstract

ZTL is a blue-light receptor that possesses a light–oxygen–voltage-sensing (LOV) domain, an F-box motif, and a kelch repeat domain. ZTL promotes hypocotyl elongation under high temperature (28 °C) in Arabidopsis thaliana; however, the mechanism of this regulation is unknown. Here, we divided seedlings into hypocotyls and upper aerial parts, and performed microarray analyses. In hypocotyl, 1062 genes were down-regulated in ztl mutants (ztl-3 and ztl-105) compared with wild type; some of these genes encoded enzymes involved in cell wall modification, consistent with reduced hypocotyl elongation. In upper aerial parts, 1038 genes were down-regulated in the ztl mutants compared with wild type; these included genes involved in auxin synthesis and auxin response. Furthermore, the expression of the PHYTOCHROME INTERACTING FACTOR 4 (PIF4) gene, which encodes a transcription factor known to positively regulate YUCCA genes (YUCs), was also decreased in the ztl mutants. Genetic analysis revealed that overexpression of PIF4 and YUC8 could restore the suppressed hypocotyl length in the ztl mutants. Our results suggest that ZTL induces expression of YUC8 via PIF4 in upper aerial parts and promotes hypocotyl elongation.

中文翻译：

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ZEITLUPE增强拟南芥幼苗上部地上部分PIF4和YUC8表达正向调节下胚轴伸长

关键信息

微阵列和遗传分析表明， ZTL 诱导与生长素合成相关的基因表达，从而促进下胚轴伸长。

抽象的

ZTL 是一种蓝光受体，具有光-氧-电压感应 (LOV) 结构域、F-box 基序和 kelch 重复结构域。ZTL促进拟南芥高温（28℃）下胚轴伸长；然而，这种调节的机制尚不清楚。在这里，我们将幼苗分为下胚轴和上部地上部分，并进行微阵列分析。在下胚轴中，与野生型相比，ztl突变体（ztl-3和ztl-105 ）中有1062个基因下调；其中一些基因编码参与细胞壁修饰的酶，这与下胚轴伸长减少一致。在上部地上部分，1038 个基因在ztl中被下调突变体与野生型相比；这些包括参与生长素合成和生长素反应的基因。此外，编码已知正调节YUCCA基因 ( YUC s) 的转录因子的PHYTOCHROME INTERACTING FACTOR 4 ( PIF4 ) 基因的表达在ztl突变体中也降低了。遗传分析表明，PIF4和YUC8的过表达可以恢复ztl突变体中被抑制的下胚轴长度。我们的结果表明ZTL通过PIF4在上部地上部分诱导YUC8的表达并促进下胚轴伸长。