PIN proteins are auxin export carriers that direct intercellular auxin flow and in turn regulate many aspects of plant growth and development including responses to environmental changes. The Arabidopsis R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 regulate terminal divisions during stomatal development, as well as female reproductive development and stress responses. Here we show that FLP and MYB88 act redundantly but differentially in regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots. On the one hand, FLP is involved in responses to gravity stimulation in primary roots, whereas on the other, FLP and MYB88 function complementarily in establishing the gravitropic set-point angles of lateral roots. Our results support a model in which FLP and MYB88 expression specifically determines the temporal-spatial patterns of PIN3 and PIN7 transcription that are closely associated with their preferential functions during root responses to gravity.

中文翻译：

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拟南芥根引力作用期间四个LIPS和MYB88对PIN基因的转录调控。

PIN蛋白是植物生长素的输出载体，可指导细胞间植物生长素的流动，进而调节植物生长和发育的许多方面，包括对环境变化的响应。拟南芥R2R3-MYB转录因子FOUR LIPS（FLP）及其旁系同源物MYB88调节气孔发育，雌性生殖发育和应激反应期间的末端分裂。在这里，我们显示FLP和MYB88在调节主根和侧根重力感应细胞中PIN3和PIN7的转录中起着冗余但有差异的作用。一方面，FLP参与了初生根对重力刺激的响应，而另一方面，FLP和MYB88在建立侧根的重力定点角时起互补作用。