Key message: The trichome-related protein (TRP) is a novel transcription factor (TF) that negatively regulates trichome initiation-related TFs through gibberellin (GA) signaling. Abstract: Trichomes, which are outgrowths of leaf epidermal cells, provide the plant with a first line of defense against damage from herbivores and reduce transpiration. The initiation and development of trichomes are regulated by a network of positively or negatively regulating transcription factors (TFs). However, little information is currently available on transcriptional regulation related to trichome formation. Here, we report a novel TF Trichome-Related Protein (TRP) that was observed to negatively regulate the trichome initiation-related TFs through gibberellic acid (GA) signaling. ProTRP:GUS revealed that TRP was only expressed in the trichome. The TRP loss-of-function mutant (trp) had an increased number of trichomes on the flower, cauline leaves, and main inflorescence stems compared to the wild-type. In contrast, TRP overexpression lines (TRP-Ox) exhibited a decreased number of trichomes on cauline leaves and main inflorescence stem following treatment with exogenous GA. Moreover, the expressions of trichome initiation regulators (GIS, GIS2, ZFP8, GL1, and GL3) increased in trp plants but decreased in TRP-Ox lines after GA treatment. TRP was observed to physically interact with ZFP5, a C2H2 TF that controls trichome cell development through GA signaling, both in vivo and in vitro. Based on these results, we suggest that TRP functions upstream of the trichome initiation regulators and represses the binding of ZFP5 to the ZFP8 promoter.
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Acknowledgements This work was supported by a Grant (PJ011065) from the Next-Generation BioGreen 21 Program funded by the Rural Development Administration, Republic of Korea. SYK was supported by a Grant (NRF-2016R1A6A3A11930302) from the National Research Foundation, the Ministry of Science, Technology and Future Planning, Republic of Korea. This work was also partially supported by Korea University.
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- Arabidopsis thaliana
- Gibberellic acid signaling
- Transcription factor
ASJC Scopus subject areas
- Agronomy and Crop Science
- Plant Science