Zinc Finger Protein5Is Required for the Control of Trichome Initiation by Acting Upstream ofZinc Finger Protein8in Arabidopsis

Zhongjing Zhou,Lili Sun,Hao Yu,Wanyan Xi,Shuijin Zhu,Yinbo Gan,Lijun An,Pierre Broun

doi:10.1104/pp.111.180281

Zhongjing Zhou, Lili Sun + Show 6 more

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https://doi.org/10.1104/pp.111.180281

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Journal: Plant Physiology	Publication Date: Jul 29, 2011
Citations: 108	License type: CC BY 4.0

Affiliation: Temasek Life Sciences Laboratory

Abstract

Arabidopsis (Arabidopsis thaliana) trichome development is a model system for studying cell development, cell differentiation, and the cell cycle. Our previous studies have shown that the GLABROUS INFLORESCENCE STEMS (GIS) family genes, GIS, GIS2, and ZINC FINGER PROTEIN8 (ZFP8), control shoot maturation and epidermal cell fate by integrating gibberellins (GAs) and cytokinin signaling in Arabidopsis. Here, we show that a new C2H2 zinc finger protein, ZFP5, plays an important role in controlling trichome cell development through GA signaling. Overexpression of ZFP5 results in the formation of ectopic trichomes on carpels and other inflorescence organs. zfp5 loss-of-function mutants exhibit a reduced number of trichomes on sepals, cauline leaves, paraclades, and main inflorescence stems in comparison with wild-type plants. More importantly, it is found that ZFP5 mediates the regulation of trichome initiation by GAs. These results are consistent with ZFP5 expression patterns and the regional influence of GA on trichome initiation. The molecular analyses suggest that ZFP5 functions upstream of GIS, GIS2, ZFP8, and the key trichome initiation regulators GLABROUS1 (GL1) and GL3. Using a steroid-inducible activation of ZFP5 and chromatin immunoprecipitation experiments, we further demonstrate that ZFP8 is the direct target of ZFP5 in controlling epidermal cell differentiation.

Highlights

Arabidopsis (Arabidopsis thaliana) trichome development is a model system for studying cell development, cell differentiation, and the cell cycle
In order to investigate whether the new C2H2 transcription factor, ZFP5, plays a role in trichome initiation, we created 35S:ZFP5 transgenic lines and found that they displayed an abnormally high density of trichomes on the second lateral branch (Fig. 1A) and inflorescence organs (Fig. 1B), which is similar to the phenotypes of 35S:GLABROUS INFLORESCENCE STEMS (GIS) and 35S:ZINC FINGER PROTEIN8 (ZFP8) (Gan et al, 2006, 2007b)
35S:ZFP5 plants displayed a number of phenotypic changes that we explained as heterochronic shifts in development

Summary

Introduction

Arabidopsis (Arabidopsis thaliana) trichome development is a model system for studying cell development, cell differentiation, and the cell cycle. The first report on the involvement of GA in trichome development comes from Chien and Sussex (1996), who showed that the application of GA to the glabrous GA deficiency mutant ga induces earlier trichome formation on the adaxial epidermis compared with the abaxial epidermis and that GA stimulates trichome formation This result was confirmed by Telfer et al (1997), who demonstrated the promotion of trichome production in Arabidopsis by GA and that GA regulated the abaxial trichome formation and phase change. GA and cytokinin signals are integrated by the C2H2 transcription factors GLABROUS INFLORESCENCE STEMS (GIS), GIS2, and ZINC FINGER PROTEIN8 (ZFP8), and they, in turn, collectively regulate GL1 expression (Gan et al, 2006, 2007a, 2007b; Ishida et al, 2008). We report that a new C2H2 transcription factor, ZFP5, plays a key role in regulating inflorescence trichome development by directly targeting ZFP8 expression through a GA signaling pathway

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