Global Identification of DELLA Target Genes during Arabidopsis Flower Development

Hou, Xue‐Long; Hu, Wenwei; Shen, Lisha; Lee, Li Yen Candy; Tao, Zhen; Han, Jin-Hua; Yu, Hao

doi:10.1104/pp.108.121301

Cited by 94 publications

(75 citation statements)

References 103 publications

(163 reference statements)

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“…ROXY2, which interacts with TGA9 and TGA10 proteins in yeast and in planta, functions redundantly together with ROXY1 in anther development and microspore formation (Xing and Zachgo, 2008;Murmu et al, 2010). ROXY4 is a target gene up-regulated by DELLA and participates in GA signaling and floral organ development (Hou et al, 2008). ROXY19 is known to function in pathogen defense (Ndamukong et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

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The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Gutsche

Zachgo

2011

Plant Physiology

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Glutaredoxins (GRXs) are small, ubiquitous, glutathione-dependent oxidoreductases that participate in redox-regulated processes associated with stress responses. Recently, GRXs have been shown to exert crucial functions during flower developmental processes. GRXs modulate their target protein activities by the reduction of protein disulfide bonds or deglutathionylation reactions. The Arabidopsis (Arabidopsis thaliana) GRX ROXY1 participates in petal primordia initiation and further petal morphogenesis. ROXY1 belongs to a land plant-specific class of GRXs with a CC-type active site motif, deviating from the ubiquitously occurring CPYC and CGFS GRX classes. ROXY1 was previously shown to interact with floral TGA transcription factors in the nucleus, and this interaction is a prerequisite for ROXY1 to exert its activity required for Arabidopsis petal development. Deletion analysis further identified the importance of the ROXY1 C terminus for the ROXY1/ TGA protein interactions and for the ROXY1 function in petal development. Here, by dissecting the ROXY1 C terminus, an a-helical L**LL motif immediately adjacent to the ROXY1 C-terminal eight amino acids was identified that is essential for the interaction with TGA transcription factors and crucial for the ROXY1 function in planta. Similar to the a-helical L**LL motifs binding to transcriptional coactivators with liganded nuclear receptors in animals, a hydrophobic face formed by the conserved leucines in the L**LL motif of ROXY1 possibly mediates the interaction with TGA transcription factors. Thus, the a-helical L**LL sequence is a conserved protein-protein interaction motif in both animals and plants. Furthermore, two separate TGA domains were identified by deletion experiments as being essential for mediating TGA protein interactions with ROXYs.

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Section: Discussionmentioning

confidence: 99%

“…ROXY1 and its closest homolog ROXY2 act redundantly during anther development and microspore formation (Xing and Zachgo, 2008). The other two CC-type GRX genes with known functions, ROXY19 (originally named GRX480) and ROXY4, participate in pathogen defense responses and GA signaling in Arabidopsis, respectively (Ndamukong et al, 2007;Hou et al, 2008).…”

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confidence: 99%

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Gutsche

Zachgo

2011

Plant Physiology

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“…The importance of the C terminus is further highlighted by the observation that the closest ROXY1/2 homologs from rice (Oryza sativa), Os ROXY1/2, also share this AI/LWL motif and can complement the roxy1-2 mutant . ROXY4, one of the GRXs that we found to complement roxy1-2, has been recently shown to participate in GA signaling and is a target gene upregulated by DELLA (Hou et al, 2008). However, if expressed under the control of ROXY1 endogenous regulatory sequences, it exerts a ROXY1-like function in petal development.…”

Section: Roxy1 Interacts With Tga Transcription Factorsmentioning

confidence: 91%

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

et al. 2009

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Glutaredoxins (GRXs) have thus far been associated mainly with redox-regulated processes participating in stress responses. However, ROXY1, encoding a GRX, has recently been shown to regulate petal primorida initiation and further petal morphogenesis in Arabidopsis thaliana. ROXY1 belongs to a land plant-specific class of GRXs that has a CC-type active site motif, which deviates from ubiquitously occurring CPYC and CGFS GRXs. Expression studies of yellow fluorescent protein-ROXY1 fusion genes driven by the cauliflower mosaic virus 35S promoter reveal a nucleocytoplasmic distribution of ROXY1. We demonstrate that nuclear localization of ROXY1 is indispensable and thus crucial for its activity in flower development. Yeast two-hybrid screens identified TGA transcription factors as interacting proteins, which was confirmed by bimolecular fluorescence complementation experiments showing their nuclear interaction in planta. Overlapping expression patterns of ROXY1 and TGA genes during flower development demonstrate that ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. Deletion analysis of ROXY1 demonstrates the importance of the C terminus for its functionality and for mediating ROXY1/TGA protein interactions. Phenotypic analysis of the roxy1-2 pan double mutant and an engineered chimeric repressor mutant from PERIANTHIA (PAN), a floral TGA gene, supports a dual role of ROXY1 in petal development. Together, our results show that the ROXY1 protein functions in the nucleus, likely by modifying PAN posttranslationally and thereby regulating its activity in petal primordia initiation. Additionally, ROXY1 affects later petal morphogenesis, probably by modulating other TGA factors that might act redundantly during differentiation of second whorl organs.

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“…STU is downregulated by RGA in the GA signaling pathway We performed a microarray analysis to identify immediate targets of RGA in Arabidopsis flower development (Hou et al, 2008) and selected STU (At2g16750) from a list of genes whose expression were altered by the induced RGA activity. To understand further the regulation of STU expression in the GA signaling pathway, we examined its expression in seedlings of various mutant backgrounds (Fig.…”

Section: Resultsmentioning

confidence: 99%

STUNTEDmediates the control of cell proliferation by GA inArabidopsis

et al. 2012

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Gibberellins (GA) are an important family of plant growth regulators, which are essential for many aspects of plant growth and development. In the GA signaling pathway, the action of GA is opposed by a group of DELLA family repressors, such as RGA. Although the mechanisms of action of the DELLA proteins have been studied in great detail, the effectors that act downstream of DELLA proteins and bring about GA-responsive growth and development remain largely unknown. In this study, we have characterized STUNTED (STU), a receptor-like cytoplasmic kinase (RLCK) VI family gene, which is ubiquitously detectable in all the tissues examined. RGA activity and GA signaling specifically mediate the levels of STU transcripts in shoot apices that contain actively dividing cells. stu-1 loss-of-function mutants exhibit retarded growth in many aspects of plant development. During the vegetative phase, stu-1 seedlings develop smaller leaves and shorter roots than wild-type seedlings, while during the reproductive phase, stu-1 exhibits delayed floral transition and lower fertility. The reduced stature of stu-1 partly results from a reduction in cell proliferation. Furthermore, we present evidence that STU serves as an important regulator mediating the control of cell proliferation by GA possibly through two cyclin-dependent kinase inhibitors, SIM and SMR1. Taken together, our results suggest that STU acts downstream of RGA and promotes cell proliferation in the GA pathway.

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Global Identification of DELLA Target Genes during Arabidopsis Flower Development

Cited by 94 publications

References 103 publications

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

Nuclear Activity of ROXY1, a Glutaredoxin Interacting with TGA Factors, Is Required for Petal Development inArabidopsis thaliana

STUNTEDmediates the control of cell proliferation by GA inArabidopsis

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