Large-Scale Identification of Gibberellin-Related Transcription Factors Defines Group VII ETHYLENE RESPONSE FACTORS as Functional DELLA Partners

Abstract

DELLA proteins are the master negative regulators in gibberellin (GA) signaling acting in the nucleus as transcriptional regulators. The current view of DELLA action indicates that their activity relies on the physical interaction with transcription factors (TFs). Therefore, the identification of TFs through which DELLAs regulate GA responses is key to understanding these responses from a mechanistic point of view. Here, we have determined the TF interactome of the Arabidopsis (Arabidopsis thaliana) DELLA protein GIBBERELLIN INSENSITIVE and screened a collection of conditional TF overexpressors in search of those that alter GA sensitivity. As a result, we have found RELATED TO APETALA2.3, an ethylene-induced TF belonging to the group VII ETHYLENE RESPONSE FACTOR of the APETALA2/ethylene responsive element binding protein superfamily, as a DELLA interactor with physiological relevance in the context of apical hook development. The combination of transactivation assays and chromatin immunoprecipitation indicates that the interaction with GIBBERELLIN INSENSITIVE impairs the activity of RELATED TO APETALA2.3 on the target promoters. This mechanism represents a unique node in the cross regulation between the GA and ethylene signaling pathways controlling differential growth during apical hook development.

Transcriptomic Analysis Implies That GA Regulates Sex Expression via Ethylene-Dependent and Ethylene-Independent Pathways in Cucumber (Cucumis sativus L.)

“…Given that the DELLA proteins are central repressors of GA responses (Sun, 2010, 2011; Plackett et al, 2014), and accumulating evidence suggested that DELLA proteins play important roles in ethylene-mediated plant growth and development processes through interactions with some regulatory factors in ethylene signaling pathway, such as CTR1 (CONSTITUTIVE TRIPLE RESPONSE1), EIN3/EIL1 (ETHYLENE INSENSITIVE 3/EIN3-LIKE 1), RAP 2.3 (RELATED TO APETALA 2.3), and ERF11 (ETHYLENE RESPONSE FACTOR 11) (Achard et al, 2003, 2007; Pierik et al, 2009; An et al, 2012; Luo et al, 2013; Marín-de la Rosa et al, 2014; Zhou et al, 2016). Therefore, we proposed that DELLA proteins may be involved in the sex differentiation of cucumber coupled with GA and ethylene in a collaborative regulation at the protein level, since the expressions of four DELLA homologs in cucumber, CsGAIP, CsGAI1, CsGAI2 , and CsGAI3 (Zhang et al, 2014a), had no change after GA 3 treatment (Supplementary Tables S1 and S2).…”

Emerging role of the plant ERF transcription factors in coordinating wound defense responses and repair

“…2). Despite this family-specific motif, ERF114 and ERF115 appear to not be the only ERF transcription factors to heterodimerize with GRAS proteins; the DELLA protein GAI was shown to interact with the ERF transcription factor RAP2.3, and, in doing so, GAI impairs the transcriptional activity of RAP2.3 on its target promoters (Marín-de la Rosa et al, 2014). Similarly, in a study on chitin-induced transcription factors ERF5 was shown to interact with SCL13.…”

Gibberellins negatively modulate ovule number in plants

“…DELLA proteins lack a canonical DNA-binding domain and, thus, mediate transcriptional regulation of target genes involved in the GA response throughout the direct physical interaction with transcriptional factors (TFs) and other regulatory proteins (Vera-Sirera et al, 2015;Daviere and Achard, 2016). The list of potential DELLA interactors has increased rapidly over the past few years, providing direct evidence of the mechanism of crosstalk between GAs and other hormones and environmental clues to modulate plant growth (Marin-de la Rosa et al, 2014Rosa et al, , 2015Daviere and Achard, 2016).…”