GhWIP2, a WIP zinc finger protein, suppresses cell expansion in Gerbera hybrida by mediating crosstalk between gibberellin, abscisic acid, and auxin

Abstract

Cell expansion is a key determinant for the final size and shape of plant organ, and is regulated by various phytohormones. Zinc finger proteins (ZFPs) consist of a superfamily involved in multiple aspects of organ morphogenesis. However, little is known about WIP-type ZFP function in phytohormone-mediated organ growth. Using reverse genetics, RNA-seq and phytohormone quantification, we elucidated the role of a new WIP-type ZFP from Gerbera hybrida, GhWIP2, in controlling organ growth via regulation of cell expansion. GhWIP2 localizes to the nucleus and acts as a transcriptional repressor. Constitutive overexpression of GhWIP2 (GhWIP2OE) in both Gerbera and Arabidopsis thaliana caused major developmental defects associated with cell expansion, including dwarfism, short petals, scapes, and petioles. Furthermore, GhWIP2OE plants were hypersensitive to GA, but not to ABA, and showed a reduction in endogenous GA and auxin, but not ABA concentrations. Consistent with these observations, RNA-seq analysis revealed that genes involved in GA and auxin signaling were down-regulated, while those involved in ABA signaling were up-regulated in GhWIP2OE plants. Our findings suggest that GhWIP2 acts as a transcriptional repressor, suppressing cell expansion during organ growth by modulating crosstalk between GA, ABA, and auxin.

An ETHYLENE INSENSITIVE3-LIKE1 Protein Directly Targets the GEG Promoter and Mediates Ethylene-Induced Ray Petal Elongation in Gerbera hybrida

“…Protoplasts were isolated from gerbera leaves as described previously (Ren et al, 2018). YFP-GhEIL1 [GhEIL1 fused to yellow fluorescence protein (YFP) driven by the CaMV35S promoter] and YFP empty vector (YFP driven by the CaMV35S promoter) were transfected into protoplasts.…”

“…The empty pBS vector (EV) was co-transformed with different reporters as no-interaction controls. Finally, following the above transformations, protoplast samples were incubated at 24-26°C overnight, then harvested and analyzed using the dual-luciferase reporter assay system with a VeritasTM Microplate Luminometer (Promega, Madison, WI, USA) (Yoo et al, 2007;Ren et al, 2018).…”

“…Previously, we reported that gibberellin (GA) and abscisic acid (ABA) regulate cell expansion of gerbera petals in an antagonistic manner (Li et al, 2015). GhWIP2, a WIP-type ZFP transcription factor (TF), which is activated by ABA and inhibited by GA, was found to be associated with cell expansion in gerbera (Ren et al, 2018). Another class of plant hormones, brassinosteroids (BRs), promotes petal growth by regulating cell expansion in gerbera.…”

Genome-wide analysis of gibberellin-dioxygenases genes in rice

“…Massive studies showed that GA is not only involved in regulating the process of plant growth and development alone, but also in coordination with other plant hormones to function. For example, the crosstalk between GA, ABA and auxin can regulate cell expansion during organ growth in Gerbera hybrida [16]. By mediating ABA and GA biosynthesis exogenous auxin represses seed germination in soybean [17].…”

GIBBERELLIN INSENSITIVE DWARF1 Plays an Important Role in the Growth Regulation of Dwarf Apple Rootstocks

“…Plant growth is also controlled by the regulation of different hormone signals, including auxin, brassinolide, and abscisic acid (Ren et al, 2018). During the petal elongation growth process, auxin promotes cell elongation and increases the number of cells in the petal basal region, regulating flower growth and development (Wang et al, 2017).…”