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

Abstract

Petal morphogenesis has a profound influence on the quality of ornamental flowers. Most current research on petal development focuses on the early developmental stage, and little is known about the late developmental stage. Previously, it was reported that the GEG gene [a gerbera homolog of the gibberellin-stimulated transcript 1 (GAST1) from tomato] negatively regulates ray petal growth during the late stage of development by inhibiting longitudinal cell expansion. To explore the molecular mechanisms of the role of GEG in petal growth inhibition, an ethylene insensitive 3-like 1 (EIL1) protein was identified from a Gerbera hybrida cDNA library by yeast one-hybrid screening. Direct binding between GhEIL1 and the GEG promoter was confirmed by electrophoretic mobility shift and dual-luciferase assays. The expression profiles of GhEIL1 and GEG were correlated during petal development, while a transient transformation assay suggested that GhEIL1 regulates GEG expression and may be involved in the inhibition of ray petal elongation and cell elongation. To study the effect of ethylene on ray petal growth, a hormone treatment assay was performed in detached ray petals. The results showed that petal elongation is limited and promoted by ACC and 1-MCP, respectively, and the expression of GhEIL1 and GEG is regulated and coordinated during this process. Taken together, our research suggests that GhEIL1 forms part of the ethylene signaling pathway and activates GEG to regulate ray petal growth during the late developmental stage in G. hybrida.

Genome-Wide Comprehensive Analysis of the GASA Gene Family in Populus

“…The expression of the GASA gene family was strongly inhibited or induced by gibberellin (Figure 7). It has been reported that the GASA gene family was involved in seed germination, shoot and stem elongation, lateral root formation, flowering and flower development, fruit development, and ripening [15][16][17][18][19][21][22][23][24][25]28]. PeuGASAs were also induced or inhibited by EBR, ABA, SA, and MeJA, indicating that GASAs might be extensively involved in the complex plant hormonal signal transduction network [26].…”

“…AtGASA5 delayed flowering time by enhancing the expression of FLC and repressing the expression of FT and LEAFY [17]. GhGEG, a gene from the GASA gene family in Gerbera hybrida, was directly transcriptional activated by GhMIF and GhEIL1 to inhibit the ray petal elongation and cell elongation during petal development [21,22]. AtGASA4 regulated the differentiation and development of flower development meristem and increases the seed size and yield of Arabidopsis.…”

GhGASA10–1 promotes the cell elongation in fiber development through the phytohormones IAA-induced

“…GAs are among the universal plant phytohormones that play a crucial role in the growth and development processes, including germination, stem elongation, photosynthesis, flowering, and seed development, while GASA -like genes possess a key role in GAs signaling pathway [ 12 , 22 , 23 ] in different plants viz. gerbera [ 24 ], and maize [ 10 ]. Some GASA genes are regulated by other hormones, as RSI1 was regulated by IAA [ 25 ], and OsGSR1/2 was regulated by GA3 [ 26 ].…”

14-3-3 Proteins Are Involved in BR-Induced Ray Petal Elongation in Gerbera hybrida

“…Functional analysis of GhCYC proteins revealed redundant functions of GhCYC2, GhCYC3 and GhCYC4 in regulating ray floret identity and in promoting petal development ( Juntheikki-Palovaara et al, 2014 ). Various hormones (gibberellin, abscisic acid, ethylene, and BRs) are involved in the regulation of late-stage petal development in gerbera ( Zhang et al, 2012 ; Li et al, 2015 ; Han et al, 2017 ; Huang et al, 2017 , 2020 ; Ren et al, 2018 ). Li et al (2015) found that GA 3 stimulates petal elongation in gerbera, while ABA inhibits it.…”