ERF4 affects fruit firmness through TPL4 by reducing ethylene production

Abstract

Summary The firmness of fleshy fruit crops has a significant effect on their quality, consumer preference, shelf life and transportability. In a combined quantitative trait locus and genome‐wide association studies study of apple fruit texture, we identified a mutation (C‐G) in the ethylene response factor‐associated amphiphilic repression (EAR) motif in the coding region of the apple ETHYLENE RESPONSE FACTOR4 (ERF4) gene. Chromatin immunoprecipitation sequencing showed that ERF4 binds to the promoter of ERF3, which is involved in regulation of ethylene biosynthesis. The EAR mutation in ERF4 results in reduced repression of ERF3 expression, which is turn promotes ethylene production and loss of fruit firmness. ERF4 acts as a transcriptional repressor whose activity is modulated by a TOPLESS co‐repressor 4 (TPL4)‐binding EAR repression motif. Biolayer interferometry analysis showed that the mutation in the EAR motif causes a reduction in the interaction with TPL4. Suppression of ERF4 or TPL4 promoted fruit ripening and ethylene production. Taken together, our results provide insights into how ERF4 allelic variation underlies an important fruit quality trait.

Ethylene increases the cold tolerance of apple via the MdERF1B–MdCIbHLH1 regulatory module

“…Low temperatures clearly induced the expression of both genes, with peak MdACS1 and MdACO1 transcription levels detected at 8 h (about 10‐fold) and 12 h (about 6‐fold), respectively, followed by a gradual decrease (Figure 2b). The following six TFs have been identified as important regulators associated with the ethylene synthesis: MdEIL1 (An et al ., 2018a), MdERF1 (Wang et al ., 2007), MdERF1B (Zhang et al ., 2018), MdERF2 (Wang et al ., 2007), MdERF3 (Li et al ., 2016), and MdERF4 (Hu et al ., 2020). As shown in Figure 2(b), cold stress treatment upregulated the transcription of MdEIL1 , MdERF1B , MdERF2 , and MdERF3 to varying degrees.…”

“…Because several ERF TFs can link ethylene production with stress responses (An et al ., 2018b; Hu et al ., 2020; Li et al ., 2016; Zhang and Huang, 2010), we further verified whether MdERF1B regulated ethylene production in apple. The expression levels of MdACO1 and MdERF3 were obviously higher in the MdERF1B‐OX calli than in the WT calli (Figure 7a).…”

Recent Advances in Phytohormone Regulation of Apple-Fruit Ripening

“…The existence of ERF with negative regulation might balance the speed of fruit ripening, which prevents the fruit from ripening too quickly, and is helpful for attracting animals to disperse seeds. In addition, MdERF4 binds to the MdERF3 promoter and represses its expression [29]. A mutation (C-G) was identified in the ethylene response factor-associated amphiphilic repression (EAR) motif of the MdERF4 coding region.…”

“…A mutation (C-G) was identified in the ethylene response factor-associated amphiphilic repression (EAR) motif of the MdERF4 coding region. The EAR mutation of MdERF4 leads to reduced inhibition of MdERF3 expression, which in turn promotes ethylene biosynthesis [29].…”

SlTPL1 Silencing Induces Facultative Parthenocarpy in Tomato

“…This results revealed that all 13 genes displayed the same trend, and the Pearson correlation coefficient between RNA-seq and qRT-PCR data was 0.92 (P < 0.0001), indicating that the RNA-seq was reliable (Supplementary Figure 4). The TPL/TPR family of co-repressors functions as a central regulatory hub regulating all nine phytohormone pathways and controlling plant development, including meristem maintenance, fruit ripening, and anthocyanin accumulation (Gallavotti et al, 2010;Fukazawa et al, 2014;Hao et al, 2014;Qu et al, 2019;Hu et al, 2020). As TPL proteins lack DNA-binding activity, they are incorporated into transcription complexes by interacting with transcription factors to repress gene expression in various processes (Causier et al, 2012(Causier et al, , 2014.…”