EAR motif mutation of rice OsERF3 alters the regulation of ethylene biosynthesis and drought tolerance

Abstract

OsERF3 is a transcriptional repressor with an ethylene-responsive element-binding factor-associated amphiphilic repression (EAR) motif (F/LDLNxxP), which transcriptionally represses the ethylene emission and drought tolerance in rice. However, its molecular mechanism to explore repression function remains unknown. Here, we first revealed that the expression of OsERF3 was induced by drought, salt, ACC and ABA treatment. In addition, it showed a higher expression level in the root and sheath than that in the leaf. Then, we generated transgenic rice overexpressing full-length OsERF3 (OE) and its mutation of EAR motif with the A 680/C substitution (mEAR), respectively. The physiological analyses showed that mEAR lines showed better drought tolerance and more ethylene emission compared with those of OE lines and wild type plants. Consistent with our previous research, the expression of ethylene synthesis genes, including ACO2, ACS2, and ACS6 was down-regulated in OE lines. However, the repression of OsERF3 was eliminated in mEAR lines. Specifically, ACS2 was up-regulated in mEAR lines compared with that in OE lines and WT plants, suggesting that the Leu/Ala substitution within the EAR motif resulted in loss of repression of OsERF3. Thus, our data reveal that the EAR motif is required for OsERF3 to transcriptionally regulate the ethylene synthesis and drought tolerance in rice, providing new insight to the roles of ethylene-response factor proteins in regulating ethylene biosynthesis and stress response.

Ethylene Signaling in Rice and Arabidopsis: Conserved and Diverged Aspects

“…OsEATB (ERF PROTEIN ASSOCIATED WITH TILLERING AND PANICLE BRANCHING) downregulated by ethylene sets a limit to ethylene-induced gibberellin responsiveness during the internode elongation process (Qi et al, 2011). OsDERF1 directly interacts with the GCC-box in the promoters of ERF repressors OsERF3 and OsAP2-39 to modulate drought tolerance by suppressing ethylene synthesis (Wan et al, 2011;Zhang et al, 2013).…”

Banana Transcription Factor MaERF11 Recruits Histone Deacetylase MaHDA1 and Represses the Expression of MaACO1 and Expansins during Fruit Ripening

“…In kiwifruit, AdERF9 suppressed activity of the AdXET5 promoter involved in regulating fruit ripening (Yin et al, 2010). Furthermore, mutations or deletions of the EAR motif resulted in partial or complete loss of repression activities in various EAR motif-containing proteins (Shyu et al, 2012;Zhang et al, 2013). In Arabidopsis, AP2 was found to physically interact with the Gro/Tup1-type corepressor TOPLESS through the EAR motif, and the mutation of the EAR motif in AP2 results in abolished interaction with TOPLESS (Krogan et al, 2012).…”

The EAR Motif Controls the Early Flowering and Senescence Phenotype Mediated by Over-Expression of SlERF36 and Is Partly Responsible for Changes in Stomatal Density and Photosynthesis

“…They show diverse roles such as in herbivory and wounding [14], [15], cold and drought stresses [16], salt stress signalling [17], ABA responses [6] ethylene response [13], [18], [19], JA responses [20] and senescence [21].While the EAR motif has been shown to function as a repressor motif in vitro , its role and the extent of its contribution in governing the processes mediated by its expression are still not clear. We had previously identified SlERF36/SlERF.F.1 (Accession No.…”