Rosa hybrida RhERF1 and RhERF4 mediate ethylene‐ and auxin‐regulated petal abscission by influencing pectin degradation

Abstract

cn). † These authors contributed equally to this work. SUMMARYThe timing of plant organ abscission is modulated by the balance of two hormones, ethylene and auxin, while the mechanism of organ shedding depends on the loss of middle lamella pectin in the abscission zone (AZ). However, the mechanisms involved in sensing the balance of auxin and ethylene and that affect pectin degradation during abscission are not well understood. In this study, we identified two members of the APETALA2/ethylene-responsive factor (AP2/ERF) transcription factor family in rose (Rosa hybrida), RhERF1 and RhERF4 which play a role in petal abscission. The expression of RhERF1 and RhERF4 was influenced by ethylene and auxin, respectively. Reduced expression of RhERF1 or RhERF4 was observed to accelerate petal abscission. Global expression analysis and real-time PCR assays revealed that RhERF1 and RhERF4 modulate the expression of genes encoding pectin-metabolizing enzymes. A reduction in the abundance of pectin epitopes was detected in the AZs of RhERF1 and RhERF4-silenced plants by immunofluorescence microscopy analysis. In addition, RhERF1 and RhERF4 were shown to bind to the promoter of the pectin-metabolizing gene b-GALACTOSIDASE 1 (RhBGLA1), and reduced expression of RhBGLA1 delayed petal abscission. We conclude that during petal abscission, RhERF1 and RhERF4 integrate and coordinate ethylene and auxin signals to modulate pectin metabolism, in part by regulating the expression of RhBGLA1.

Comparative Proteomics Profiling Illuminates the Fruitlet Abscission Mechanism of Sweet Cherry as Induced by Embryo Abortion

“…During the plant organ abscission, a large number of transcription factors are also involved. Including ERF family [49], ARF family [13], MADS-box family [65,66], and HD-ZIP family [16,67]. In the present study, ERF and MADS-box did not accumulate, However, two HD-ZIP family proteins were significantly up-regulated.…”

“…Our proteomics profiling of sweet cherry abscising carpopodium showed bidirectional changes in the expression of the cell wall-related proteins, probably associated not only with the ongoing process of abscission but also with the progressive development of the organs that are not dropped (Table S4). However, it is worth noting that most of the enzymes involved in cell wall degradation showed a trend of up-regulation, including cellulose [3], pectinase [47], polygalacturonase [48], β-galactosidase [49], which play a major role in cell wall degradation. Moreover, the enzymatic activity of cellulose, pectinase and polygalacturonase were significantly higher than non-abscising carpopodium (Figure 2a).…”

Integrative hormone and transcriptome analyses underline the role of abscisic acid in seed shattering of weedy rice

“…Thus, for example, excess ethylene accumulation were observed in tomato and maize mutants characterized by an ABA de cit [41,42]. Contrastingly, ETH and IAA are well-known pivotal effectors of plant organ abscission, and have been shown to act antagonistically to control organ abscission [43]. In this study, pro ling of global gene expressions in AZ revealed DEGs involved in IAA, ETH, and GA pathways ( Table 1, Table S3).…”

A zinc finger protein BBX19 interacts with ABF3 to affect drought tolerance negatively in chrysanthemum

“…The dual-luciferase reporter assay was conducted using the dual-luciferase reporter assay systems (Promega, Madison, WI, USA) and D-luciferin (Promega) as previously described (Gao et al, 2019). The LUC images were taken using an ikon-L936 imaging system (Andor Tech, Belfast, UK).…”