Transcription Factor VlbZIP14 Inhibits Postharvest Grape Berry Abscission by Directly Activating VlCOMT and Promoting Lignin Biosynthesis.

Sulfur dioxide (SO2) is the most effective preservative for table grapes as it reduces the respiratory intensity of berries and inhibits mold growth. However, excessive SO2 causes berry abscission during storage, resulting in an economic loss postharvest. In this study, grapes were exogenously treated with SO2, SO2 + 1.5% chitosan, SO2 + 1.5% eugenol, and SO2 + eugenol-loaded chitosan nanoparticles (SN). In comparison to SO2 treatment, SN treatment reduced the berries' abscission rate by 74% while maintaining the quality of the berries. Among the treatments, SN treatment most effectively inhibited berry abscission and maintained berry quality. RNA-sequencing (RNA-seq) revealed that SN treatment promoted the expression of genes related to cell wall metabolism. Among these genes, VlCOMT was detected as the central gene, playing a key role in mediating the effects of SN. Dual luciferase and yeast one-hybrid (Y1H) assays demonstrated that VlbZIP14 directly activated VlCOMT by binding to the G-box motif in the latter's promoter, which then participated in lignin synthesis. Our results provide key insights into the molecular mechanisms underlying the SN-mediated inhibition of berry abscission and could be used to improve the commercial value of SO2-treated postharvest table grapes.

Molecular and mechanical mechanisms of animal cell abscission.

Cytokinesis leads to the distribution of segregated chromosomes, membrane, and cytoplasmic material in the two daughter cells, and ultimately concludes with abscission, their physical separation. In this Graphical Review, we outline the key events that lead to abscission and discuss mechanisms of delayed abscisison.

Dormancy regulator Prunus mume DAM6 promotes ethylene-mediated leaf senescence and abscission.

Leaf senescence and abscission in autumn are critical phenological events in deciduous woody perennials. After leaf fall, dormant buds remain on deciduous woody perennials, which then enter a winter dormancy phase. Thus, leaf fall is widely believed to be linked to the onset of dormancy. In Rosaceae fruit trees, DORMANCY-ASSOCIATED MADS-box (DAM) transcription factors control bud dormancy. However, apart from their regulatory effects on bud dormancy, the biological functions of DAMs have not been thoroughly characterized. In this study, we revealed a novel DAM function influencing leaf senescence and abscission in autumn. In Prunus mume, PmDAM6 expression was gradually up-regulated in leaves during autumn toward leaf fall. Our comparative transcriptome analysis using two RNA-seq datasets for the leaves of transgenic plants overexpressing PmDAM6 and peach (Prunus persica) DAM6 (PpeDAM6) indicated Prunus DAM6 may up-regulate the expression of genes involved in ethylene biosynthesis and signaling as well as leaf abscission. Significant increases in 1-aminocyclopropane-1-carboxylate accumulation and ethylene emission in DEX-treated 35S:PmDAM6-GR leaves reflect the inductive effect of PmDAM6 on ethylene biosynthesis. Additionally, ethephon treatments promoted autumn leaf senescence and abscission in apple and P. mume, mirroring the changes due to PmDAM6 overexpression. Collectively, these findings suggest that PmDAM6 may induce ethylene emission from leaves, thereby promoting leaf senescence and abscission. This study clarified the effects of Prunus DAM6 on autumn leaf fall, which is associated with bud dormancy onset. Accordingly, in Rosaceae, DAMs may play multiple important roles affecting whole plant growth during the tree dormancy induction phase.

LcMPK3 and LcMPK6 positively regulate fruitlet abscission in litchi.

Mitogen-activated protein kinase (MAPK) cascades have been discovered to play a fundamental role in regulating organ abscission. However, the identity of protein substrates targeted by MAPK cascades, as well as whether the role of MAPK protein cascades in the abscission process is conserved across different plant species, remain unknown. Here, the role of homologs of MPK3 and MPK6 in regulating fruit abscission were characterized in litchi. Ectopic expression of LcMPK3 or LcMPK6 in Arabidopsis mpk3 mpk6 mutant rescued the deficiency in floral organ abscission, while silencing of LcMPK3 or LcMPK6 in litchi significantly decreased fruitlet abscission. Importantly, a total of 49 proteins interacting with LcMPK3 were identified through yeast two-hybrid screening, including two components of the MAPK signaling cascade, five transcription factors, and two aquaporins. Furthermore, the interaction between LcMPK3/6 with LcBZR1/2, core components in brassinosteroids signaling that suppress litchi fruitlet abscission, was confirmed using in vitro and in vivo assays. Moreover, phos-tag assays demonstrated that LcMPK3/6 could phosphorylate LcBZR1/2, with several phosphorylation residues identified. Together, our findings suggest that LcMPK3 and LcMPK6 play a positive regulatory role in fruitlet abscission in litchi, and offer crucial information for the investigation of mechanisms underlying MPK3/6-mediated organ abscission in plants.

Transcriptomic landscape of seedstick in Arabidopsis thaliana funiculus after fertilisation.

BACKGROUND: In Angiosperms, the continuation of plant species is intricately dependent on the funiculus multifaceted role in nutrient transport, mechanical support, and dehiscence of seeds. SEEDSTICK (STK) is a MADS-box transcription factor involved in seed size and abscission, and one of the few genes identified as affecting funiculus growth. Given the importance of the funiculus to a correct seed development, allied with previous phenotypic observations of stk mutants, we performed a transcriptomic analysis of stk funiculi from floral stage 17, using RNA-sequencing, to infer on the deregulated networks of genes. RESULTS: The generated dataset of differentially expressed genes was enriched with cell wall biogenesis, cell cycle, sugar metabolism and transport terms, all in accordance with stk phenotype observed in funiculi from floral stage 17. We selected eight differentially expressed genes for transcriptome validation using qPCR and/or promoter reporter lines. Those genes were involved with abscission, seed development or novel functions in stk funiculus, such as hormones/secondary metabolites transport. CONCLUSION: Overall, the analysis performed in this study allowed delving into the STK-network established in Arabidopsis funiculus, fulfilling a literature gap. Simultaneously, our findings reinforced the reliability of the transcriptome, making it a valuable resource for candidate genes selection for functional genetic studies in the funiculus. This will enhance our understanding on the regulatory network controlled by STK, on the role of the funiculus and how seed development may be affected by them.

Transcriptome analysis unravels key pathways and hub genes related to immature fruit abscission in Camellia oleifera.

Immature fruit abscission of Camellia oleifera (C. oleifera) is a common problem limiting yield increases. However, the regulatory mechanisms underlying immature fruit abscission in C. oleifera are unclear. In this study, we systematically investigated changes in the morphological, physiological, and gene expression of fruit abscission zones (FAZs) of soon-to-abscise fruits (M2). We found that fruit abscission before ripening mainly occurs during the August abscission stage of 'Huashuo'. At the beginning of this stage, the FAZs of M2 have a marked dent, and the separation layer structures are preliminarily formed. Phytohormone analysis showed that the contents of indole-3-acetic acid (IAA) and jasmonic acid (JA) in the FAZs of M2 were significantly decreased compared with the non-abscised fruits, while the content of trans-zeatin (TZR) was increased. Transcriptome analysis identified differentially expressed genes (DEGs) mainly involved in phytohormone metabolism, including ethylene, auxin, JA, and the cis-zeatin signal transduction pathway. There were also many DEGs involved in cell wall catabolism. Weighted gene co-expression network analysis (WGCNA) further suggested that the transcription factors NAC100 and ERF114 participate in the immature fruit abscission of C. oleifera. This study provides insights into the fruit abscission mechanism of C. oleifera.

Cytokinetic abscission in Toxoplasma gondii is governed by protein phosphatase 2A and the daughter cell scaffold complex.

Cytokinetic abscission marks the final stage of cell division, during which the daughter cells physically separate through the generation of new barriers, such as the plasma membrane or cell wall. While the contractile ring plays a central role during cytokinesis in bacteria, fungi and animal cells, the process diverges in Apicomplexa. In Toxoplasma gondii, two daughter cells are formed within the mother cell by endodyogeny. The mechanism by which the progeny cells acquire their plasma membrane during the disassembly of the mother cell, allowing daughter cells to emerge, remains unknown. Here we identify and characterize five T. gondii proteins, including three protein phosphatase 2A subunits, which exhibit a distinct and dynamic localization pattern during parasite division. Individual downregulation of these proteins prevents the accumulation of plasma membrane at the division plane, preventing the completion of cellular abscission. Remarkably, the absence of cytokinetic abscission does not hinder the completion of subsequent division cycles. The resulting progeny are able to egress from the infected cells but fail to glide and invade, except in cases of conjoined twin parasites.

Reactive Oxygen and Related Regulatory Factors Involved in Ethylene-Induced Petal Abscission in Roses.

Petal abscission affects the growth, development, and economic value of plants, but the mechanism of ethylene-ROS-induced petal abscission is not clear. Therefore, we treated roses with different treatments (MOCK, ETH, STS, and ETH + STS), and phenotypic characteristics of petal abscission, changed ratio of fresh weight, morphology of cells in AZ and the expression of RhSUC2 were analyzed. On this basis, we measured reactive oxygen species (ROS) content in petals and AZ cells of roses, and analyzed the expression levels of some genes related to ROS production and ROS scavenging. Ethylene promoted the petal abscission of rose through decreasing the fresh weight of the flower, promoting the stacking and stratification of AZ cells, and repressing the expression of RhSUC2. During this process, ethylene induced the ROS accumulation of AZ cells and petals mainly through increasing the expressions of some genes (RhRHS17, RhIDH1, RhIDH-III, RhERS, RhPBL32, RhFRS5, RhRAC5, RhRBOHD, RhRBOHC, and RhPLATZ9) related to ROS production and repressing those genes (RhCCR4, RhUBC30, RhSOD1, RhAPX6.1, and RhCATA) related to ROS scavenging. In summary, ROS and related regulatory factors involved in ethylene induced petal abscission in roses.

The single RRM domain-containing protein SARP1 is required for establishment of the separation zone in Arabidopsis.

Abscission is the shedding of plant organs in response to developmental and environmental cues. Abscission involves cell separation between two neighboring cell types, residuum cells (RECs) and secession cells (SECs) in the floral abscission zone (AZ) in Arabidopsis thaliana. However, the regulatory mechanisms behind the spatial determination that governs cell separation are largely unknown. The class I KNOTTED-like homeobox (KNOX) transcription factor BREVIPEDICELLUS (BP) negatively regulates AZ cell size and number in Arabidopsis. To identify new players participating in abscission, we performed a genetic screen by activation tagging a weak complementation line of bp-3. We identified the mutant ebp1 (enhancer of BP1) displaying delayed floral organ abscission. The ebp1 mutant showed a concaved surface in SECs and abnormally stacked cells on the top of RECs, in contrast to the precisely separated surface in the wild-type. Molecular and histological analyses revealed that the transcriptional programming during cell differentiation in the AZ is compromised in ebp1. The SECs of ebp1 have acquired REC-like properties, including cuticle formation and superoxide production. We show that SEPARATION AFFECTING RNA-BINDING PROTEIN1 (SARP1) is upregulated in ebp1 and plays a role in the establishment of the cell separation layer during floral organ abscission in Arabidopsis.

Effect of simulated extreme rainfall on the vegetative phenology of perennial and annual herbaceous plants from a Brazilian dry forest.

Detecting changes in the phenological responses of herbaceous species as a function of predicted climate change is important for forecasting future scenarios for the functioning of dry tropical forests, especially when predicting an increase in the frequency and intensity of extreme droughts. Because of the sensitivity of plants to water availability, our study hypothesizes that if years become drier or wetter, herbaceous plants will synchronously change the onset, duration, and intensity of their vegetative phenophases. We used a historical series of 60 years of precipitation observations for the Caatinga vegetation to define daily average of precipitation for rainy (Twet), median (Tcontrol), and dry (Tdry) years. We simulated past average daily rainfall (Twet, Tcontrol, and Tdry) while growing two herbaceous perennials and two herbaceous annuals. We monitored plant growth and measured the activity (absence or presence) and intensity of vegetative phenophases. We used circular statistical analysis to assess differences between treatments. Our results revealed that leaf production was seasonal but relatively uniform for perennial species and highly seasonal (wet season) for annual species. Simulated dry years induced lower leaf emergence concentrated over a few months in annual species, but this effect was more strongly significant in one of the two perennial species. Both annual and perennial species can experience delayed and less intense leaf abscission during the rainy season in years with below-average precipitation. In contrast, large voluminous rains in years with above-average precipitation can accelerate and intensify the process of leaf renewal. If future precipitation reductions occur, the changes in phenological response indicate that the cover of annual and perennial herbaceous species in this study will likely decrease, altering the landscape and functioning of dry tropical forests. However, the potential trade-offs observed may help populations of these species to persist during years of severe drought in the Caatinga.

Comparative histology of abscission zones reveals the extent of convergence and divergence in seed shattering in weedy and cultivated rice.

The modification of seed shattering has been a recurring theme in rice evolution. The wild ancestor of cultivated rice disperses its seeds, but reduced shattering was selected during multiple domestication events to facilitate harvesting. Conversely, selection for increased shattering occurred during the evolution of weedy rice, a weed invading cultivated rice fields that has originated multiple times from domesticated ancestors. Shattering requires formation of a tissue known as the abscission zone (AZ), but how the AZ has been modified throughout rice evolution is unclear. We quantitatively characterized the AZ characteristics of relative length, discontinuity, and intensity in 86 cultivated and weedy rice accessions. We reconstructed AZ evolutionary trajectories and determined the degree of convergence among different cultivated varieties and among independent weedy rice populations. AZ relative length emerged as the best feature to distinguish high and low shattering rice. Cultivated varieties differed in average AZ morphology, revealing lack of convergence in how shattering reduction was achieved during domestication. In contrast, weedy rice populations typically converged on complete AZs, irrespective of origin. By examining AZ population-level morphology, our study reveals its evolutionary plasticity, and suggests that the genetic potential to modify the ecologically and agronomically important trait of shattering is plentiful in rice lineages.

Multifaceted mechanisms controlling grain disarticulation in the Poaceae.

Cereal shattering and threshability, both involving disarticulation of grains from the mother plant, are important traits for cereal domestication and improvement. Recent studies highlighted diverse mechanisms influencing shattering and threshability, either through development of the disarticulation zone or floral structures enclosing or supporting the disarticulation unit. Differential lignification in the disarticulation zone is essential for rice shattering but not required for many other grasses. During shattering, the disarticulation zone undergoes either abscission leading to cell separation or cell breakage. Threshability can be affected by the morphology and toughness of the enclosing floral structures, and in some species, by the inherent weakness of the disarticulation zone. Fine-tuning shattering and threshability is essential for breeding wild and less domesticated cereals.

A multifaceted kinase axis regulates plant organ abscission through conserved signaling mechanisms.

Plants have evolved mechanisms to abscise organs as they develop or when exposed to unfavorable conditions.1 Uncontrolled abscission of petals, fruits, or leaves can impair agricultural productivity.2,3,4,5 Despite its importance for abscission progression, our understanding of the IDA signaling pathway and its regulation remains incomplete. IDA is secreted to the apoplast, where it is perceived by the receptors HAESA (HAE) and HAESA-LIKE2 (HSL2) and somatic embryogenesis receptor kinase (SERK) co-receptors.6,7,8,9 These plasma membrane receptors activate an intracellular cascade of mitogen-activated protein kinases (MAPKs) by an unknown mechanism.10,11,12 Here, we characterize brassinosteroid signaling kinases (BSKs) as regulators of floral organ abscission in Arabidopsis. BSK1 localizes to the plasma membrane of abscission zone cells, where it interacts with HAESA receptors to regulate abscission. Furthermore, we demonstrate that YODA (YDA) has a leading role among other MAPKKKs in controlling abscission downstream of the HAESA/BSK complex. This kinase axis, comprising a leucine-rich repeat receptor kinase, a BSK, and an MAPKKK, is known to regulate stomatal patterning, early embryo development, and immunity.10,13,14,15,16 How specific cellular responses are obtained despite signaling through common effectors is not well understood. We show that the identified abscission-promoting allele of BSK1 also enhances receptor signaling in other BSK-mediated pathways, suggesting conservation of signaling mechanisms. Furthermore, we provide genetic evidence supporting independence of BSK1 function from its kinase activity in several developmental processes. Together, our findings suggest that BSK1 facilitates signaling between plasma membrane receptor kinases and MAPKKKs via conserved mechanisms across multiple facets of plant development.

Species-Specific miRNAs Contribute to the Divergence between Deciduous and Evergreen Species in Ilex.

MicroRNAs (miRNAs) are pivotal regulators of gene expression, playing crucial roles in plant developmental processes and environmental responses. However, the function of miRNAs in influencing deciduous traits has been little explored. Here, we utilized sRNA-seq on two deciduous species, Ilex polyneura (Hand.-Mazz.) S. Y. Hu and Ilex asprella Champ. ex Benth., along with an evergreen species, Ilex latifolia Thunb., to identify and annotate miRNAs within these species. Our analysis revealed 162 species-specific miRNAs (termed SS-miRNAs) from 120 families, underscoring the fundamental roles and potential influence of SS-miRNAs on plant phenotypic diversity and adaptation. Notably, three SS-miRNAs in I. latifolia were found to target crucial genes within the abscission signaling pathway. Analysis of cis-regulatory elements suggested a novel regulatory relationship that may contribute to the evergreen phenotype of I. latifolia by modulating the abscission process in a light-independent manner. These findings propose a potential mechanism by which SS-miRNAs can influence the conserved abscission pathway, contributing to the phenotypic divergence between deciduous and evergreen species within the genus Ilex.

MassARRAY and SABER Analyses of SNPs in Embryo DNA Reveal the Abscission of Self-Fertilised Progeny during Fruit Development of Macadamia (Macadamia integrifolia Maiden & Betche).

Yield in many crops is affected by abscission during the early stages of fruitlet development. The reasons for fruitlet abscission are often unclear but they may include genetic factors because, in some crops, self-pollinated fruitlets are more likely to abscise than cross-pollinated fruitlets. Pollen parentage can also affect final fruit size and fruit quality. Here, we aimed to understand the effects of pollen parentage on fruitlet retention and nut quality in orchards of macadamia (Macadamia integrifolia Maiden & Betche). We identified the pollen parent of macadamia 'cultivar '816' embryos by analysing single nucleotide polymorphisms (SNPs) in their DNA using customised MassARRAY and Single Allele Base Extension Reaction (SABER) methods. This allowed us to determine the proportions of self-fertilised and cross-fertilised progeny during premature fruit drop at 6 weeks and 10 weeks after peak anthesis, as well as at nut maturity. We determined how pollen parentage affected nut-in-shell (NIS) mass, kernel mass, kernel recovery, and oil concentration. Macadamia trees retained cross-fertilised fruitlets rather than self-fertilised fruitlets. The percentage of progeny that were cross-fertilised increased from 6% at 6 weeks after peak anthesis to 97% at nut maturity, with each tree producing on average 22 self-fertilised nuts and 881 cross-fertilised nuts. Three of the four cross-pollen parents provided fruit with significantly higher NIS mass, kernel mass, or kernel recovery than the few remaining self-fertilised fruit. Fruit that were cross-fertilised by '842', 'A4', or 'A203' had 16-29% higher NIS mass and 24-44% higher kernel mass than self-fertilised fruit. Nuts that were cross-fertilised by 'A4' or 'A203' also had 5% or 6% higher kernel recovery, worth approximately $US460-540 more per ton for growers than self-fertilised nuts. The highly selective abscission of self-fertilised fruitlets and the lower nut quality of self-fertilised fruit highlight the critical importance of cross-pollination for macadamia productivity.

Corrigendum: The LcKNAT1-LcEIL2/3 regulatory module is involved in fruitlet abscission in litchi.

[This corrects the article DOI: 10.3389/fpls.2021.802016.].

Identification of PavHB16 gene in Prunus avium and validation of its function in Arabidopsis thaliana.

Sweet cherry (Prunus avium L.) is one of the most economically important fruits in the world. However, severe fruit abscission has brought significant challenges to the cherry industry. To better understand the molecular regulation mechanisms underlying excessive fruit abscission in sweet cherry, the fruit abscission characteristics, the anatomical characteristics of the abscission zone (AZ), as well as a homeodomain-Leucine Zipper gene family member PavHB16 function were analyzed. The results showed that the sweet cherry exhibited two fruit abscission peak stages, with the "Brooks" cultivar demonstrating the highest fruit-dropping rate (97.14%). During these two fruit abscission peak stages, both the retention pedicel and the abscising pedicel formed AZs. but the AZ in the abscising pedicel was more pronounced. In addition, a transcription factor, PavHB16, was identified from sweet cherry. The evolutionary analysis showed that there was high homology between PavHB16 and AtHB12 in Arabidopsis. Moreover, the PavHB16 protein was localized in the nucleus. Overexpression of PavHB16 in Arabidopsis accelerated petal shedding. In the PavHB16-overexpressed lines, the AZ cells in the pedicel became smaller and denser, and the expression of genes involved in cell wall remodeling, such as cellulase 3 gene (AtCEL3), polygalacturonase 1 (AtPG1), and expandin 24(AtEXPA24) were upregulated. The results suggest that PavHB16 may promote the expression of genes related to cell wall remodeling, ultimately facilitating fruit abscission. In summary, this study cloned the sweet cherry PavHB16 gene and confirmed its function in regulating sweet cherry fruit abscission, which provided new data for further study on the fruit abscission mechanism. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01443-8.

Auxin efflux carrier PsPIN4 identified through genome-wide analysis as vital factor of petal abscission.

PIN-FORMED (PIN) proteins, which function as efflux transporters, play many crucial roles in the polar transportation of auxin within plants. In this study, the exogenous applications of auxin IAA and TIBA were found to significantly prolong and shorten the florescence of tree peony (Paeonia suffruticosa Andr.) flowers. This finding suggests that auxin has some regulatory influence in petal senescence and abscission. Further analysis revealed a total of 8 PsPINs distributed across three chromosomes, which could be categorized into two classes based on phylogenetic and structural analysis. PsPIN1, PsPIN2a-b, and PsPIN4 were separated into the "long" PIN category, while PsPIN5, PsPIN6a-b, and PsPIN8 belonged to the "short" one. Additionally, the cis-regulatory elements of PsPIN promoters were associated with plant development, phytohormones, and environmental stress. These genes displayed tissue-specific expression, and phosphorylation sites were abundant throughout the protein family. Notably, PsPIN4 displayed distinct and elevated expression levels in roots, leaves, and flower organs. Expression patterns among the abscission zone (AZ) and adjacent areas during various flowering stages and IAA treatment indicate that PsPIN4 likely influences the initiation of peony petal abscission. The PsPIN4 protein was observed to be co-localized on both the plasma membrane and the cell nucleus. The ectopic expression of PsPIN4 reversed the premature flower organs abscission in the Atpin4 and significantly protracted florescence when introduced to Col Arabidopsis. Our findings established a strong basis for further investigation of PIN gene biological functions, particularly concerning intrinsic relationship between PIN-mediated auxin polar.

JOINTLESS Maintains Inflorescence Meristem Identity in Tomato.

JOINTLESS (J) was isolated in tomato (Solanum lycopersicum) from mutants lacking a flower pedicel abscission zone (AZ) and encodes a MADS-box protein of the SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 subfamily. The loss of J function also causes the return to leaf initiation in the inflorescences, indicating a pivotal role in inflorescence meristem identity. Here, we compared jointless (j) mutants in different accessions that exhibit either an indeterminate shoot growth, producing regular sympodial segments, or a determinate shoot growth, due to the reduction of sympodial segments and causal mutation of the SELF-PRUNING (SP) gene. We observed that the inflorescence phenotype of j mutants is stronger in indeterminate (SP) accessions such as Ailsa Craig (AC), than in determinate (sp) ones, such as Heinz (Hz). Moreover, RNA-seq analysis revealed that the return to vegetative fate in j mutants is accompanied by expression of SP, which supports conversion of the inflorescence meristem to sympodial shoot meristem in j inflorescences. Other markers of vegetative meristems such as APETALA2c and branching genes such as BRANCHED 1 (BRC1a/b) were differentially expressed in the inflorescences of j(AC) mutant. We also found in the indeterminate AC accession that J represses homeotic genes of B- and C-classes and that its overexpression causes an oversized leafy calyx phenotype and has a dominant negative effect on AZ formation. A model is therefore proposed where J, by repressing shoot fate and influencing reproductive organ formation, acts as a key determinant of inflorescence meristems.

An ethylene response factor AcERF116 identified from A. catechu is involved in fruitlet abscission.

Procedural abscission of outer reproductive organs during flower and fruit development occurs in most plant lineages. Undesired abscission, such as fruitlet shedding causes considerable yield loss in many fruit-producing species. Ethylene is one of the key factors regulating organ abscission. However, the participants involved in the ethylene-mediated abscission pathway remains largely unidentified. In this study, we focused on the ethylene response transcription factors (ERFs) regulating fruitlet abscission in an industrial tree species, A. catechu. A total of 165 ERF genes have been found in the A. catechu genome and eight of these showed distinct expression between the "about-to-abscise" and "non-abscised" samples. An AcERF116 gene with high expression level in the fruit abscission zone (FAZ) was selected for further study. Overexpression of the AcERF116 gene accelerated cell separation in the abscission zone (AZ) and promoted pedicel abscission in transgenic tomato lines. The PG (ploygalacturonase) activity was enhanced in the FAZs of A. catechu fruitlets during ethylene-induced fruitlet abscission, while the PME (pectin methylesterase) activity was suppressed. In addition, cytosolic alkalization was observed in the AZs during abscission in both tomato and A. catechu. Our results suggest that AcERF116 plays a critical role in the crosstalk of ethylene and fruitlet abscission in A. catechu.