APETALA2/ethylene-responsive factors in higher plant and their roles in regulation of plant stress response.

Plants, anchored throughout their life cycles, face a unique set of challenges from fluctuating environments and pathogenic assaults. Central to their adaptative mechanisms are transcription factors (TFs), particularly the AP2/ERF superfamily-one of the most extensive TF families unique to plants. This family plays instrumental roles in orchestrating diverse biological processes ranging from growth and development to secondary metabolism, and notably, responses to both biotic and abiotic stresses. Distinguished by the presence of the signature AP2 domain or its responsiveness to ethylene signals, the AP2/ERF superfamily has become a nexus of research focus, with increasing literature elucidating its multifaceted roles. This review provides a synoptic overview of the latest research advancements on the AP2/ERF family, spanning its taxonomy, structural nuances, prevalence in higher plants, transcriptional and post-transcriptional dynamics, and the intricate interplay in DNA-binding and target gene regulation. Special attention is accorded to the ethylene response factor B3 subgroup protein Pti5 and its role in stress response, with speculative insights into its functionalities and interaction matrix in tomatoes. The overarching goal is to pave the way for harnessing these TFs in the realms of plant genetic enhancement and novel germplasm development.

Advances of Apetala2/Ethylene Response Factors in Regulating Development and Stress Response in Maize.

Apetala2/ethylene response factor (AP2/ERF) is one of the largest families of transcription factors, regulating growth, development, and stress response in plants. Several studies have been conducted to clarify their roles in Arabidopsis and rice. However, less research has been carried out on maize. In this review, we systematically identified the AP2/ERFs in the maize genome and summarized the research progress related to AP2/ERF genes. The potential roles were predicted from rice homologs based on phylogenetic and collinear analysis. The putative regulatory interactions mediated by maize AP2/ERFs were discovered according to integrated data sources, implying that they involved complex networks in biological activities. This will facilitate the functional assignment of AP2/ERFs and their applications in breeding strategy.

Plant disease resistance outputs regulated by AP2/ERF transcription factor family.

Plants have evolved a complex and elaborate signaling network to respond appropriately to the pathogen invasion by regulating expression of defensive genes through certain transcription factors. The APETALA2/ethylene response factor (AP2/ERF) family members have been determined as key regulators in growth, development, and stress responses in plants. Moreover, a growing body of evidence has demonstrated the critical roles of AP2/ERFs in plant disease resistance. In this review, we describe recent advances for the function of AP2/ERFs in defense responses against microbial pathogens. We summarize that AP2/ERFs are involved in plant disease resistance by acting downstream of mitogen activated protein kinase (MAPK) cascades, and regulating expression of genes associated with hormonal signaling pathways, biosynthesis of secondary metabolites, and formation of physical barriers in an MAPK-dependent or -independent manner. The present review provides a multidimensional perspective on the functions of AP2/ERFs in plant disease resistance, which will facilitate the understanding and future investigation on the roles of AP2/ERFs in plant immunity.

Wide-Range Portrayal of AP2/ERF Transcription Factor Family in Maize (Zea mays L.) Development and Stress Responses.

The APETALA2/Ethylene-Responsive Transcriptional Factors containing conservative AP2/ERF domains constituted a plant-specific transcription factor (TF) superfamily, called AP2/ERF. The configuration of the AP2/ERF superfamily in maize has remained unresolved. In this study, we identified the 229 AP2/ERF genes in the latest (B73 RefGen_v5) maize reference genome. Phylogenetic classification of the ZmAP2/ERF family members categorized it into five clades, including 27 AP2 (APETALA2), 5 RAV (Related to ABI3/VP), 89 DREB (dehydration responsive element binding), 105 ERF (ethylene responsive factors), and a soloist. The duplication events of the paralogous genes occurred from 1.724-25.855 MYA, a key route to maize evolution. Structural analysis reveals that they have more introns and few exons. The results showed that 32 ZmAP2/ERFs regulate biotic stresses, and 24 ZmAP2/ERFs are involved in responses towards abiotic stresses. Additionally, the expression analysis showed that DREB family members are involved in plant sex determination. The real-time quantitative expression profiling of ZmAP2/ERFs in the leaves of the maize inbred line B73 under ABA, JA, salt, drought, heat, and wounding stress revealed their specific expression patterns. Conclusively, this study unveiled the evolutionary pathway of ZmAP2/ERFs and its essential role in stress and developmental processes. The generated information will be useful for stress resilience maize breeding programs.

Genome-wide characterization and expression analysis of AP2/ERF genes in eggplant (Solanum melongena L.).

The AP2/ERF (APETALA2/Ethylene Response Factor) transcription factor superfamily plays crucial roles in a slew of physiological processes, such as plant growth and development, stress response, and secondary metabolites biosynthesis. Eggplant, especially the one rich with anthocyanins, is an economically important horticultural vegetable cultivated worldwide. In this study, we comprehensively analyzed the putative AP2/ERF gene family members and their response to abiotic stress in eggplant. As per the phylogenetic, conserved domains, and motif analysis, 178 AP2/ERF genes in this study belonged to five subfamilies. Chromosomal distributions analysis elucidated stochastic distribution of 178 putative SmAP2/ERF genes across the twelve chromosomes of eggplant. Expression profiles of sixteen selected AP2/ERF genes response to low temperature, drought, salt, abscisic acid, and ethylene treatments were analyzed, which revealed the involvement of SmAP2/ERF genes in diverse signaling pathways. In addition, we integrated RNA-Seq data on anthocyanin biosynthesis in eggplant with yeast one-hybrid and dual-luciferase assays and identified involvement of the SmAP2/ERF genes (Smechr0902114.1 and Smechr1102075.1) in the regulation of anthocyanin biosynthesis. This study will enable further functional characterization of AP2/ERF genes in eggplant and extend the current understanding of the role played by AP2/ERF genes in anthocyanin biosynthesis regulation.

Ethylene responsive factors in the orchestration of stress responses in monocotyledonous plants.

The APETALA2/Ethylene-Responsive Factor (AP2/ERF) superfamily of transcription factors (TFs) regulates physiological, developmental and stress responses. Most of the AP2/ERF TFs belong to the ERF family in both dicotyledonous and monocotyledonous plants. ERFs are implicated in the responses to both biotic and abiotic stress and occasionally impart multiple stress tolerance. Studies have revealed that ERF gene function is conserved in dicots and monocots. Moreover, successful stress tolerance phenotypes are observed on expression in heterologous systems, making ERFs promising candidates for engineering stress tolerance in plants. In this review, we summarize the role of ERFs in general stress tolerance, including responses to biotic and abiotic stress factors, and endeavor to understand the cascade of ERF regulation resulting in successful signal-to-response translation in monocotyledonous plants.