Genes in the ERF family encode transcriptional regulators with a variety of functions involved in the developmental and physiological processes in plants. In this study, a comprehensive computational analysis identified 122 and 139 ERF family genes in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa L. subsp. japonica), respectively. A complete overview of this gene family in Arabidopsis is presented, including the gene structures, phylogeny, chromosome locations, and conserved motifs. In addition, a comparative analysis between these genes in Arabidopsis and rice was performed. As a result of these analyses, the ERF families in Arabidopsis and rice were divided into 12 and 15 groups, respectively, and several of these groups were further divided into subgroups. Based on the observation that 11 of these groups were present in both Arabidopsis and rice, it was concluded that the major functional diversification within the ERF family predated the monocot/dicot divergence. In contrast, some groups/subgroups are species specific. We discuss the relationship between the structure and function of the ERF family proteins based on these results and published information. It was further concluded that the expansion of the ERF family in plants might have been due to chromosomal/segmental duplication and tandem duplication, as well as more ancient transposition and homing. These results will be useful for future functional analyses of the ERF family genes.

/pdf/genome-wide-analysis-of-the-erf-gene-family-in-arabidopsis-33fkj4btth.pdf

Genome-Wide Analysis of the ERF Gene Family in Arabidopsis and Rice

Transcription factors belonging to the APETALA2/Ethylene Responsive Factor (AP2/ERF) family are conservatively widespread in the plant kingdom. These regulatory proteins are involved in the control of primary and secondary metabolism, growth and developmental programs, as well as responses to environmental stimuli. Due to their plasticity and to the specificity of individual members of this family, AP2/ERF transcription factors represent valuable targets for genetic engineering and breeding of crops. In this review, we integrate the evidence collected from functional and structural studies to describe their different mechanisms of action and the regulatory pathways that affect their activity.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.12291

APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factors: mediators of stress responses and developmental programs

The accumulation of storage compounds during seed development ensures the survival of the young seedling, and also provides nutrition to humans and animals in the form of foods and feeds. The putative AP2/EREBP transcription factor WRINKLED1 (WRI1) is involved in the regulation of seed storage metabolism in Arabidopsis. A splicing mutant allele, wri1-1, caused the reduction of seed oil accumulation. Glycolysis was compromised in this mutant, rendering developing embryos unable to efficiently convert sucrose into precursors of triacylglycerol biosynthesis. Expression of the WRINKLED1 cDNA under the control of the cauliflower mosaic virus 35S-promoter led to increased seed oil content. Moreover, the ectopic expression of the WRINKLED1 cDNA caused the accumulation of triacylglycerols in developing seedlings. This effect depended upon the presence of glucose in the growth medium or other sugars readily metabolized to glucose. Oil-accumulating seedlings showed aberrant development consistent with a prolonged embryonic state.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-313X.2004.02235.x

WRINKLED1 encodes an AP2/EREB domain protein involved in the control of storage compound biosynthesis in Arabidopsis

Plants develop unorganized cell masses like callus and tumors in response to various biotic and abiotic stimuli. Since the historical discovery that the combination of two growth-promoting hormones, auxin and cytokinin, induces callus from plant explants in vitro, this experimental system has been used extensively in both basic research and horticultural applications. The molecular basis of callus formation has long been obscure, but we are finally beginning to understand how unscheduled cell proliferation is suppressed during normal plant development and how genetic and environmental cues override these repressions to induce callus formation. In this review, we will first provide a brief overview of callus development in nature and in vitro and then describe our current knowledge of genetic and epigenetic mechanisms underlying callus formation.

/pdf/plant-callus-mechanisms-of-induction-and-repression-swm1rzwn06.pdf

Plant Callus: Mechanisms of Induction and Repression

Selectable marker genes in transgenic plants: applications, alternatives and biosafety

The molecular mechanisms underlying the initiation and maintenance of the embryonic pathway in plants are largely unknown. To obtain more insight into these processes, we used subtractive hybridization to identify genes that are upregulated during the in vitro induction of embryo development from immature pollen grains of Brassica napus (microspore embryogenesis). One of the genes identified, BABY BOOM (BBM), shows similarity to the AP2/ERF family of transcription factors and is expressed preferentially in developing embryos and seeds. Ectopic expression of BBM in Arabidopsis and Brassica led to the spontaneous formation of somatic embryos and cotyledon-like structures on seedlings. Ectopic BBM expression induced additional pleiotropic phenotypes, including neoplastic growth, hormone-free regeneration of explants, and alterations in leaf and flower morphology. The expression pattern of BBM in developing seeds combined with the BBM overexpression phenotype suggests a role for this gene in promoting cell proliferation and morphogenesis during embryogenesis.

Lemin Zhang

Papers

Ectopic expression of BABY BOOM triggers a conversion from vegetative to embryonic growth.