The regulation of chromatin configuration at AGAMOUS locus by LFR-SYD-containing complex is critical for reproductive organ development in Arabidopsis

The SAS chromatin-remodeling complex mediates inflorescence-specific chromatin accessibility for transcription factor binding

While the role of transcription factors in flower development is well understood, the impact of chromatin remodeling on this process remains largely unclear. We conducted a comprehensive analysis to investigate the coordination of the SAS, BAS, and MAS-type SWI/SNF chromatin-remodeling complexes with transcription factors to regulate chromatin accessibility and gene transcription during flower development in Arabidopsis thaliana. Our findings indicate that the SAS complex binds to numerous genes related to flower development and is responsible for establishing chromatin accessibility of these genes in inflorescences. In contrast, the BAS and MAS complexes exhibit minimal involvement in regulating the accessibility of these genes. The SAS-bound genomic regions and the SAS-dependent accessible regions in infloresences are enriched with sites occupied by multiple MADS family transcription factors involved in flower development. Furthermore, we found that the SAS-dependent accessibility facilitates the binding of the MADS transcription factor AP1 to a subset of its target loci. This study highlights the dynamic role of the SAS complex in modulating the chromatin accessibility and genomic binding of transcription factors during plant development.

The Transcription Factor WFZP Interacts with the Chromatin Remodeler TaSYD to Regulate Root Architecture and Nitrogen Uptake Efficiency in Wheat

The root architecture is crucial for the robust growth and nutrient absorption in cereals. However, it is urgent to identify the factors that simultaneously optimize root architecture and nutrient utilization in wheat. In this study, a beneficial role of the class II AP2/ERF transcription factor WHEAT FRIZZY PANICLE (WFZP) on lateral root number (LRN), root length (RL), and nitrogen utilization is revealed. In addition, interactors of WFZP including TaSYD are identified, as a subunit of the chromatin remodeling complex. The Tasyd mutants show a significant reduction in LRN, RL, and nitrogen uptake efficiency, resembling the phenotype of wfzp mutants. Furthermore, it is revealed that the WFZP-TaSYD module promotes the expression of root development and nitrate uptake-related genes by modulating chromatin accessibility and histone modifications. Finally, an elite allele (WFZP-A-I) associated with improved LRN and thousand-grain weight (TGW) is identified. Hence, these findings not only unveil the mechanisms underlying the coordination of root development and nitrogen uptake efficiency, but also provide valuable targets for breeding high-yield crops.

Composition and function of plant chromatin remodeling complexes

ATP-dependent chromatin remodelers play a crucial role in modifying chromatin configuration by utilizing the energy of ATP hydrolysis. They are involved in various processes, including transcription, DNA replication, and maintaining genome stability. These remodeling remodelers usually form multi-subunit chromatin remodeling complexes in eukaryotes. In plants, chromatin remodeling complexes have diverse functions in regulating plant development and stress response. Recent studies have conducted extensive research on plant chromatin remodeling complexes. This review focuses on recent advances in the classification and composition of plant chromatin remodeling complexes, the protein-protein interactions within the complexes, their impact on chromatin configuration, and their interactions with chromatin modifications and transcription factors.

Reflections on the ABC model of flower development

The formulation of the ABC model by a handful of pioneer plant developmental geneticists was a seminal event in the quest to answer a seemingly simple question: how are flowers formed? Fast forward 30 years and this elegant model has generated a vibrant and diverse community, capturing the imagination of developmental and evolutionary biologists, structuralists, biochemists and molecular biologists alike. Together they have managed to solve many floral mysteries, uncovering the regulatory processes that generate the characteristic spatio-temporal expression patterns of floral homeotic genes, elucidating some of the mechanisms allowing ABC genes to specify distinct organ identities, revealing how evolution tinkers with the ABC to generate morphological diversity, and even shining a light on the origins of the floral gene regulatory network itself. Here we retrace the history of the ABC model, from its genesis to its current form, highlighting specific milestones along the way before drawing attention to some of the unsolved riddles still hidden in the floral alphabet.

Old school, new rules: floral meristem development revealed by 3D gene expression atlases and high-resolution transcription factor-chromatin dynamics

The intricate morphology of the flower is primarily established within floral meristems in which floral organs will be defined and from where the developing flower will emerge. Floral meristem development involves multiscale-level regulation, including lineage and positional mechanisms for establishing cell-type identity, and transcriptional regulation mediated by changes in the chromatin environment. However, many key aspects of floral meristem development remain to be determined, such as: 1) the exact role of cellular location in connecting transcriptional inputs to morphological outcomes, and 2) the precise interactions between transcription factors and chromatin regulators underlying the transcriptional networks that regulate the transition from cell proliferation to differentiation during floral meristem development. Here, we highlight recent studies addressing these points through newly developed spatial reconstruction techniques and high-resolution transcription factor-chromatin environment interactions in the model plant Arabidopsis thaliana. Specifically, we feature studies that reconstructed 3D gene expression atlases of the floral meristem. We also discuss how the precise timing of floral meristem specification, floral organ patterning, and floral meristem termination is determined through temporally defined epigenetic dynamics for fine-tuning of gene expression. These studies offer fresh insights into the well-established principles of floral meristem development and outline the potential for further advances in this field in an age of integrated, powerful, multiscale resolution approaches.