Developmental constraint underlies the replicated evolution of grass awns.

Replicated trait evolution can provide insights into the mechanisms underlying the evolution of biodiversity. One example of replicated evolution is the awn, an organ elaboration in grass inflorescences. Awns are likely homologous to leaf blades.

() and () homologs share conserved roles in growth repression.

Crop engineering and de novo domestication using gene editing are new frontiers in agriculture. However, outside of well-studied crops and model systems, prioritizing engineering targets remains challenging. Evolution can guide us, revealing genes with deeply conserved roles that have repeatedly been selected in the evolution of plant form.

Asymmetric Evolution of Protein Domains in the Leucine-Rich Repeat Receptor-Like Kinase Family of Plant Signaling Proteins.

The coding sequences of developmental genes are expected to be deeply conserved, with cis-regulatory change driving the modulation of gene function. In contrast, proteins with roles in defense are expected to evolve rapidly, in molecular arms races with pathogens. However, some gene families include both developmental and defense genes.

The Power and Perils of De Novo Domestication Using Genome Editing.

There is intense interest in using genome editing technologies to domesticate wild plants, or accelerate the improvement of weakly domesticated crops, in de novo domestication. Here, we discuss promising genetic strategies, with a focus on plant development. Importantly, genome editing releases us from dependence on random mutagenesis or intraspecific diversity, allowing us to draw solutions more broadly from diversity.

Conserved pleiotropy of an ancient plant homeobox gene uncovered by cis-regulatory dissection.

Divergence of gene function is a hallmark of evolution, but assessing functional divergence over deep time is not trivial. The few alleles available for cross-species studies often fail to expose the entire functional spectrum of genes, potentially obscuring deeply conserved pleiotropic roles. Here, we explore the functional divergence of WUSCHEL HOMEOBOX9 (WOX9), suggested to have species-specific roles in embryo and inflorescence development.

Evolution of buffering in a genetic circuit controlling plant stem cell proliferation.

Precise control of plant stem cell proliferation is necessary for the continuous and reproducible development of plant organs. The peptide ligand CLAVATA3 (CLV3) and its receptor protein kinase CLAVATA1 (CLV1) maintain stem cell homeostasis within a deeply conserved negative feedback circuit. In Arabidopsis, CLV1 paralogs also contribute to homeostasis, by compensating for the loss of CLV1 through transcriptional upregulation.

The CLAVATA receptor FASCIATED EAR2 responds to distinct CLE peptides by signaling through two downstream effectors.

Meristems contain groups of indeterminate stem cells, which are maintained by a feedback loop between () and () signaling. CLV signaling involves the secretion of the CLV3 peptide and its perception by a number of Leucine-Rich-Repeat (LRR) receptors, including the receptor-like kinase CLV1 and the receptor-like protein CLV2 coupled with the CORYNE (CRN) pseudokinase. CLV2, and its maize ortholog FASCIATED EAR2 (FEA2) appear to function in signaling by CLV3 and several related CLV3/EMBRYO-SURROUNDING REGION (CLE) peptide ligands.

An ancient Sec10-formin fusion provides insights into actin-mediated regulation of exocytosis.

Exocytosis, facilitated by the exocyst, is fundamentally important for remodeling cell walls and membranes. Here, we analyzed , a novel gene that encodes a fusion of an exocyst subunit (Sec10) and an actin nucleation factor (formin). We showed that the fusion occurred early in moss evolution and has been retained for more than 170 million years.

Changing MADS-Box Transcription Factor Protein-Protein Interactions as a Mechanism for Generating Floral Morphological Diversity.

Flowers display fantastic morphological diversity. Despite extreme variability in form, floral organ identity is specified by a core set of deeply conserved proteins-the floral MADS-box transcription factors. This indicates that while core gene function has been maintained, MADS-box transcription factors have evolved to regulate different downstream genes.

Engineering Quantitative Trait Variation for Crop Improvement by Genome Editing.

Major advances in crop yields are needed in the coming decades. However, plant breeding is currently limited by incremental improvements in quantitative traits that often rely on laborious selection of rare naturally occurring mutations in gene-regulatory regions. Here, we demonstrate that CRISPR/Cas9 genome editing of promoters generates diverse cis-regulatory alleles that provide beneficial quantitative variation for breeding.

A Gene for Genetic Background in Zea mays: Fine-Mapping enhancer of teosinte branched1.2 to a YABBY Class Transcription Factor.

The effects of an allelic substitution at a gene often depend critically on genetic background, i.e., the genotypes at other genes in the genome.

The Maize PI/GLO Ortholog Zmm16/sterile tassel silky ear1 Interacts with the Zygomorphy and Sex Determination Pathways in Flower Development.

In monocots and eudicots, B class function specifies second and third whorl floral organ identity as described in the classic ABCE model. Grass B class APETALA3/DEFICIENS orthologs have been functionally characterized; here, we describe the positional cloning and characterization of a maize (Zea mays) PISTILLATA/GLOBOSA ortholog Zea mays mads16 (Zmm16)/sterile tassel silky ear1 (sts1). We show that, similar to many eudicots, all the maize B class proteins bind DNA as obligate heterodimers and positively regulate their own expression.

Meristem identity and phyllotaxis in inflorescence development.

Inflorescence morphology is incredibly diverse. This diversity of form has been a fruitful source of inquiry for plant morphologists for more than a century. Work in the grasses (Poaceae), the tomato family (Solanaceae), and Arabidopsis thaliana (Brassicaceae) has led to a richer understanding of the molecular genetics underlying this diversity.

Protein change in plant evolution: tracing one thread connecting molecular and phenotypic diversity.

Proteins change over the course of evolutionary time. New protein-coding genes and gene families emerge and diversify, ultimately affecting an organism's phenotype and interactions with its environment. Here we survey the range of structural protein change observed in plants and review the role these changes have had in the evolution of plant form and function.

Changes in expression pattern of the teosinte branched1-like genes in the Zingiberales provide a mechanism for evolutionary shifts in symmetry across the order.

Premise Of The Study: Floral symmetry is a trait of key importance when considering floral diversification because it is thought to play a significant role in plant-pollinator interactions. The CYCLOIDEA/TEOSINTE BRANCHED1 (CYC/TB1)-like genes have been implicated in the development and evolution of floral symmetry in numerous lineages. We thus chose to investigate a possible role for these genes in the evolution of floral symmetry within petaloid monocots, using the order Zingiberales as a model system.

Evidence for the involvement of Globosa-like gene duplications and expression divergence in the evolution of floral morphology in the Zingiberales.

*The MADS box transcription factor family has long been identified as an important contributor to the control of floral development. It is often hypothesized that the evolution of floral development across angiosperms and within specific lineages may occur as a result of duplication, functional diversification, and changes in regulation of MADS box genes. Here we examine the role of Globosa (GLO)-like genes, members of the B-class MADS box gene lineage, in the evolution of floral development within the monocot order Zingiberales.

Early floral development of Heliconia latispatha (Heliconiaceae), a key taxon for understanding the evolution of flower development in the Zingiberales.

We present new comparative data on early floral development of Heliconia latispatha, an ecologically and horticulturally important tropical plant within the order Zingiberales. Modification of the six members of two androecial whorls is characteristic of Zingiberales, with a reduction in number of fertile stamen from five or six in the banana families (Musaceae, Strelitziaceae, Lowiaceae, and Heliconiaceae) to one in Costaceae and Zingiberaceae and one-half in Marantaceae and Cannaceae. The remaining five infertile stamens in these later four families (the ginger families) are petaloid, and in Costaceae and Zingiberaceae fuse together to form a novel structure, the labellum.

Epi-illumination microscopy coupled to in situ hybridization and its utility in the study of evolution and development in non-model species.

Evolutionary developmental biology often combines methods for examining morphology (e.g., scanning electron microscopy, SEM) with analyses of gene expression (e.