A regulatory network controlling developmental boundaries and meristem fates contributed to maize domestication.

During domestication, early farmers selected different vegetative and reproductive traits, but identifying the causative loci has been hampered by their epistasis and functional redundancy. Using chromatin immunoprecipitation sequencing combined with genome-wide association analysis, we uncovered a developmental regulator that controls both types of trait while acting upstream of multiple domestication loci. tasselsheath4 (tsh4) is a new maize domestication gene that establishes developmental boundaries and specifies meristem fates despite not being expressed within them.

Transcription factor binding site divergence across maize inbred lines drives transcriptional and phenotypic variation.

Regulatory elements are important constituents of plant genomes that have shaped ancient and modern crops. Their identification, function, and diversity in crop genomes however are poorly characterized, thus limiting our ability to harness their power for further agricultural advances using induced or natural variation. Here, we use DNA affinity purification-sequencing (DAP-seq) to map transcription factor (TF) binding events for 200 maize TFs belonging to 30 distinct families and heterodimer pairs in two distinct inbred lines historically used for maize hybrid plant production, providing empirical binding site annotation for 5.

QTL analysis of divergent floral morphology traits between Gilia yorkii and G. capitata.

Speciation is a complex process typically accompanied by significant genetic and morphological differences between sister populations. In plants, divergent floral morphologies and pollinator differences can result in reproductive isolation between populations. Here, we explore floral trait differences between two recently diverged species, Gilia yorkii and G.

Ontogeny and anatomy of Bouteloua (Poaceae: Chloridoideae) species display a basipetal branch formation and a novel modified leaf structure in grasses.

Background And Aims: Shoot ontogenesis in grasses follows a transition from a vegetative phase into a reproductive phase. Current studies provide insight into how branch and spikelet formation occur during the reproductive phase. However, these studies do not explain all the complex diversity of grass inflorescence forms and are mostly focused on model grasses.

Boundary domain genes were recruited to suppress bract growth and promote branching in maize.

Grass inflorescence development is diverse and complex and involves sophisticated but poorly understood interactions of genes regulating branch determinacy and leaf growth. Here, we use a combination of transcript profiling and genetic and phylogenetic analyses to investigate () and , two maize genes that simultaneously suppress inflorescence leaf growth and promote branching. We identify a regulatory network of inflorescence leaf suppression that involves the phase change gene upstream of and the ligule identity gene ().

Chromosome-Scale Genome Assembly of Gilia yorkii Enables Genetic Mapping of Floral Traits in an Interspecies Cross.

Substantial morphological variation in land plants remains inaccessible to genetic analysis because current models lack variation in important ecological and agronomic traits. The genus Gilia was historically a model for biosystematics studies and includes variation in morphological traits that are poorly understood at the genetic level. We assembled a chromosome-scale reference genome of G.

Recruitment of an ancient branching program to suppress carpel development in maize flowers.

Carpels in maize undergo programmed cell death in half of the flowers initiated in ears and in all flowers in tassels. The HD-ZIP I transcription factor gene () is one of only a few genes known to regulate this process. To identify additional regulators of carpel suppression, we performed a enhancer screen and found a genetic interaction between and ().

Integration of high-density genetic mapping with transcriptome analysis uncovers numerous agronomic QTL and reveals candidate genes for the control of tillering in sorghum.

Phenotypes such as branching, photoperiod sensitivity, and height were modified during plant domestication and crop improvement. Here, we perform quantitative trait locus (QTL) mapping of these and other agronomic traits in a recombinant inbred line (RIL) population derived from an interspecific cross between Sorghum propinquum and Sorghum bicolor inbred Tx7000. Using low-coverage Illumina sequencing and a bin-mapping approach, we generated ∼1920 bin markers spanning ∼875 cM.

Evolutionary Variation in MADS Box Dimerization Affects Floral Development and Protein Abundance in Maize.

Interactions between MADS box transcription factors are critical in the regulation of floral development, and shifting MADS box protein-protein interactions are predicted to have influenced floral evolution. However, precisely how evolutionary variation in protein-protein interactions affects MADS box protein function remains unknown. To assess the impact of changing MADS box protein-protein interactions on transcription factor function, we turned to the grasses, where interactions between B-class MADS box proteins vary.

Development of an Evolutionary Tree Concept Inventory.

Despite the importance of tree-thinking and evolutionary trees to biology, no appropriately developed concept inventory exists to measure student understanding of these important concepts. To address this need, we developed a multiple-choice concept inventory consisting of 24 pairs of items, and we provide evidence to support its use among undergraduate students. A set of learning outcomes was developed to guide the creation of the concept inventory.

The regulatory landscape of a core maize domestication module controlling bud dormancy and growth repression.

Many domesticated crop plants have been bred for increased apical dominance, displaying greatly reduced axillary branching compared to their wild ancestors. In maize, this was achieved through selection for a gain-of-function allele of the TCP transcription factor teosinte branched1 (tb1). The mechanism for how a dominant Tb1 allele increased apical dominance, is unknown.

Bulked-Segregant Analysis Coupled to Whole Genome Sequencing (BSA-Seq) for Rapid Gene Cloning in Maize.

Forward genetics remains a powerful method for revealing the genes underpinning organismal form and function, and for revealing how these genes are tied together in gene networks. In maize, forward genetics has been tremendously successful, but the size and complexity of the maize genome made identifying mutant genes an often arduous process with traditional methods. The next generation sequencing revolution has allowed for the gene cloning process to be significantly accelerated in many organisms, even when genomes are large and complex.

Grass inflorescence architecture and meristem determinacy.

The grass inflorescence is striking not only for its beauty and diversity, but also for its developmental complexity. While models of inflorescence architecture have been proposed in both eudicots and grasses, these are inadequate to fully explain the complex branching events that occur during the development of the grass inflorescence. Key to understanding grass inflorescence architecture is the meristem determinacy/indeterminacy decision, which regulates the number of branching events that occur.

Grass inflorescence architecture and evolution: the origin of novel signaling centers.

Contents 367 I. 367 II. 368 III.

Altered expression of maize PLASTOCHRON1 enhances biomass and seed yield by extending cell division duration.

Maize is the highest yielding cereal crop grown worldwide for grain or silage. Here, we show that modulating the expression of the maize PLASTOCHRON1 (ZmPLA1) gene, encoding a cytochrome P450 (CYP78A1), results in increased organ growth, seedling vigour, stover biomass and seed yield. The engineered trait is robust as it improves yield in an inbred as well as in a panel of hybrids, at several locations and over multiple seasons in the field.

Prevalence and Persistence of Misconceptions in Tree Thinking.

Darwin described evolution as "descent with modification." Descent, however, is not an explicit focus of most evolution instruction and often leaves deeply held misconceptions to dominate student understanding of common ancestry and species relatedness. Evolutionary trees are ways of visually depicting descent by illustrating the relationships between species and groups of species.

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.

Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein-Protein Interactions.

Protein-protein interactions (PPIs) have widely acknowledged roles in the regulation of development, but few studies have addressed the timing and mechanism of shifting PPIs over evolutionary history. The B-class MADS-box transcription factors, PISTILLATA (PI) and APETALA3 (AP3) are key regulators of floral development. PI-like (PI(L)) and AP3-like (AP3(L)) proteins from a number of plants, including Arabidopsis thaliana (Arabidopsis) and the grass Zea mays (maize), bind DNA as obligate heterodimers.

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.

Positional cloning in maize (Zea mays subsp. mays, Poaceae).

Premise Of The Study: Positional (or map-based) cloning is a common approach to identify the molecular lesions causing mutant phenotypes. Despite its large and complex genome, positional cloning has been recently shown to be feasible in maize, opening up a diverse collection of mutants to molecular characterization. •

Methods And Results: Here we outline a general protocol for positional cloning in maize.

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.

Early inflorescence development in the grasses (Poaceae).

The shoot apical meristem of grasses produces the primary branches of the inflorescence, controlling inflorescence architecture and hence seed production. Whereas leaves are produced in a distichous pattern, with the primordia separated from each other by an angle of 180°, inflorescence branches are produced in a spiral in most species. The morphology and developmental genetics of the shift in phyllotaxis have been studied extensively in maize and rice.

From many, one: genetic control of prolificacy during maize domestication.

A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips.

grassy tillers1 promotes apical dominance in maize and responds to shade signals in the grasses.

The shape of a plant is largely determined by regulation of lateral branching. Branching architecture can vary widely in response to both genotype and environment, suggesting regulation by a complex interaction of autonomous genetic factors and external signals. Tillers, branches initiated at the base of grass plants, are suppressed in response to shade conditions.