Transcriptome analyses of leaf architecture in support a common genetic toolkit in the parallel evolution of unifacial leaves in monocots.

Planar structures dramatically increase the surface-area-to-volume ratio, which is critically important for multicellular organisms. In this study, we utilize naturally occurring phenotypic variation among three species (Asperagaceae) to investigate leaf margin expression patterns that are associated with mediolateral and adaxial/abaxial development. We identified differentially expressed genes (DEGs) between center and margin leaf tissues in two planar-leaf species and and compared these with expression patterns within the cylindrically leaved .

Optimization and application of non-native Phragmites australis transcriptome assemblies.

Phragmites australis (common reed) has a cosmopolitan distribution and has been suggested as a model organism for the study of invasive plant species. In North America, the non-native subspecies (ssp. australis) is widely distributed across the contiguous 48 states in the United States and large parts of Canada.

Utilizing multiplex fluor LAMPs to illuminate multiple gene expressions in situ.

In situ gene expression detection is the best way to determine temporal and spatial differences in gene expression. However, in situ hybridization procedures are inherently difficult to execute and typically suffer from degradation of sample tissues, limited sensitivity to genes with low expression, high background, and limitation to single gene detections. We propose to utilize an isothermal gene amplification technique, LAMP (Loop-Mediated Isothermal Amplification), to solve these problems in a novel way.

Gender-specific expression of GIBBERELLIC ACID INSENSITIVE is critical for unisexual organ initiation in dioecious Spinacia oleracea.

While unisexual flowers have evolved repeatedly throughout angiosperm families, the actual identification of sex-determining genes has been elusive, and their regulation within populations remains largely undefined. Here, we tested the mechanism of the feminization pathway in cultivated spinach (Spinacia oleracea), and investigated how this pathway may regulate alternative sexual development. We tested the effect of gibberellic acid (GA) on sex determination through exogenous applications of GA and inhibitors of GA synthesis and proteasome activity.

Following Darwin's trail: interactions affecting the evolution of plant mating systems.

• Since the time of Charles Darwin, the variation in floral characteristics and its effects on plant mating system evolution have fascinated scientists. Recent advances in the field of genetics, molecular biology, and ecology have been very effective in addressing questions regarding mechanisms and interactions underlying the evolution of plant mating systems using various model and nonmodel species. The depth of plant mating system research reflects the complexity and diversity seen in nature, ranging from self-compatible hermaphroditic flowers to separate sexed individuals.

Hormonal interactions and gene regulation can link monoecy and environmental plasticity to the evolution of dioecy in plants.

Most models for dioecy in flowering plants assume that dioecy arises directly from hermaphroditism through a series of independent feminizing and masculinizing mutations that become chromosomally linked. However, dioecy appears to evolve most frequently through monoecious grades. The major genetic models do not explain the evolution of unisexual flowers in monoecious and submonoecious populations, nor do they account for environmentally induced sexual plasticity.

Multiple developmental processes underlie sex differentiation in angiosperms.

The production of unisexual flowers has evolved numerous times in dioecious and monoecious plant taxa. Based on repeated evolutionary origins, a great variety of developmental and genetic mechanisms underlying unisexual flower development is predicted. Here, we comprehensively review the modes of development of unisexual flowers, test potential correlations with sexual system, and end with a synthesis of the genetics and hormonal regulation of plant sex determination.

Functional analysis of B and C class floral organ genes in spinach demonstrates their role in sexual dimorphism.

Background: Evolution of unisexual flowers entails one of the most extreme changes in plant development. Cultivated spinach, Spinacia oleracea L., is uniquely suited for the study of unisexual flower development as it is dioecious and it achieves unisexually by the absence of organ development, rather than by organ abortion or suppression.

Duplication of AP1 within the Spinacia oleracea L. AP1/FUL clade is followed by rapid amino acid and regulatory evolution.

The AP1/FUL clade of MADS box genes have undergone multiple duplication events among angiosperm species. While initially identified as having floral meristem identity and floral organ identity function in Arabidopsis, the role of AP1 homologs does not appear to be universally conserved even among eudicots. In comparison, the role of FRUITFULL has not been extensively explored in non-model species.

Sequence evolution and sex-specific expression patterns of the C class floral identity gene, SpAGAMOUS, in dioecious Spinacia oleracea L.

Development in dioecious cultivated spinach, Spinacia oleracea, is distinguished by the absence of alternative reproductive organ primordia in male and female flowers. Given the highly derived floral developmental program in spinach, we wished to characterize a spinach C class floral identity gene and to determine the patterns of sequence evolution as well as compare the spatial and temporal expression patterns with those of AGAMOUS. The isolated cDNA sequence clusters phylogenetically within the AGAMOUS/FARINELLI C class clade.

Characterization of SpAPETALA3 and SpPISTILLATA, B class floral identity genes in Spinacia oleracea, and their relationship to sexual dimorphism.

Floral organ identity B class genes are generally recognized as being required for development of petals and stamens in angiosperm flowers. Spinach flowers are distinguished in their complete absence of petals in both sexes, and the absence of a developed stamen whorl in female flowers. As such, we hypothesized that differential expression of B class floral identity genes is integral to the sexual dimorphism in spinach flowers.

Genes affecting aging: mapping quantitative trait loci in Drosophila melanogaster using amplified fragment length polymorphisms (AFLPs).

This study examines the use of AFLPs (amplified fragment length polymorphisms) for locating QTL for longevity. Inbred long and short-lived lines from selected stocks of D. melanogaster were backcrossed and measurements of life span compiled into a distribution.

EVOLUTIONARY ANALYSIS OF THE LARGE SUBUNIT OF CARBOXYLASE (rbcL) NUCLEOTIDE SEQUENCE AMONG THE GRASSES (GRAMINEAE).

The full nucleotide sequences of the chloroplast encoded large subunit of ribulose-1,5-bisphosphate carboxylase (rbcL) are available for nine grass species and partial sequence data for one species. Relative rate tests of the "molecular clock" hypothesis suggest that rbcL evolved more rapidly in the lineage leading to Zea than in those leading to the other species. The estimated overall substitution rate for rbcL among these grasses is about 5 times 10 substitutions per site per year, or about one-half the synonymous rate.

MIGRATION PATTERNS AND THE DEVELOPMENT OF MULTILOCUS ASSOCIATIONS IN A SELFING ANNUAL, TRITICUM DICOCCOIDES.

Migration patterns in wild emmer wheat, Triticum dicoccoides, were inferred from single-locus and multilocus genetic distributions based primarily on expectations derived from single-locus and multilocus cline theory. Populations from five collections displayed a large amount of multilocus structuring, as indicated by high values of gametic-phase disequilibrium between pairs of loci and by high values of multilocus associations. Analyses of the distributions of individual alleles, however, indicated that alleles had apparent independent centers of origin and that at least some independent dispersal within regions occupied by ecotypes or races of wild emmer had occurred.

ESTIMATION OF GENE FLOW AND GENETIC NEIGHBORHOOD SIZE BY INDIRECT METHODS IN A SELFING ANNUAL, TRITICUM DICOCCOIDES.

Rates of gene flow and neighborhood area were investigated in the selfing annual, Triticum dicoccoides. The collection of seed material was made using a spatial hierarchical sampling design in which four collection sites were 5-7 m apart, four were 15-17 m apart, and four were 100-120 m apart. Between 25 and 30 plants were scored from each site (mean sample size = 28.

NATURAL SELECTION OF ALLOZYME POLYMORPHISMS: A MICROSITE TEST REVEALING ECOLOGICAL GENETIC DIFFERENTIATION IN WILD BARLEY.

Allozymic variation in proteins encoded by 25 loci was analyzed electrophoretically in 1982 and 1983 in 356 individual plants from a dense population of wild barley, Hordeum spontaneum, the progenitor of cultivated barley. The test involved six microniches organized in a mosaic pattern in the open Tabor oak forest at Neve Ya'ar, Israel. The microniches were i) sun-soil, ii) sun-rock, iii) shade-soil, iv) shade-rock, and the contact zones: v) soil periphery of the sun-rock microniche, and vi) soil periphery of the shade-rock microniche.