SECONDARY CLASSROOM VOCABULARY: DATA FROM TYPICALLY DEVELOPING STUDENTS

Students who use augmentative and alternative communication (AAC) need access to specific vocabulary to participate fully in general education classrooms. To date, there is no research on the vocabulary used in secondary level classrooms. In this study, the vocabulary used by 39 naturally speaking students in 5 secondary level general education classrooms was recorded and analyzed. Teacher vocabulary predictions for each class were collected and compared to recorded vocabulary use. Number of different words used, use of core vs. fringe vocabulary, and teacher prediction abilities varied widely according to several variables including instructional format, subject area, and grade level. Findings suggest higher lexical diversity in non-lecture-based classes and a higher proportion of fringe vocabulary use in social studies courses. More effective teacher prediction appears to be correlated with inclusion of non-curricular fringe terms and use of non-lecture-based instructional formats. These findings illustrate the fact AAC vocabulary use in secondary classrooms is complex and influenced by numerous factors, and the exact nature of these relationships may be clarified by further research. Teacher prediction appears to be a more effective vocabulary selection method for non-lecture-based classes, though further research is needed to confirm this finding

A gene encoding a SHINE1/WAX INDUCER1 transcription factor controls cuticular wax in barley

All land plants seal their above ground body parts with a lipid-rich hydrophobic barrier called the cuticle to protect themselves from dehydration and other terrestrial threats. Mutational studies in several model species have identified multiple loci regulating cuticular metabolism and development. Of particular importance are the eceriferum (cer) mutants characterized by a loss of cuticular wax. Some barley cer mutants, including cer-x, show defects in the distinctive β-diketone-enriched wax bloom on reproductive stage leaf sheaths, stems, and spikes. We exploited extensive allelic populations, near-isogenic lines, and powerful genotyping platforms to identify variation in the HvWAX INDUCER1 (HvWIN1) gene, encoding a SHINE transcription factor, as underlying cer-x. Comparing the cer-x allelic glossy sheath4.l Bowman Near Isogenic Line BW407 to cv. Bowman revealed an increased cuticular permeability in tissues showing reduced accumulation of β-diketones and altered cuticular metabolic gene expression in BW407. Analyses across the barley pangenome and hundreds of exome-capture datasets revealed high sequence conservation of HvWIN1 and two non-synonymous variants exclusive to the cultivated germplasm. Taken together, we suggest that variation in HvWIN1 controls multiple cuticular features in barley

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Seasonal regulation of petal number

International audienceFour petals characterize the flowers of most species in the Brassicaceae family, and this phenotype is generally robust to genetic and environmental variation. A variable petal number distinguishes the flowers of Cardamine hirsuta from those of its close relative Arabidopsis (Arabidopsis thaliana), and allelic variation at many loci contribute to this trait. However, it is less clear whether C. hirsuta petal number varies in response to seasonal changes in environment. To address this question, we assessed whether petal number responds to a suite of environmental and endogenous cues that regulate flowering time in C. hirsuta. We found that petal number showed seasonal variation in C. hirsuta, such that spring flowering plants developed more petals than those flowering in summer. Conditions associated with spring flowering, including cool ambient temperature, short photoperiod, and vernalization, all increased petal number in C. hirsuta. Cool temperature caused the strongest increase in petal number and lengthened the time interval over which floral meristems matured. We performed live imaging of early flower development and showed that floral buds developed more slowly at 15°C versus 20°C. This extended phase of floral meristem formation, coupled with slower growth of sepals at 15°C, produced larger intersepal regions with more space available for petal initiation. In summary, the growth and maturation of floral buds is associated with variable petal number in C. hirsuta and responds to seasonal changes in ambient temperature

Conserved signalling components coordinate epidermal patterning and cuticle deposition in barley

Faced with terrestrial threats, land plants seal their aerial surfaces with a lipid-rich cuticle. To breathe, plants interrupt their cuticles with adjustable epidermal pores, called stomata, that regulate gas exchange, and develop other specialised epidermal cells such as defensive hairs. Mechanisms coordinating epidermal features remain poorly understood. Addressing this, we studied two loci whose allelic variation causes both cuticular wax-deficiency and misarranged stomata in barley, identifying the underlying genes, Cer-g/ HvYDA1, encoding a YODA-like (YDA) MAPKKK, and Cer-s/ HvBRX-Solo, encoding a single BREVIS-RADIX (BRX) domain protein. Both genes control cuticular integrity, the spacing and identity of epidermal cells, and barley’s distinctive epicuticular wax blooms, as well as stomatal patterning in elevated CO(2) conditions. Genetic analyses revealed epistatic and modifying relationships between HvYDA1 and HvBRX-Solo, intimating that their products participate in interacting pathway(s) linking epidermal patterning with cuticular properties in barley. This may represent a mechanism for coordinating multiple adaptive features of the land plant epidermis in a cultivated cereal

<i>APETALA2</i> functions as a temporal factor together with <i>BLADE-ON-PETIOLE2</i> and <i>MADS29</i> to control flower and grain development in barley

Cereal grain develops from fertilised florets. Alterations in floret and grain development greatly influence grain yield and quality. Despite this, little is known about the underlying genetic control of these processes, especially in key temperate cereals such as barley and wheat. Using a combination of near-isogenic mutant comparisons, gene editing and genetic analyses, we reveal that HvAPETALA2 (HvAP2) controls floret organ identity, floret boundaries, and maternal tissue differentiation and elimination during grain development. These new roles of HvAP2 correlate with changes in grain size and HvAP2-dependent expression of specific HvMADS-box genes, including the B-sister gene, HvMADS29 Consistent with this, gene editing demonstrates that HvMADS29 shares roles with HvAP2 in maternal tissue differentiation. We also discovered that a gain-of-function HvAP2 allele masks changes in floret organ identity and grain size due to loss of barley LAXATUM.A/ BLADE-ON-PETIOLE2 (HvBOP2) gene function. Taken together, we reveal novel, pleiotropic roles and regulatory interactions for an APETALA2-like gene controlling floret and grain development in a temperate cereal.Jennifer R. Shoesmith, Charles Ugochukwu Solomon, Xiujuan Yang, Laura G. Wilkinson, Scott Sheldrick, Ewan van Eijden ... et al

Conservation versus divergence in LEAFY and APETALA functions between Arabidopsis thaliana and Cardamine hirsuta

International audienceA conserved genetic toolkit underlies the development of diverse floral forms among angiosperms. However, the degree of conservation vs divergence in the configuration of these gene regulatory networks is less clear. We addressed this question in a parallel genetic study between the closely related species Arabidopsis thaliana and Cardamine hirsuta. We identified leafy (lfy) and apetala1 (ap1) alleles in a mutant screen for floral regulators in C. hirsuta. C. hirsuta lfy mutants showed a complete homeotic conversion of flowers to leafy shoots, mimicking lfy ap1 double mutants in A. thaliana. Through genetic and molecular experiments, we showed that AP1 activation is fully dependent on LFY in C. hirsuta, by contrast to A. thaliana. Additionally, we found that LFY influences heteroblasty in C. hirsuta, such that loss or gain of LFY function affects its progression. Overexpression of UNUSUAL FLORAL ORGANS also alters C. hirsuta leaf shape in an LFY-dependent manner. We found that LFY and AP1 are conserved floral regulators that act nonredundantly in C. hirsuta, such that LFY has more obvious roles in floral and leaf development in C. hirsuta than in A. thaliana