BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

Ectopic expression of the Brassica napus BABY BOOM (BBM) AP2/ERF transcription factor is sufficient to induce spontaneous cell proliferation leading primarily to somatic embryogenesis, but also to organogenesis and callus formation. We used DNA microarray analysis in combination with a post-translationally regulated BBM:GR protein and cycloheximide to identify target genes that are directly activated by BBM expression in Arabidopsis seedlings. We show that BBM activated the expression of a largely uncharacterized set of genes encoding proteins with potential roles in transcription, cellular signaling, cell wall biosynthesis and targeted protein turnover. A number of the target genes have been shown to be expressed in meristems or to be involved in cell wall modifications associated with dividing/growing cells. One of the BBM target genes encodes an ADF/cofilin protein, ACTIN DEPOLYMERIZING FACTOR9 (ADF9). The consequences of BBM:GR activation on the actin cytoskeleton were followed using the GFP:FIMBRIN ACTIN BINDING DOMAIN2 (GFP:FABD) actin marker. Dexamethasone-mediated BBM:GR activation induced dramatic changes in actin organization resulting in the formation of dense actin networks with high turnover rates, a phenotype that is consistent with cells that are rapidly undergoing cytoplasmic reorganization. Together the data suggest that the BBM transcription factor activates a complex network of developmental pathways associated with cell proliferation and growth

Meat trays, marginalisation and the mechanisms of social capital creation: An ethnographic study of a licensed social club and its older users

Alongside informal networks of friends and family, formal social groupings such as voluntary associations are valued by older people as opportunities for engagement. In Australia, one such grouping is the licensed social (or ‘registered’) club. Approximately 20 per cent of all older Australians, and 80 per cent of older residents of the state of New South Wales, actively participate in such clubs. Despite this, older people’s registered club participation has received little scholarly attention. This ethnographic study of one particular registered club aimed to discover the nature, meaning and role of club participation for its older members. Social capital existing in club-based networks emerged as a further investigative focus, and its mechanisms and outcomes were examined. Participant observation and in-depth interviewing were the main data collection methods used. Data analysis procedures included thematic analysis (based loosely on grounded theory methodology), as well as the more contextsensitive narrative analysis and key-words-in-context analysis. The study found that club participation enabled older members to maintain valued social networks, self-reliance and a sense of autonomy. Social networks were characterised by social capital of the bonding type, being largely homogeneous with respect to age, gender, (working) class and cultural background. Strong cohesive bonds were characterised by intimacy and reciprocity, and possessed norms including equality and the norm of tolerance and inclusiveness. These helped to minimise conflict and build cohesiveness, while protecting older club-goers from increasing marginalisation within the club. Peer grouping within this mainstream setting may have shielded the older club-goers from stigma associated with participation in old-age specific groups. The nature and scale of registered club participation amongst older Australians points to their unique and important role. The findings of this research indicate that – for at least this group of older men and women - club use is a major contributor to maintaining social connectedness and a sense of self as self-reliant, autonomous and capable. In the context of an ageing population, Australia’s registered clubs feature in the mosaic of resources available to older people, and their communities, for the creation of social capital

Genomic cloning and linkage mapping of the Mal d 1 (PR-10) gene family in apple (Malus domestica)

Fresh apples can cause birch pollen-related food allergy in northern and central European populations, primarily because of the presence of Mal d 1, the major apple allergen that is cross-reactive to the homologous and sensitizing allergen Bet v 1 from birch. Apple cultivars differ significantly in their allergenicity. Knowledge of the genetic basis of these differences would direct breeding for hypoallergenic cultivars. The PCR genomic cloning and sequencing were performed on two cultivars, Prima and Fiesta, which resulted in 37 different Mal d 1 gDNA sequences. Based on the mapping of sequence-specific molecular markers, these sequences appeared to represent 18 Mal d 1 genes. Sixteen genes were located in two clusters, one cluster with seven genes on linkage group (LG) 13, and the other cluster with nine genes on the homoeologous LG 16. One gene was mapped on LG 6, and one remained unmapped. According to sequence identity, these 18 genes could be subdivided into four subfamilies. Subfamilies I–III had an intron of different size that was subfamily and gene-specific. Subfamily IV consisted of 11 intronless genes. The deduced amino acid sequence identity varied from 65% to 81% among subfamilies, from 82% to 100% among genes within a subfamily, and from 97.5% to 100% among alleles of one gene. This study provides a better understanding of the genetics of Mal d 1 and the basis for further research on the occurrence of allelic diversity among cultivars in relation to allergenicity and their biological functions

Seed genomics: germinating opportunities

With the sequencing of the Arabidopsis thaliana genome, the field of plant biology has made a quantum leap. The sequence information available to the community has greatly facilitated the identification of genes responsible for mutant phenotypes and the large-scale analysis of gene expression in Arabidopsis. High-throughput laboratory tools for DNA sequencing (genomics), mutant analysis (functional genomics), mRNA quantification (transcriptomics) and protein analysis (proteomics) are being used to scrutinize this model plant. For seed physiologists, the challenge lies in translating this information into physiological processes in seeds from other plant species. Combining more traditional seed biology with the new high-throughput molecular tools should yield breakthroughs in seed science

Methods and means for determining and conferring stress tolerance in plants

The current invention provides a method for rapid testing of stress tolerance in a plant and a method of producing plants with enhanced stress tolerance, in particular cold and/or drought tolerance. Such a method may be applied in breeding and selection programs for this trait, or for determining the timing of induction of stress and cold tolerance or hardening of a plant, for instance for agricultural purposes. The current invention exploits a difference in the temperature and light regimen induced transcriptional regulation of several types of dehydrins, in order to determine a ratio of dehydrin types that is indicative of cold and/or drought tolerance, induction of hardening and dormancy in a plant

Gene expression in relation to seed development and longevity

During maturation seeds acquire stress tolerance and increase in longevity, which are lost completely or partially during germination and priming. Slow drying can partly restore the longevity of primed seeds. Cabbage (Brassica oleracea L.) seeds were used as a model to analyse expression of genes during these processes. Six genes for which the expression profiles correlated with the longevity level were identified. Two of these genes are discussed in more detail, EM6 and RAB18, next to the kinetics of two cell cycle genes, historic H1-1 and histone H3. These genes, and the proteins they encode, might serve as markers for optimization of seed processing protocols to produce seeds with a high level of longevity

Methods and means for determining and conferring stress tolerance in plants

The current invention provides a method for rapid testing of stress tolerance in a plant and a method of producing plants with enhanced stress tolerance, in particular cold and/or drought tolerance. Such a method may be applied in breeding and selection programs for this trait, or for determining the timing of induction of stress and cold tolerance or hardening of a plant, for instance for agricultural purposes. The current invention exploits a difference in the temperature and light regimen induced transcriptional regulation of several types of dehydrins, in order to determine a ratio of dehydrin types that is indicative of cold and/or drought tolerance, induction of hardening and dormancy in a plant

Gene expression during loss and regaining of stress tolerance at seed priming and drying.

This chapter discusses the gene expression under stress tolerance and in the absence of stress tolerance at seed priming and drying. An experimental model set up using cabbage seeds of different physiological qualities is described. The topics discussed include: effects of priming on germination rate and storability; sensitivity to ultra-drying; seed maturity; and gene expression studies using cDNA microarrays