Systemic and local responses to repeated HL stress-induced retrograde signaling in Arabidopsis

Chloroplasts of leaves under high light stress initiate signals to the nuclei of both exposed and distal leaves in order to acclimate against the potential threat of oxidative damage: a process known as high light systemic acquired acclimation (HL SAA). This study explores the nature of HL SAA, synergistic interactions with other environmental stresses, and the impact of repeated HL stress on the acclimation response of exposed and distal leaves. This necessitated the development of novel experimental systems to investigate the initiation, perception, and response to HL SAA. These systems were used to investigate the HL SAA response by monitoring the induction of mRNA in distal leaves not exposed to the HL stress. Acclimation to HL is induced within minutes and the response is proportionally dependent on the quality and quantity of light. HL SAA treatments in conjunction with variations in temperature and humidity reveal HL SAA is influenced by fluctuations in humidity. These treatments also result in changes in auxin accumulation and auxin-responsive genes. A key question in retrograde signaling is the extent to which transient changes in light intensity result in a "memory" of the event leading to acclimation responses. Repeated exposure to short term HL resulted in acclimation of the exposed tissue and that of emerging and young leaves (but not older leaves) to HL and oxidative stress

Framing best practice: National Standards for the primary prevention of sexual assault through education (National Sexual Assault Prevention Education Project for NASASV)

In 2008, the Rudd Labor Government identified the prevention of violence against women as a priority for action. The National Sexual Assault Prevention Education Research Project (SAPE) was established to complete a one-year project to develop and trial a national sexual assault prevention education framework. The project was to identify best or promising practice models for doing sexual assault prevention education in the Australian context with the aim of building upon existing prevention education activities to provide a framework that can be implemented across Australia by prevention educators, service providers, policy makers and funding bodies. In considering existing prevention programs the following areas were of particular interest: programs that have incorporated men as well as women, that are targeted to culturally and sexually diverse groups, and that address the specific needs of regional women and men and people with disabilities. Another key component of the consultation process was to identify programs that included some form of evaluation, particularly programs that have included steps toward assessing behavioural change. In addition, the research was to identify some of the barriers to wider implementation of primary sexual assault prevention education. This report provides a comprehensive discussion of the research underpinning the framework, along with some of the researchers' analysis of the 32 fieldwork interviews that were completed with workers and other key individuals in most states in Australia. Six national standards for sexual assault prevention education are identified and described as the framework for increasing the capacity of the sector to deliver high quality primary prevention education programs

Rapid Leaf-to-leaf communication of high light stress in Arabidopsis

Two models have recently been proposed to explain systemic abiotic stress signaling in Arabidopsis: the idea of a cell-to-cell autonomous system within an individual leaf, as well as an algorithmic model of intercellular signaling functioning as a whole-plant stress signaling network. Both models assume a universal stress signaling mechanism that acts via plasma membrane-bound NADPH-oxidases to induce apoplastic H2O2 in order to signal to neighbouring cells. These models are problematic, however, as they do not address the idea of stress specificity which is currently believed to be perceived by a plant based on the induction of compartment-specific ROS induced by individual types of stress. They also do not address how, and in what form, a signal can travel from a stressed leaf via the vascular to another leaf within the rosette. Additional problems are that even in studies that focus on a specific stress such as HL, results cannot be consolidated due to experimental differences in light intensity, duration, and tissue sampling. This study focuses on rapid systemic HL signaling, known as Systemic Acquired Acclimation (SAA). The major strategy in studying this signal was to observe the behaviour of the signal from two different points in the pathway: (1) investigation into the initiation of SAA through perception of HL as well as identification of chloroplast to nucleus retrograde signaling pathways, and (2) investigation of what is required for the long distance relay of the signal from leaf-to-leaf. These aims were achieved through spatial and temporal investigation of the immediate HL stress events in local and distal tissue and investigation of compartment-specific ROS production and signaling. Results revealed leaf-age dependant differences in oxidative stress tolerance across the rosette, justifying consistent leaf sampling, and that SAA confers uniform HL tolerance across the rosette for up to 12 h. There was also a strong indication that both H2O2 and 1O2 production in the chloroplast are required for initiation of SAA, and that extracellular H2O2 is necessary for distal induction of SAA responses, as this was blocked in the rbohD/F NADPH-oxidase mutant. While the presence of EX1/2 1O2-specific retrograde signaling appeared to be required for nuclear induction of SAA genes, both antagonistic and synergistic effects of chloroplast-generated ROS were also apparent. This indicates the existence of a highly complex ROS regulatory system within the chloroplast that does not strictly follow the general view that 1O2 promotes cell death, while H2O2 is required for acclimation. This study further improves our understanding of how environmentally-sensed signals can move rapidly through a plant undergoing localised HL stress in order to induce immediate systemic acclimation. Speculative assessment of these new findings alongside other recent publications subsequently reveals further possibilities of investigation into SAA with the hypothesis that rapid volatile signals induce specific distal stress responses, followed by slower more general stress vascular signals through the phloem

Transcriptional Control of SET DOMAIN GROUP 8 and CAROTENOID ISOMERASE during Arabidopsis Development

Carotenoids are pigments required for photosynthesis, photoprotection and the production of carotenoid-derived hormones such as ABA and strigolactones. The carotenoid biosynthetic pathway bifurcates after lycopene to produce epsilon- and beta-carotenoid

Systemic and local responses to repeated HL stress-induced retrograde signaling in Arabidopsis

Chloroplasts of leaves under high light stress initiate signals to the nuclei of both exposed and distal leaves in order to acclimate against the potential threat of oxidative damage: a process known as high light systemic acquired acclimation (HL SAA). This study explores the nature of HL SAA, synergistic interactions with other environmental stresses, and the impact of repeated HL stress on the acclimation response of exposed and distal leaves. This necessitated the development of novel experimental systems to investigate the initiation, perception and response to HL SAA. These systems were used to investigate the HL SAA response by monitoring the induction of mRNA in distal leaves not exposed to the HL stress. Acclimation to HL is induced within minutes and the response is proportionally dependent on the quality and quantity of light. HL SAA treatments in conjunction with variations in temperature and humidity reveal HL SAA is influenced by fluctuations in humidity. These treatments also result in changes in auxin accumulation and auxin-responsive genes. A key question in retrograde signaling is the extent to which transient changes in light intensity result in a memory of the event leading to acclimation responses. Repeated exposure to short term HL resulted in acclimation of the exposed tissue and that of emerging and young leaves (but not older leaves) to HL and oxidative stress

Biosynthesis and Regulation of Carotenoids in Plants- Micronutrients, Vitamins and Health Benefits

Carotenoids are a major class of natural, coloured pigments, ranging from the yellow, orange and red of many fruits, vegetables, flowers and autumn leaves, through to the colours of butterflies and crayfish. The bright colours of carotenoid pigments attract insects for pollination and dispersal of seeds, which are essential for reproduction. Carotenoids are essential components of the photosynthetic machinery, involved in the assembly of the photosystems, light-harvesting and photoprotection. They are the second most abundant pigment in nature and provide substrate derivatives for the production of phytohormones, such as abscisic acid and strigolactones. Fruits and vegetables are an essential dietary requirement for humans and provide carotenoid-derived micronutrients which promote health benefits including antioxidant activity, precursors for vitamin A biosynthesis, and prevention of macular degeneration. The main focus of this chapter is directed towards the biosynthesis, regulation, function and manipulation of carotenoid-derived micronutrients in plants and their benefits in human health

Driving with dementia: a shared decision approach to planning for driving retirement

Abstract presented at the 11th International Association of Gerontology and Geriatrics Asia/Oceania Regional Congress, 23-27 October 2019, Taipei, Taiwa

Framing best practice: national standards for the primary prevention of sexual assault through education

In 2008, the Rudd Labor Government identified the prevention of violence against women as a priority for action. The National Sexual Assault Prevention Education Research Project (SAPE) was established to complete a one-year project to develop and trial a national sexual assault prevention education framework. The project was to identify best or promising practice models for doing sexual assault prevention education in the Australian context with the aim of building upon existing prevention education activities to provide a framework that can be implemented across Australia by prevention educators, service providers, policy makers and funding bodies. In considering existing prevention programs the following areas were of particular interest: programs that have incorporated men as well as women, that are targeted to culturally and sexually diverse groups, and that address the specific needs of regional women and men and people with disabilities. Another key component of the consultation process was to identify programs that included some form of evaluation, particularly programs that have included steps toward assessing behavioural change. In addition, the research was to identify some of the barriers to wider implementation of primary sexual assault prevention education. This report provides a comprehensive discussion of the research underpinning the framework, along with some of the researchers' analysis of the 32 fieldwork interviews that were completed with workers and other key individuals in most states in Australia. Six national standards for sexual assault prevention education are identified and described as the framework for increasing the capacity of the sector to deliver high quality primary prevention education programs