Ros Gleadow

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• PhD (Botany) The University of Melbourne
• Emerita Professor at Monash University (Australia)

The use of high-throughput phenotyping systems and non-destructive imaging is widely regarded as a key technology allowing scientists and breeders to develop crops with the ability to perform well under diverse environmental conditions. However, many of these phenotyping studies have been optimized using the model plant Arabidopsis thaliana. In thi...

Cyanogenesis is the process by which plantsrelease hydrogen cyanide (HCN) from endogenous cyanide-containing compoundsand is thought to play a role in plant defence against generalist herbivores.Cyanogenesis is poorly understood in natural populations, and has been littlestudied in tree species. In this paper we present the first systematic surveyo...

The release of hydrogen cyanide from endogenous cyanide-containing compounds in plants is an effective herbivore deterrent. We investigated temporal and spatial variations in cyanogenic glycoside concentration in greenhouse-grown seedlings and 6-year-old plantation trees of Eucalyptus cladocalyx F. Muell., which allocates up to 20% of leaf nitrogen...

* Here, a new approach to macromolecular imaging of leaf tissue using a multichannel focal plane array (FPA) infrared detector was compared with the proven method of infrared mapping with a synchrotron source, using transverse sections of leaves from a species of Eucalyptus. * A new histological method was developed, ideally suited to infrared spec...

In this study approximately 420 of the described species of Eucalyptus were examined for cyanogenesis. Our work has identified an additional 18 cyanogenic species, 12 from living tissues and a further six from herbarium samples. This brings the total of known cyanogenic species to 23, representing approximately 4% of the genus. The taxonomic distri...

Moderately saline water has been proposed as a potential irrigation resource for crops such as forage sorghum ( Sorghum bicolor × Sorghum bicolor nothosubsp. drummondii ) in drought‐prone regions. However, it is not yet fully understood how salinity affects growth and potential toxicity of sorghum. Sorghum produces the cyanogenic glucoside dhurrin,...

Societal Impact Statement With global weather patterns becoming more extreme and unpredictable, sourcing reliable irrigation water is vital for improving food security and conserving drinking water in drought‐prone areas. Emerging desalination technologies, which are still in the development phase, could potentially provide large quantities of slig...

Cyanogenic glucosides are specialized metabolites produced by over 3000 species of higher plants from more than 130 families. The deployment of cyanogenic glucosides is influenced by biotic and abiotic factors in addition to being developmentally regulated, consistent with their roles in plant defense and stress mitigation. Despite their ubiquity,...

Context Wild sorghum taxa (Sorghum Moench) cover much of the northern Australian landscape and harbour potentially useful traits for crop improvement. Specialised metabolites such as phenolics, silicon and cyanogenic glucosides (which are toxic to grazing animals) are present in Sorghum and have been associated with drought tolerance. However, thes...

The cyanogenic glucoside, dhurrin, present in Sorghum bicolor is thought to have multiple functions, including in defence against herbivory. The hormone methyl jasmonate (MeJA) is also induced by herbivory and is key to instigating defence processes in plants. To investigate whether dhurrin is induced in response to herbivore attack and also to the...

Climate change is a driver of biodiversity loss, often favouring invasive species such as in the case of Pittosporum undulatum in Eucalyptus forests of south-eastern Australia. We tested whether the invasiveness of P. undulatum is due to the release of secondary metabolites with allelopathic action inhibiting other species germination or to the con...

Grain size and weight are two of the most important determinants of crop yield. Key genes associated with the grain size and weight have been identified in major crops. However, studies on the genetic basis of the grain size and weight related genes in wild Sorghum are limited. In this study, we analysed the variation of grain size related genes us...

Alpine plants in Australia are increasingly exposed to more frequent drought and heatwaves, with significant consequences for physiological stress responses. Acclimation is a critical feature that allows plants to improve tolerance to environmental extremes by directly altering their physiology or morphology. Yet it is unclear how plant performance...

• Domesticated sorghum (Sorghum bicolor [L.] Moench subsp. bicolor) diverts significant amounts of nitrogen away from primary metabolism to the synthesis of cyanogenic glucosides (CNglc) – specialized metabolites that release toxic hydrogen cyanide (HCN). Our aim was to identify the point in the genus Sorghum Moench at which plants gained the abili...

In 2009, Food Standards Australia New Zealand set a total cyanide content limit of 10 ppm for ready-to-eat cassava products to address food safety concerns about cyanogenic glucosides in cassava. This study surveys a range of cassava food products available in Melbourne, Australia, ten years after the implementation of these regulations. Of all the...

Main conclusion Droughted sorghum had higher concentrations of ROS in both wildtype and dhurrin-lacking mutants. Dhurrin increased in wildtype genotypes with drought. Dhurrin does not appear to mitigate oxidative stress in sorghum. Abstract Sorghum bicolor is tolerant of high temperatures and prolonged droughts. During droughts, concentrations of...

Alpine plants in Australia are increasingly exposed to more frequent drought and heatwaves, with significant consequences for physiological stress responses. Acclimation is a critical feature that allows plants to improve tolerance to environmental extremes through directly altering their physiology or morphology. Yet it is unclear how plant perfor...

Geographical variation in the environment underpins selection for local adaptation and evolutionary divergence among populations. Because many environmental conditions vary across species' ranges, identifying the specific environmental variables underlying local adaptation is profoundly challenging. We tested whether natural selection mediated by a...

Main conclusion Australian native species of sorghum contain negligible amounts of dhurrin in their leaves and the cyanogenesis process is regulated differently under water-stress in comparison to domesticated sorghum species. Abstract Cyanogenesis in forage sorghum is a major concern in agriculture as the leaves of domesticated sorghum are potent...

Domestication has resulted in a loss of genetic diversity in our major food crops, leading to susceptibility to biotic and abiotic stresses linked with climate change. Crop wild relatives (CWR) may provide a source of novel genes potentially important for re-gaining climate resilience. Sorghum bicolor is an important cereal crop with wild relatives...

Main conclusion Developmental and organ-specific expression of genes in dhurrin biosynthesis, bio-activation, and recycling offers dynamic metabolic responses optimizing growth and defence responses in Sorghum . Abstract Plant defence models evaluate the costs and benefits of resource investments at different stages in the life cycle. Poor underst...

Taro (Colocasia esculenta (L.) Schott) is a staple food crop in the Asia-Pacific region in areas where rising sea levels are threatening agricultural production. However, little is known about its response to salinity. In this study, we investigated the effects of salinity on the growth, morphology, physiology, and chemical traits of taro to predic...

Sorghum [Sorghum bicolor (L.) Moench] is an important food crop with a diverse gene pool residing in its wild relatives. A total of 15 sorghum accessions from the unexploited wild gene pool of the Sorghum genus, representing the five subgenera, were sequenced, and the complete chloroplast genomes and 99 common single‐copy concatenated nuclear genes...

Faunal responses to plant invasions and their managed removal can expand our understanding of the nature of disturbance and the success of restored plant communities. We examined how bird communities responded to the presence and removal of the invasive understorey tree Pittosporum undulatum Vent. (sweet pittosporum) in matched woodland areas in te...

Mycorrhizae can improve plant growth and drought tolerance by enhancing plant uptake of nutrients and water, which are important targets for biofilters, a common stormwater treatment system. This study evaluated the role of mycorrhizal inoculation on plant growth, photosynthetic efficiency and pollutant removal in two Australian plant species grown...

Domestication has narrowed the genetic diversity found in crop wild relatives, potentially reducing plasticity to cope with a changing climate. The tissues of domesticated sorghum (Sorghum bicolor), especially in younger plants, are cyanogenic and potentially toxic. Species of wild sorghum produce lower levels of the cyanogenic glucoside (CNglc) dh...

Crop plants are assumed to have become more susceptible to pests as a result of selection for high growth rates during the process of domestication, consistent with resource allocation theories. We compared the investment by domesticated sorghum into cyanogenic glucosides, nitrogen-based specialised metabolites that break down to release hydrogen c...

Natural variation of cyanogenic glycosides, soluble sugars, proline and nondestructive optical sensing of pigments (chlorophyll, flavonols and anthocyanins) were examined in ex situ natural populations of Eucalyptus cladocalyx F. Muell. grown under dry environmental conditions in the southern Atacama Desert, in Chile. After 18 consecutive dry seaso...

In plants, the production of secondary metabolites is considered to be at the expense of primary growth. Sorghum produces a cyanogenic glycoside (dhurrin) that is believed to act as its chemical defence. Studies have shown that acyanogenic plants are smaller in size compared to the wildtype. This study aimed to investigate whether the small plant s...

Cassava has the potential to alleviate food insecurity in many tropical regions, yet few breeding efforts to increase yield have been made. Improved photosynthetic efficiency in cassava has the potential to increase yields, but cassava roots must have sufficient sink strength to prevent carbohydrates from accumulating in leaf tissue and suppressing...

Aim To fill knowledge gaps regarding the distributions, ecogeographic niches and conservation status of sorghum's wild relatives (Sorghum Moench). Location The study covered the potential native ranges of wild Sorghum taxa worldwide, including Australia, New Guinea, Asia, Africa and Central America. Methods We modelled the distributions of 23 wil...

Sorghum bicolor (L.) Moench is a multipurpose food crop which is ranked among the top five cereal crops in the world, and is used as a source of food, fodder, feed, and fuel. The genus Sorghum consists of 24 diverse species. Cultivated sorghum was derived from the wild progenitor S. bicolor subsp. verticilliflorum, which is commonly distributed in...

Rising atmospheric CO2 concentrations and global warming can alter how plants partition their resources. This is important for food crops through changes in resource allocation to edible tissues and toxic defence compounds. While research suggests elevated temperature and [CO2] independently drive changes in plant metabolism and stress levels, and...

Dhurrin is the most abundant cyanogenic glucoside found in sorghum spp. (Sorghum bicolor) where it plays a key role in chemical defence by releasing toxic hydrogen cyanide upon tissue disruption. Besides this well-established function, there is strong evidence that dhurrin plays additional roles, e.g. as a transport and storage form of nitrogen, re...

Sorghum (Sorghum bicolor [L.] Moench) is a multipurpose food crop which is ranked among the top five cereal crops in the world. It serves as a source of food, fodder, feed and bioenergy. The genus Sorghum consists of 25 species and is considered as a group of plants with enormous diversity. Crop wild relatives have played significant roles in asses...

Sorghum bicolor (L.) Moench produces the nitrogen-containing natural product dhurrin that provides chemical defense against herbivores and pathogens via the release of toxic hydrogen cyanide gas. Drought can increase dhurrin in shoot tissues to concentrations toxic to livestock. As dhurrin is also a remobilizable store of reduced nitrogen and plays...

Food security and the sustainability of native ecosystems depends on plant-insect interactions in countless ways. Recently reported rapid and immense declines in insect numbers due to climate change, the use of pesticides and herbicides, the introduction of agricultural monocultures, and the destruction of insect native habitat, are all potential c...

[Draft] Sorghum bicolor is an important cereal crop grown in arid and semi-arid regions. Despite its high drought tolerance, S. bicolor is susceptible to severe drought, leading to a reduction in grain yield and plant biomass. In the leaves, drought also promotes accumulation of the cyanogenic glucoside dhurrin that gives rise to hydrogen cyanide r...

Sorghum bicolor produces the cyanogenic glucoside dhurrin, a secondary metabolite integral to plant defence and stress responses. Dhurrin production is both developmentally and environmentally regulated in S. bicolor, with high levels of variation within and between lines. Such phenotypic variation may result from polymorphic differences or epigene...

Most aerobic bacteria exist in dormant states within natural environments. In these states, they endure adverse environmental conditions such as nutrient starvation by decreasing metabolic expenditure and using alternative energy sources. In this study, we investigated the energy sources that support persistence of two aerobic thermophilic strains...

Aim Separation of regeneration niches may promote coexistence among closely related plant species, but there is little evidence that regeneration traits affect species ranges at broad geographical scales. We address patterns of co‐occurrence within the genus Selaginella, an ancient lineage of free‐sporing, heterosporous, vascular plants. Specifical...

Bacteria within aerated environments often exist within a variety of dormant forms. In these states, bacteria endure adverse environmental conditions such as organic carbon starvation by decreasing metabolic expenditure and using alternative energy sources. In this study, we investigated the energy sources that facilitate the persistence of the env...

Substantial research has been devoted to testing the potential for algal-derived biofuels. However, because of the high cost and low biomass productivity of algal mass culture, this is not yet a commercial reality. Most research has focused on optimizing photoautotrophic cultivation of algal biomass. Other modes of growing algae such as heterotroph...

Long-standing growth/defence theories state that the production of defence compounds come at a direct cost to primary metabolism when resources are limited. However, such trade-offs are inherently difficult to quantify. We compared the growth and nitrogen partitioning in wild type Sorghum bicolor (L.) Moench, which contains the cyanogenic glucoside...

Localisation of metabolites in sorghum coleoptiles using Raman hyperspectral imaging analysis was compared in wild type plants and mutants that lack cyanogenic glucosides. This novel method allows high spatial resolution in situ localization by detecting functional groups associated with cyanogenic glucosides using vibrational spectroscopy. Raman h...

Our study examined the response of ten plant communities across Victoria, Australia to the infestation and subsequent removal of Pittosporum undulatum, a tree native to south Eastern Australia that is increasingly viewed as an invader within and particularly beyond its native range. At sites where P. undulatum removal has occurred over a 1–14 year...

Heterotrophically grown cells of a newly isolated strain of Scenedesmus sp. retained their photosynthetic pigment content after prolonged darkness. When these cells had reached an apparent stationary phase and were subsequently exposed to light (mixotrophy), growth rapidly resumed and the biomass increased by 5.5-fold relative to photoautotrophical...

Previously, the best ways of inducing oil production by algae was to remove the nitrogen source in the medium or to provide a fixed, small amount of N and allowing cells to enter a state of N depletion. These conventional methods for achieving N starvation are time consuming and expensive; therefore an alternative method is needed. Here we show tha...

Rising sea levels are threatening agricultural production in coastal regions due to inundation and contamination of groundwater. The development of more salt-tolerant crops is essential. Cassava is an important staple, particularly among poor subsistence farmers. Its tolerance to drought and elevated temperatures make it highly suitable for meeting...

Cassava is an important dietary component for over 1 billion people, and its ability to yield under drought has led to it being promoted as an important crop for food security under climate change. Despite its known photosynthetic plasticity in response to temperature, little is known about how temperature affects plant toxicity or about interactio...

The importance of algae-derived biofuels has been highlighted by the current problems associated with fossil fuels. Considerable past research has shown that limiting nutrients such as nitrogen and phosphorus increases the cellular lipid content in microalgae. However, limiting the supply of nutrients results in decreased biomass, which in turn dec...

The internationalisation of higher education generates several issues related to quality, uniformity of subjects taught across campuses and the role of differences in English-speaking ability, which may affect student learning and skills development. This study used a self-assessment survey framework to investigate Australian (native English speaki...

Transgenic plants of Nicotiana tabacum L. homozygous for an RNAi construct designed to silence ornithine decarboxylase (ODC) had significantly lower concentrations of nicotine and nornicotine, but significantly higher concentrations of anatabine, compared with vector-only controls. Silencing of ODC also led to significantly reduced concentrations o...

Transgenic plants of Nicotiana tabacum L. homozygous for an RNAi construct designed to silence ornithine decarboxylase (ODC) had significantly lower concentrations of nicotine and nornicotine, but significantly higher concentrations of anatabine, compared with vector-only controls. Silencing of ODC also led to significantly reduced concentrations o...

Cassava (Manihot esculenta) provides calories and nutrition for more than half a billion people. It was domesticated by native Amazonian peoples through cultivation of the wild progenitor M. esculenta ssp. flabellifolia and is now grown in tropical regions worldwide. Here we provide a high-quality genome assembly for cassava with improved contiguit...

In this paper we describe how digital technologies can be used to enhance collaboration and student engagement in a large, multicampus undergraduate science unit. Four innovations developed and implemented over a period of eight years are described: use of electronic whiteboards, on-line discussion forums, social media and blogs. In showing the int...

Making material available through learning management systems is standard practice in most universities, but this is generally seen as an adjunct to the 'real' teaching, that takes place in face-to-face classes. Lecture attendance is poor, and it is becoming increasingly difficult to engage students, both in the material being taught and campus lif...

Highlights • Phosphorus starvation resulted in higher cellular lipid levels in C. reinhardtii. • Phosphorus starvation also resulted in higher respiration rates. • Photosynthetic parameters remained unaffected in the absence of phosphorus. • No difference in lipid productivity was observed in the absence of phosphorus. • P-starvation may help reduc...

Making material available through learning management systems is standard practice in most universities, but this is generally seen as an adjunct to the ‘real’ teaching, that takes place in face-to-face classes. Lecture attendance is poor, and it is becoming increasingly difficult to engage students, both in the material being taught and campus lif...

Many important food crops produce cyanogenic glucosides as natural defence compounds to protect against herbivory or pathogen attack. It has also been suggested that these nitrogen based secondary metabolites act as storage reserves of nitrogen. In sorghum three key genes, CYP79A1, CYP71E1 and UGT85B1 encode two cytochrome P450s and a glycosyltrans...

The biosynthetic pathway for the cyanogenic glucoside, dhurrin, in sorghum has previously been shown to involve the sequential production of (E) - and (Z)-p-hydroxyphenylacetaldoxime. In this study we used microsomes prepared from wild type and mutant sorghum or transiently transformed Nicotiana benthamiana to demonstrate that CYP79A1 catalyzes con...

Making material available through learning management systems is standard practice in most universities, but this is generally seen as an adjunct to the ‘real’ teaching, that takes place in face-to-face classes. Lecture attendance is poor, and it is becoming increasingly difficult to engage students, both in the material being taught and campus lif...

The high cost of production of algal biofuel raises questions about its practical implementation on an industrial scale. Increasing the oil productivity of algae and using cheap growth medium are good ways of resolving this issue. A large research effort directed into this area shows that limiting the nitrogen source in the media increases cellular...

Student writing proficiency is considered to be a hallmark of educational excellence. This study reports on an iterated writing skills development program, incorporating elements of content, form and context, for science undergraduates. The program, which was initiated in first year biology and then iterated through a second year science unit, inve...

Cyanogenic glycosides (CNglcs) are bioactive plant products derived from amino acids. Structurally, these specialized plant compounds are characterized as α-hydroxynitriles (cyanohydrins) that are stabilized by glucosylation. In recent years, improved tools within analytical chemistry have greatly increased the number of known CNglcs by enabling th...

Pittosporum undulatum was identified as an invader of forests and woodlands in southern Australia over 30 years ago (Gleadow and Ashton 1981). At the time it was predicted that its high reproductive potential, suppression of competitors, changed management practices and broad tolerance of environmental challenges could result in serious infestation...

Arbuscular mycorrhizas (AM) can increase plant acquisition of P and N. No published studies have investigated the impact of P and AM on the allocation of N to the plant defence, cyanogenic glucosides. We investigated the effects of soil P and AM on cyanogenic glucoside (dhurrin) concentration in roots and shoots of two forage sorghum lines differin...

Sorghum (Sorghum bicolor L. Moench) is a valuable forage crop in regions with low soil moisture. Sorghum may accumulate high concentrations of the cyanogenic glucoside dhurrin when drought stressed resulting in possible cyanide (HCN) intoxication of grazing animals. In addition, high concentrations of nitrate, also potentially toxic to ruminants, m...

The papers in this special issue were mainly derived from sessions at the International Botanical Congress in July 2011 in Melbourne, and at the ComBio meeting in Cairns, September 2011. They make contributions towards one of the most burning issues we face today: increasing sustainable crop production to provide sufficient high quality food to fee...

Talks in the third thread of the climate change symposium, Impacts, focused on possible impacts on sea level rises (Dr Kathleen McInnes), water resources (Dr Dasarath Jaya Jayasuriya), human health (Associate Professor Grant Blashki) and agriculture (Dr Leanne Webb) in the Victorian context. The series of articles here summarise the state of knowle...

Cassava (Manihot esculenta Crantz) is the staple food source for over 850 million people worldwide. Cassava contains cyanogenic glucosides and can be toxic to humans, causing paralysing diseases such as konzo, and even death if not properly processed. Konzo epidemics are often associated with times of drought. This may be due to a greater reliance...

Cyanogenic glucosides are common bioactive products that break down to release toxic hydrogen cyanide (HCN) when combined with specific β-glucosidases. In forage sorghum, high concentrations of the cyanogenic glucoside dhurrin lead to reduced productivity and sometimes death of grazing animals, especially in times of drought, when the dhurrin conte...

Globally, cassava is the second most important root crop after potatoes and the fifth most important crop overall in terms of human caloric intake. In addition to its growing global importance for feed, fuel, and starch, cassava has long been vital to food security in Sub-Saharan Africa. Climate change is expected to have its most severe impact on...