Growth curve analysis of sedentary plant parasitic nematodes on different hosts and at different population densities is used to assess plant suitability including their resistance and tolerance. The estimated parameters of host suitability can be used in pest management programs for economic important species such as potato cyst nematodes.
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Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to identify bacterial determinants and underlying mechanisms involved in plant growth promotion and ISR by Pf.SS101. Based on targeted analyses, no evidence was found for volatiles, lipopeptides and siderophores in plant growth promotion by Pf.SS101. Untargeted, genome‐wide analyses of 7488 random transposon mutants of Pf.SS101 led to the identification of 21 mutants defective in both plant growth promotion and ISR. Many of these mutants, however, were auxotrophic and impaired in root colonization. Genetic analysis of three mutants followed by site‐directed mutagenesis, genetic complementation and plant bioassays revealed the involvement of the phosphogluconate dehydratase gene edd, the response regulator gene colR and the adenylsulfate reductase gene cysH in both plant growth promotion and ISR. Subsequent comparative plant transcriptomics analyses strongly suggest that modulation of sulfur assimilation, auxin biosynthesis and transport, steroid biosynthesis and carbohydrate metabolism in Arabidopsis are key mechanisms linked to growth promotion and ISR by Pf.SS101.
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Measuring plant health and status is key for growers in the Dutch greenhouse horticulture industry to create optimal conditions for plant growth and predictability and optimization of yield with minimal energy cost. Within the ‘Gewasgroei Goed Gemeten’ project led by The Hague University of Applied Sciences (project leader dr. John Bolte), plant data plays a key role. The consortium of researchers and entrepreneurs aims to pave the way towards large-scale application of sensor technology to record plant growth. Such a large-scale application asks for accurate, but low-cost sensors to be developed. Results of this project’s research and development, together with suppliers, growers and breeders, will advance the technology for Dutch horticulture and abroad, where there is a growing demand for Dutch knowledge and expertise.
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Control of plant growth is an important aspect of crop productivity and yield in agriculture. Overexpression of the At CHR12/ 23 genes in Arabidopsis thaliana reduced growth habit without other morphological changes. These two genes encode Snf2 chromatin remodelling ATPases. Here, we translate this approach to the horticultural crop tomato ( Solanum lycopersicum). We identified and cloned the single tomato ortholog of the two Arabidopsis Snf2 genes, designated Sl CHR1. Transgenic tomato plants (cv. Micro-Tom) that constitutively overexpress the coding sequence of Sl CHR1 show reduced growth in all developmental stages of tomato. This confirms that Sl CHR1 combines the functions of both Arabidopsis genes in tomato. Compared to the wild type, the transgenic seedlings of tomato have significantly shorter roots, hypocotyls and reduced cotyledon size. Transgenic plants have a much more compact growth habit with markedly reduced plant height, severely compacted reproductive structures with smaller flowers and smaller fruits. The results indicate that either GMO-based or non- GMO-based approaches to modulate the expression of chromatin remodelling ATPase genes could develop into methods to control plant growth, for example to replace the use of chemical growth retardants. This approach is likely to be applicable and attractive for any crop for which growth habit reduction has added value.
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The increased cultivation of highly productive C4 crop plants may contribute to a second green revolution in agriculture. However, the regulation of mineral nutrition is rather poorly understood in C4 plants. To understand the impact of C4 photosynthesis on the regulation of sulfate uptake by the root and sulfate assimilation into cysteine at the whole plant level, seedlings of the monocot C4 plant maize (Zea mays) were exposed to a non-toxic level of 1.0 µl l−1 atmospheric H2S at sulfate-sufficient and sulfate-deprived conditions. Sulfate deprivation not only affected growth and the levels of sulfur- and nitrogen-containing compounds, but it also enhanced the expression and activity of the sulfate transporters in the root and the expression and activity of APS reductase (APR) in the root and shoot. H2S exposure alleviated the establishment of sulfur deprivation symptoms and seedlings switched, at least partly, from sulfate to H2S as sulfur source. Moreover, H2S exposure resulted in a downregulation of the expression and activity of APR in both shoot and root, though it hardly affected that of the sulfate transporters in the root. These results indicate that maize seedlings respond similarly to sulfate deprivation and atmospheric H2S exposure as C3 monocots, implying that C4 photosynthesis in maize is not associated with a distinct whole plant regulation of sulfate uptake and assimilation into cysteine.
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The protein transition from animal towards plant proteins, is driven by the growth of the world’s population combined with a rising standard of living. Over the last five years, this has already resulted in a 7-fold increase in product launches with a plant-based claim or notification. This manuscript gives an overview of current, emerging and future protein sources and their use to replace protein in dairy and meat products as well as egg proteins. Currently, a major focus is on the development of products that mimic the original product the most, for example the best meat alternative. However, the question arises if this is enough to change the overall balance between animal and plant proteins? The outlook discusses the demand for a better understanding of consumer needs and preferences.
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Due to a number of factors outlined in this article, the issue of population growth is excluded from the sustainability discussion. In this article, we explore some of the ethical presumptions that underlie the issues linking population growth and sustainability. Critics argue that action to address population creates social and economic segregation, and portray overpopulation concerns as being “anti-poor,” “anti-developing country,” or even “antihuman.” Yet, de-linking demographic factors from sustainability concerns ignores significant global realities and trends, such as the ecological limits of the Earth, the welfare and long-term livelihood of the most vulnerable groups, future prospects of humanity, as well as the ecosystems that support society. https://doi.org/10.1080/10042857.2016.1149296 LinkedIn: https://www.linkedin.com/in/helenkopnina/
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There is consensus that plant species richness enhances plant productivity within natural grasslands, but the underlying drivers remain debated. Recently, differential accumulation of soil‐borne fungal pathogens across the plant diversity gradient has been proposed as a cause of this pattern. However, the below‐ground environment has generally been treated as a ‘black box’ in biodiversity experiments, leaving these fungi unidentified. Using next generation sequencing and pathogenicity assays, we analysed the community composition of root‐associated fungi from a biodiversity experiment to examine if evidence exists for host specificity and negative density dependence in the interplay between soil‐borne fungi, plant diversity and productivity. Plant species were colonised by distinct (pathogenic) fungal communities and isolated fungal species showed negative, species‐specific effects on plant growth. Moreover, 57% of the pathogenic fungal operational taxonomic units (OTUs) recorded in plant monocultures were not detected in eight plant species plots, suggesting a loss of pathogenic OTUs with plant diversity. Our work provides strong evidence for host specificity and negative density‐dependent effects of root‐associated fungi on plant species in grasslands. Our work substantiates the hypothesis that fungal root pathogens are an important driver of biodiversity‐ecosystem functioning relationships.
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The Dutch greenhouse horticultural industry is characterized by world leadership in high-tech innovation. The dynamics of this playing field are innovation in production systems and automation, reduction in energy consumption and sharing limited space. However, international competitive advantage of the industry is under pressure and sustainable growth of individual enterprises is no longer a certainty. The sector's ambition is to innovate better and grow faster than the competition in the rest of the world. Realizing this ambition requires strengthening the knowledge base, stimulating entrepreneurship, innovation (not just technological, but especially business process innovation). It also requires educating and professionalizing people. However, knowledge transfer in this industry is often fragmented and innovation through collaboration takes up a mere 25-30% of the opportunities. The greenhouse horticulture sector is generally characterized by small scale, often family run businesses. Growers often depend on the Dutch auction system for their revenues and suppliers operate mainly independently. Horizontal and vertical collaboration throughout the value chain is limited. This paper focuses on the question: how can the grower and the supplier in the greenhouse horticulture chain gain competitive advantage through radical product and process innovation. The challenge lies in time- to-market, in customer relationship, in developing new product/market combinations and in innovative entrepreneurship. In this paper an innovation and entrepreneurial educational and research programme is introduced. The programme aims at strengthening multidisciplinary collaboration between enterprise, education and research. Using best practice examples, the paper illustrates how companies can realize growth and improve innovative capabilities of the organization as well as the individual by linking economic and social sustainability. The paper continues to show how participants of the programme develop competencies by means of going through a learning cycle of single-loop, double-loop and triple loop learning: reduction of mistakes, change towards new concepts and improvement of the ability to learn. Furthermore, the paper discusses our four-year programme, whose objectives are trying to eliminate interventions that stimulate the innovative capabilities of SME's in this sector and develop instruments that are beneficial to organizations and individual entrepreneurs and help them make the step from vision to action, and from incremental to radical innovation. Finally, the paper illustrates the importance of combining enterprise, education and research in networks with a regional, national and international scope, with examples from the greenhouse horticulture sector. These networks generate economic regional and national growth and international competitiveness by acting as business accelerators.
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Young widowhood, conceptualized as the loss of one’s spouse before the age of 50, is a profoundly painful and distressing loss (Den Elzen, 2017, 2018). The literature on young widowhood shows the death of a partner generally causes a fragmentation of the self, as it violates expectations of the normal life cycle, namely growing old together (Haase and Johnston, 2012; Levinson, 1997). Premature loss of one’s spouse tends to be experienced by the surviving partner as distressing or traumatizing, such as having witnessed their suffering in illness or through accident (Den Elzen, 2018) or in struggling with unfinished business (Holland et al, 2020). Whilst post-traumatic stress is well-known and has been widely researched across various disciplines, the concept of post-traumatic growth is much newer and by contrast has received less attention. PTG was introduced as a scholarly concept by Tedeschi and Calhoun in the mid-1990s and is defined as a positive psychological change as a result of the struggle with highly challenging life events (2004). Calhoun and Tedeschi’s notion of PTG has been backed by a recent systematic review. In the first meta-analysis of moderate-to-high PTG, Wu et al. found that of the 10,181 subjects, about 50% experienced PTG (2019). They also reported that women, young people and victims of trauma experienced higher levels of PTG than men, the elderly and those who experienced indirect trauma. PTG has attracted some controversy, with some researchers questioning its scientific validity (Jayawickreme and Blackie, 2014). Others caution against the minimization of people’s suffering. Hayward is a trauma counsellor who advises approaching PTG carefully, highlighting that if it is introduced with clients too early it can "often be construed as minimizing someone's pain and suffering and minimizing the impact of the loss" (cited in Collier, 2016, n.p.). In addressing the critique of PTG, Calhoun and Tedeschi (2006) emphasize that the focus on investigating positive psychological change following trauma does not deny the common and well-documented negative psychological responses and distress following severe life stresses: “Negative events tend to produce, for most persons, consequences that are negative” (p.4). They argue however, and their research supports this finding, that for many people distressful events can foster positive psychological changes. We view PTG as a possibility following (profound) loss, and emphasize that PTG may continue to co-exist with painful and/or unresolved emotions regarding the loss itself. We conceptualize PTG as a continuum and not as an either/or binary with grief. Further, we wish to highlight that PTG is a highly individual process that depends on many factors, and we are not suggesting that the absence of PTG is to be seen as a failure. This chapter intends to contribute to the study of PTG through a person-centered approach. The most used method to assess PTG is the 21-item posttraumatic growth inventory developed by Calhoun and Tedeschi in 1996 (Jayawickreme & Blackie, 2014). Self-reported posttraumatic growth has been the foundation of PTG research, which has aimed to identify to what extent PTG evokes improved psychological and physical health. In discussing our own creative narrative processes of PTG, our practice-led-research lens aims to contribute to research on how PTG might be fostered. We propose a Writing-for-wellbeing approach in this context and explore what it offered us both as writers and widows and what it might offer the field of Writing-for-wellbeing and by extension clinical and scholarly practice.
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