1,721,170 research outputs found
Impulse Lecture How specialized metabolites mediate interactions between plants and other organisms
No full textSmall molecular weight organic compounds are common across the galaxy and transcend all known biological interactions. Plants, in particular, have evolved a remarkable capacity to produce diverse sets of so-called specialized metabolites from a few simple, inorganic precursors. Already in 1977, Rhoades argued that plant specialized metabolites are likely multifunctional, i.e. that they serve multiple purposes. Multifunctionality may render the production of specialized metabolites more cost effective and may explain their abundance and tight spatiotemporal control in plants. Work over the last decades confirms that specialized metabolites often have a broad range of functions, from growth and development to defense [1]. However, our understanding of how this multifunctionality affects the interactions between plants and other organisms, including herbivores and their natural enemies is limited. In my presentation, I will explore the importance of multifunctional plant metabolites for plant-environment interactions by discussing our work on benzoxazinoids, the most abundant specialized metabolites in grasses such as wheat and maize. We find that benzoxazinoids act as direct defenses, within-plant defense signaling molecules, microbiome modulators and siderophores. At the same time, the western corn rootworm, a specialist maize pest and important agricultural pest, exploits benzoxazinoids as foraging cues, protective agents and micronutrient providers. Thus, the multifunctionality of plant specialized metabolites is mirrored in the adaptations of a specialist herbivore, resulting in a tightly interlocked metabolism. These findings have implications for our understanding of the ecology and evolution of plant specialized metabolites, and for their use in agriculture and medicine
The Inverted Phantom Giant
Full text linkIn his famous children’s book, “Jim Button and Luke the
Engine Driver”, Michael Ende describes a curious character:
A phantom giant. Clothed in rags and with a long beard, the
phantom giant appears enormous from far away, but shrinks to
normal size as one gets closer. Most people avoid the poor
creature, but the ones that dare approach it encounter a gentle,
lonely being called Mr. Tur Tur. Chemical ecology is just the
opposite of Mr. Tur Tur: A phantom dwarf. Or, in other words,
an inverted phantom giant. From a distance, chemical ecology
appears like a slightly odd, marginal section of biology and
chemistry. But, as the interested scholar approaches, it starts
growing and very quickly reaches gigantic dimensions, because
all life is explained by chemistry, and all biological
chemistry is guided by ecological principles. Herein lies the
difficulty with chemical ecology: As it is not perceived well
by biologists and chemists, few approach it to understand its
significance, and the ones that do find themselves in front of a
giant that defies their attempts to define and contain it. This is
where the Journal of Chemical Ecology comes in: It invites us
to take a closer look at an underestimated discipline and
supports us to explore it and deal with its multidimensionality
through the promotion of knowledge and methods. These
services are unique and make the journal stand out of the
crowd of scientific journals.
Writing children’s books has become difficult in the era
of information technology. And, so has the job of the
Journal of Chemical Ecology. Young scientists gather information
through accessible, dynamic websites and social
platforms. They want articles that are available through a
single mouse click, anywhere, anytime. They prefer advanced
interactive hypertext protocols over clumsy pdf
files. They care about transparency, non-profit and open
access just as much as about traditional journal properties.
In my view, reaching “the kids” is the major challenge of
the Journal over the next years.
Promoting an inverted phantom giant in the 21st century
requires a combination of high-quality information and
boosted visibility. In Michael Ende’s book, Jim and Luke
follow exactly this strategy with Mr. Tur Tur: They become
friends and offer him a job as a living lighthouse to protect
their small island. They combine a quality relationship with
high visibility, et voilà, the story ends well! I am looking
forward to seeing if the Journal of Chemical Ecology will
follow a similar path to reach the next generation of
biologists and chemists. If yes, there is a good chance that
in 40 years from now, somebody will write a laudation and
refer to another famous book by Michael Ende: “The
Neverending Story”
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Volatile uptake, transport, perception, and signaling shape a plant's nose.
Full text linkHerbivore-induced plant volatiles regulate defenses in undamaged neighboring plants. Understanding the mechanisms by which plant volatiles are taken up, perceived, and translated into canonical defense signaling pathways is an important frontier of knowledge. Volatiles can enter plants through stomata and the cuticle. They are likely perceived by membrane-associated receptors as well as intracellular receptors. The latter likely involves metabolization and transport across cell membranes by volatile transporters. Translation of volatiles into defense priming and induction typically involves mitogen-activated protein kinases (MAPKs), WRKY transcription factors, and jasmonates. We propose that the broad range of molecular processes involved in volatile signaling will likely result in substantial spatiotemporal and ontogenetic variation in plant responsiveness to volatiles, with important consequences for plant-environment interactions
Feeding Assay to Study the Effect of Phytocytokines on Direct and Indirect Defense in Maize.
No full textPhytocytokines mediate defense against pests and pathogens. Many methods have been developed to study the physiological responses triggered by phytocytokines in dicot plants. Here, we describe a detailed peptide feeding protocol to study the effect of phytocytokines on direct and indirect anti-herbivore defense in maize. This method relies on peptide uptake by the excised maize seedling or leaves via the transpiration stream. The headspace volatiles from plant samples are then analyzed by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), or by gas chromatography-mass spectrometry (GC-MS). The samples can also be further processed to evaluate phytocytokine-induced defense gene expression or phytohormone production
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Plant Defenses against Herbivory: Closing the Fitness Gap
No full textMany morphological and chemical features of plants are classified as plant defenses against herbivores. By definition, plant defenses should increase a plant's fitness (i.e., its contribution to the gene pool of the next generation) as a function of herbivory. Over the past years, substantial progress has been made in understanding and manipulating the mechanistic basis of many putative plant defense traits. However, most plant defenses are still characterized by proximate variables such as herbivore performance or plant damage rather than actual fitness. Determining fitness benefits as a function of herbivory therefore remains a major knowledge gap that must be filled to understand the ecology and evolution of plant defenses
The Role of Roots in Plant Defence
No full textRoots play an important role for plant defence and resistance against pathogens and insect herbivores: They act as environmental sensors for space, nutrients and water, they are important biosynthetic sites of plant toxins, they can store assimilates for future regrowth, and they possess themselves a potent defensive system to fend off belowground attackers. Although roots are often seen as passive tissue that only delivers services to the rest of the plant, it is becoming increasingly evident that roots actively respond to environmental conditions and are a vital part of the plant’s signaling and perception machinery. This chapter summarizes what is known about roots as constituents of plant resistance and defense mechanisms, with a particular emphasis on signaling aspects. It also discusses how the increasing knowledge about roots can be used to help protect plants from harmful pests
Molecular Interactions Between Plants and Insect Herbivores
No full textDiverse molecular processes regulate the interactions between plants and insect herbivores. Here, we review genes and proteins that are involved in plant–herbivore interactions and discuss how their discovery has structured the current standard model of plant–herbivore interactions. Plants perceive damage-associated and, possibly, herbivore-associated molecular patterns via receptors that activate early signaling components such as Ca2+, reactive oxygen species, and MAP kinases. Specific defense reprogramming proceeds via signaling networks that include phytohormones, secondary metabolites, and transcription factors. Local and systemic regulation of toxins, defense proteins, physical barriers, and tolerance traits protect plants against herbivores. Herbivores counteract plant defenses through biochemical defense deactivation, effector-mediated suppression of defense signaling, and chemically controlled behavioral changes. The molecular basis of plant–herbivore interactions is now well established for model systems. Expanding molecular approaches to unexplored dimensions of plant–insect interactions should be a future priority
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