Phenotypic Diversity and Altered Environmental Plasticity in <i>Arabidopsis thaliana</i> with Reduced Hsp90 Levels

The molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to preventing the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by the necessity of reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, increases morphological diversity, and decreases the developmental stability of repeated characters. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine the role of HSP90 as a central interface between organism, development, and environment.</p

Phenotypic Diversity and Altered Environmental Plasticity in Arabidopsis thaliana with Reduced Hsp90 Levels

The molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to preventing the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by the necessity of reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, increases morphological diversity, and decreases the developmental stability of repeated characters. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine the role of HSP90 as a central interface between organism, development, and environment

Taxonomy based on science is necessary for global conservation

Peer reviewe

Resistência parasitária em helmintos de eqüídeos e propostas de manejo Parasite resistance on helminths of equids and management proposal’s

Os eqüinos apresentam uma grande variedade de parasitas em sua fauna helmíntica, e algumas espécies/gêneros são de relevada importância, como: Parascaris equorum, Anoplocephala perfoliata, Oxyuris equi, Cyathostomum spp. e Strongylus spp. O controle destas infecções depende principalmente da utilização de produtos antiparasitários de forma supressiva ou estratégica e, em menor escala, de forma curativa. O tratamento supressivo é o fator mais importante na promoção da seleção de organismos resistentes, prejudicando a sustentabilidade de qualquer programa sanitário. As formas de detecção da resistência parasitária são onerosas e as mais comuns expressam resultados imprecisos. Entretanto, estas técnicas servem para monitorar a evolução e determinar os organismos envolvidos. A combinação de drogas é uma ferramenta que deve ser utilizada com muita cautela, pois esta alternativa não garante uma redução significativa de organismos resistentes aos compostos envolvidos. O objetivo deste artigo é apresentar formas de planejamento que auxiliem a melhorar a condição sanitária, o bem-estar dos animais e preserve o efeito tóxico dos produtos antiparasitários.<br>Equines harbour a variety of parasitic organisms on their helminth fauna and there are a few species/genus of interest, such as: Parascaris equorum, Anoplocephala perfoliata, Oxyuris equi, Cyathostomum spp. and Strongylus spp. The control of these infections relies mostly on the suppressive or strategic usage of antiparasitic compounds, and to a less extent on curative/salvage treatments. Suppressive treatment is the most important factor regarding the selection of resistant organisms, causing the impairment of sanitary programs. Detection methods of parasite resistance are expensive and the most common ones express variable results. Although, these techniques allow monitoring the evolution and the determination of which organisms are involved. Drug combination is a toll that should be used with caution, because it may not reduce the presence of resistant organisms to the compounds involved. The objective of this article is to demonstrate control alternatives that would contribute to sanitary management, to improve animal welfare and to preserve the toxic effect of the antiparasitic products

Taxonomy based on science is necessary for global conservation

International audienc