Efficient cell reprogramming as a target for functional-marker strategies? Towards new perspectives in applied plant-nutrition research

The review aims at visualizing and strengthening approximation of current strategies in plant breeding, plant nutrition, and molecular biology. Innovations in new breeding strategies on quantitative traits are based on the development of functional DNA markers. This requires knowledge on robust physiological key reactions or parameters in view of the desired agronomic trait. To understand the significance of adaptive molecular-physiological factors for the expression of agronomic traits in quantitative terms, systems analyses have to demonstrate the phenotypic effect of differential gene activities. The logistic to advance in applied systems biology is currently being strongly discussed. In the present contribution, identification of target cells, which are important for agronomic traits, is stressed as a key for future modeling and virtual experimentation. Integration of target cells in systems analysis should allow to link top-down approaches, that start at the whole-plant level, with bottom-up approaches, that come from the molecular level. To illustrate the importance of adaptive cell reprogramming for agronomic traits, reprogramming of rhizodermic cells to trichoblasts is pointed out in its role for nutrient efficiency (NE). The nature of molecular factors, which may serve as functional markers in breeding, is discussed in view of future marker development

Unravelling wild carrot differentiation in Europe: preliminary data on a candidate gene approach

Carrot is an outcrossing species and levels of gene flow between populations, and even between wild and domesticated relatives, are expected to be high. Cases of natural hybridization and introgression of crops and wild relatives have been reported. Have these events diluted any putative habitat-adapted genotypes? In other words, can we still find a correlation between wild carrot genotypes and regional/local environment? We have chosen to start addressing this question using a member of the alternative oxidase (AOX) gene family. AOX genes seem to be linked to all kinds of abiotic and biotic stress reactions. Wild carrots were sampled in an environmental gradient across Western Europe. This gradient included sampling points with more deviating conditions, such as Sierra de Guadarrama or the central Pyrenees and the French Massif Central. Phylogenetic reconstruction on this molecular marker is to be combined with geographic, climatic, and ecological evidence. So far, the preliminary results suggest the existence of a biogeographical barrier at the Pyrenees, and higher gene diversity than initially expected. From an applied point of view, diversity of functional traits is much more relevant than species diversity. Gene transfer from wild to cultivated plants has contributed to the evolution of crop species. Providing that deterioration of genetic resources and biodiversity loss have not been drastic, gene transfer from wild plants has the potential to further contribute to a (targeted) improvement of cultivars.info:eu-repo/semantics/publishedVersio

Aox gene structure, transcript variation and expression in plants

Alternative oxidase (Aox) has been proposed as a functional marker for breeding stress tolerant plant varieties. This requires presence of polymorphic Aox allele sequences in plants that affect plant phenotype in a recognizable way. In this review, we examine the hypothesis that organization of genomic Aox sequences and gene expression patterns are highly variable in relation to the possibility that such a variation may allow development of Aox functional markers in plants. Aox is encoded by a small multigene family, typically with four to five members in higher plants. The predominant structure of genomic Aox sequences is that of four exons interrupted by three introns at well conserved positions. Evolutionary intron loss and gain has resulted in the variation of intron numbers in some Aox members that may harbor two to four introns and three to five exons in their sequence. Accumulating evidence suggests that Aox gene structure is polymorphic enough to allow development of Aox markers in many plant species. However, the functional significance of Aox structural variation has not been examined exhaustively. Aox expression patterns display variability and typically Aox genes fall into two discrete subfamilies, Aox1 and Aox2, the former being present in all plants and the latter restricted in eudicot species. Typically, although not exclusively, the Aox1-type genes are induced by many different kinds of stress, whereas Aox2-type genes are expressed in a constitutive or developmentally regulated way. Specific Aox alleles are among the first and most intensively stressinduced genes in several experimental systems involving oxidative stress. Differential response of Aox genes to stress may provide a flexible plan of plant defense where an energy-dissipating system in mitochondria is involved. Evidence to link structural variation and differential allele expression patterns is scarce. Much research is still required to understand the significance of polymorphisms within AOX gene sequences for gene regulation and its potential for breeding on important agronomic traits. Association studies and mapping approaches will be helpful to advance future perspectives for application more efficiently

Reference Genes Selection and Normalization of Oxidative Stress Responsive Genes upon Different Temperature Stress Conditions in Hypericum perforatum L

Abstract Reverse transcription-quantitative real-time PCR (RT-qPCR) is a widely used technique for gene expression analysis. The reliability of this method depends largely on the suitable selection of stable reference genes for accurate data normalization. Hypericum perforatum L. (St. John’s wort) is a field growing plant that is frequently exposed to a variety of adverse environmental stresses that can negatively affect its productivity. This widely known medicinal plant with broad pharmacological properties (anti-depressant, anti-tumor, anti-inflammatory, antiviral, antioxidant, anti-cancer, and antibacterial) has been overlooked with respect to the identification of reference genes suitable for RT-qPCR data normalization. In this study, 11 candidate reference genes were analyzed in H. perforatum plants subjected to cold and heat stresses. The expression stability of these genes was assessed using GeNorm, NormFinder and BestKeeper algorithms. The results revealed that the ranking of stability among the three algorithms showed only minor differences within each treatment. The best-ranked reference genes differed between cold- and heat-treated samples; nevertheless, TUB was the most stable gene in both experimental conditions. GSA and GAPDH were found to be reliable reference genes in cold-treated samples, while GAPDH showed low expression stability in heat-treated samples. 26SrRNA and H2A had the highest stabilities in the heat assay, whereas H2A was less stable in the cold assay. Finally, AOX1, AOX2, CAT1 and CHS genes, associated with plant stress responses and oxidative stress, were used as target genes to validate the reliability of identified reference genes

Kitchen-Sink Enlightenment: A Review of “Grace for Amateurs”

Excerpt: Here’s an honest admission: Several times while reading Lily Burana’s new book Grace for Amateurs: Field Notes on a Journey Back to Faith, I consulted the copyright page, confirming again that Grace for Amateurs was really published by Thomas Nelson, the notoriously evangelical (and, in my mind, notoriously traditional) press. After all, it wasn’t that long ago that Thomas Nelson asked another writer to remove the word “vagina” from her book, well aware that Christian readers would balk at language so closely associated with women and S-E-X. Would this same publisher be willing to support a memoir as edgy and progressive as Burana’s

Isolation of alternative oxidase (AOX) genes of Olea europaea L.

Alternative oxidase (AOX) is recently suggested to be a potential candidate as functional marker for efficient cell reprogramming under stress (Arnholdt-Schmitt et al., 2006a). The presented work is part of a Marie Curie Chair project, that was established to investigate the potential role of the multigene AOX to assist breeding on efficient rooting of olive shoot cuttings (Arnholdt-Schmitt et al. 2006b). Plant mito-chondrial AOX is a small nuclear-encoded multigene family consisting of the two subfamilies AOX1 and AOX2. The intron-exon structure of AOX has been well characterized in several species, revealing a large degree of conservation. Here we report for the first time about the isolation of AOX multigene se-quences of olive (Olea europaea L.). The genes were isolated from a portuguese clone of the landrace ‘Galega vulgar’

Temperature responses of substrate carbon conversion efficiencies and growth rates of plant tissues

Growth rates of plant tissues depend on both the respiration rate and the efficiency with which carbon is incorporated into new structural biomass. Calorespirometric measurement of respiratory heat and CO2 rates, from which both efficiency and growth rate can be calculated, is a well established method for determining the effects of rapid temperature changes on the respiratory and growth properties of plant tissues. The effect of the alternative oxidase/cytochrome oxidase activity ratio on efficiency is calculated from first principles. Data on the temperature dependence of the substrate carbon conversion efficiency are tabulated. These data show that ε is maximum and approximately constant through the optimum growth temperature range and decreases rapidly as temperatures approach temperature limits to growth. The width of the maximum and the slopes of decreasing ε at high and low temperatures vary greatly with species, cultivars and accessions

AOX a functional marker for efficient cell reprogramming under stress?

Functional markers for stress tolerance can be used in plant breeding to identify genotypes with high yield stabilities under various conditions. Thus, a good marker should show a strong correlation with favourable adaptive plant behaviour. The efficient reprogramming of target cells for yield determination is currently considered to be the most important step towards defining abiotic stress tolerance. In this Opinion article, we propose a role for the alternative oxidase (AOX) gene as a marker for genetic variation in cell reprogramming and yield stability. Evidence to support this idea comes from the metabolic role of alternative respiration under stress, the link between AOX activity and differential growth, and the single nucleotide polymorphism recently observed in AOX genes. We propose an innovative, interdisciplinary and global research strategy for future experimentation on AOX genes that could have an application in plant breeding

Educação ambiental na educação infantil: as vivências com a natureza no pátio da escola

A educação vem revendo suas concepções teórico-práticas a fim de manter-se atualizada diante das transformações sociais. Especificamente, no campo da Educação Ambiental busca-se acompanhar esses processos de modo a ampliar seu espaço e tornar suas práticas mais contextualizadas nas realidades das escolas. Assim, a formação dos professores precisa acompanhar estas mudanças para qualificar os processos de ensino e de aprendizagem e manter a atualização das práticas. As crianças vêm convivendo cada vez mais com uma realidade urbana e tecnológica, distanciando-se, muitas vezes, das interações com a natureza. Neste sentido, a Educação Ambiental vem a contribuir para a aproximação do ser humano com a natureza retomando esse contato essencial. Na etapa de ensino da Educação Infantil as crianças passam muitas horas do dia na escola, explorando os pátios, espaços externos e ambientes naturais no próprio ambiente escolar, muitas vezes mais do que com as próprias famílias. Sendo assim, esta pesquisa propõe um programa de formação continuada para professores de Educação Infantil, na área da Educação Ambiental como meio para motivação e orientação da exploração dos pátios das escolas através do método do Aprendizado Sequencial e das vivências com a natureza. A abordagem da pesquisa é qualitativa. Exploram-se possibilidades de intervenções participantes. Problematiza-se de que forma a Educação Ambiental na Educação Infantil pode explorar os pátios das escolas constituindo-os em ambientes de aprendizagem e em que medida a formação continuada de professores de Educação Infantil nas vivências com a natureza propostas pelo método da Aprendizagem Sequencial possibilita isso. Assim, tem-se como objetivo investigar a potência das vivências com a natureza enquanto método de Educação Ambiental na Educação Infantil explorando os pátios das escolas como ambientes de aprendizagem. Foram organizadas três categorias para análise comparativa as quais contemplaram as potências da Educação Ambiental na Educação Infantil a partir dos seguintes aspectos: as vivências com a natureza através do Método do Aprendizado Sequencial; a formação continuada dos professores referente ao método em questão para a exploração do pátio das escolas e o pátio das escolas como ambiente de aprendizagem. Como resultados evidenciaram-se a potência do método do Aprendizado Sequencial e das vivências com a natureza em relação às práticas na e com a Educação Infantil, bem como a importância de formação continuada para os professores sentirem-se instigados e motivados a buscar conhecimentos para desacomodar suas propostas e as possibilidades diversificadas 7 de exploração dos pátios enquanto ambientes de aprendizagem em Educação Ambiental na Educação Infantil.Education has been revising its theoretical-practical conceptions in order to keep abreast of social transformations. The field of Environmental Education specifically, seeks to follow these new processes in order to expand their space and make their practices more contextualized in the realities of schools. Thus, teacher training needs to follow these changes to qualify the teaching, learning processes and keep updating practices. Children are increasingly living with an urban and technological creality, often distancing themselves from interactions with nature. This way, the Environmental Education comes to contribute to the approximation of the human being with nature resuming this essential contact. At the early childhood education stage, children spend many hours a day at school, exploring courtyards, outdoor spaces and natural environments in their own school environment, often more than with their own families. Thus, this research proposes a continuing education program for teachers of Early Childhood Education in the area of Environmental Education as a way to motivate and guide the exploration of school yards through the method of Sequential Learning and experiences with nature. The research approach is qualitative. Possible interventions are explored. It is asked how Environmental Education in Early Childhood Education can explore the schools' courts by establishing them in learning environments and, what extent the continuing education of Early Childhood teachers in the experiences with nature proposed by the method of Sequential Learning makes it possible. Thus, the research‟s objective is to investigate the potency of experiences with nature as a method of Environmental Education in Early Childhood Education exploring the courtyards of schools as learning environments. Three categories for comparative analysis were organized, which included the powers of Environmental Education in Early Childhood Education from the following aspects: the experiences with nature through the Sequential Learning Method; the continuous training of teachers regarding the method in question for the operation of the schoolyard and the schoolyard as a learning environment. As results, the framework of the Sequential Learning method and the experiments with nature and the practice with Early Childhood Education, as well as the importance of continuous formation for the teachers to feel instigated and motivated to seek knowledge to disagree their proposals and the diversified possibilities of exploring the courtyards as learning environments in Environmental Education in Early Childhood Education