Impacts of Plant Growth-Promoting Rhizobacteria-based Biostimulants on Wheat Growth under Greenhouse and Field Conditions

Plant Growth-Promoting Rhizobacteria (PGPR) are one of the main biostimulant classes due to their capacity of stimulating root growth and enhancing soil mineral availability, hence increasing nutrient use efficiency in crops. The aim of this study is to screen commercially PGPR-containing products to enhance wheat growth and yield in combination with an optimized nitrogen (N) fertilizer application scheme. This could lead to a significant reduction of N fertilizer application without affecting the subsequent grain yields. The screened products collection includes (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 complemented with two strains of phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) B. subtilis, and (5) B. amyloliquefaciens b. These biostimulants were screened under greenhouse and field conditions in 2014 by using spring and winter wheat varieties respectively. There was a significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1. Under field conditions, the interaction between PGPR inoculation and N fertilizer application was assessed. The grain yield was negatively impacted by low N fertilizer applications. Under such conditions, the inoculation of the wheat rhizosphere with Bacillus subtilis increased the grain yield by 15% relative to the water control. However, in the field trial, the variability between plot replicates was high and lead to non-significant results. Based on those results, modified screening strategies for PGPR selection were set up for the 2015 trials to reduce field variability and possibly achieve higher yield increases

Projet Termitofuel: les termites et leurs symbiontes pour mieux valoriser la biomasse ligno-cellulosique

L’exploitation actuelle de la biomasse ligno-cellulosique, extrêmement abondante sur Terre, est liée à la production de déchets relativement peu valorisables. C’est pourquoi le projet TERMITOFUEL étudie la digestion du bois chez les termites, grâce à une approche pluridisciplinaire, en vue d’améliorer la production de bioéthanol de seconde génération. Au sein de l’Unité d’Entomologie Fonctionnelle et Evolutive, l’approche protéomique est employée afin d’identifier les micro-organismes présents dans le tube digestif des termites et caractériser les activités enzymatiques

Fungi Unearthed: Transcripts Encoding Lignocellulolytic and Chitinolytic Enzymes in Forest Soil

BACKGROUND: Fungi are the main organisms responsible for the degradation of biopolymers such as lignin, cellulose, hemicellulose, and chitin in forest ecosystems. Soil surveys largely target fungal diversity, paying less attention to fungal activity. METHODOLOGY/PRINCIPAL FINDINGS: Here we have focused on the organic horizon of a hardwood forest dominated by sugar maple that spreads widely across Eastern North America. The sampling site included three plots receiving normal atmospheric nitrogen deposition and three that received an extra 3 g nitrogen m(2) y(1) in form of sodium nitrate pellets since 1994, which led to increased accumulation of organic matter in the soil. Our aim was to assess, in samples taken from all six plots, transcript-level expression of fungal genes encoding lignocellulolytic and chitinolytic enzymes. For this we collected RNA from the forest soil, reverse-transcribed it, and amplified cDNAs of interest, using both published primer pairs as well as 23 newly developed ones. We thus detected transcript-level expression of 234 genes putatively encoding 26 different groups of fungal enzymes, notably major ligninolytic and diverse aromatic-oxidizing enzymes, various cellulose- and hemicellulose-degrading glycoside hydrolases and carbohydrate esterases, enzymes involved in chitin breakdown, N-acetylglucosamine metabolism, and cell wall degradation. Among the genes identified, 125 are homologous to known ascomycete genes and 105 to basidiomycete genes. Transcripts corresponding to all 26 enzyme groups were detected in both control and nitrogen-supplemented plots. CONCLUSIONS/SIGNIFICANCE: Many of these enzyme groups are known to be important in soil turnover processes, but the contribution of some is probably underestimated. Our data highlight the importance of ascomycetes, as well as basidiomycetes, in important biogeochemical cycles. In the nitrogen-supplemented plots, we have detected no transcript-level gap likely to explain the observed increased carbon storage, which is more likely due to community changes and perhaps transcriptional and/or post-transcriptional down-regulation of relevant genes

Etude moléculaire des mécanismes de régulation de l'expression du gène PUT4 codant pour la perméase spécifique de la proline de Saccharomyces cerevisiae. Etude de la structure et du rôle du gène NPR1 impliqué dans la régulation d'activité de la perméase PUT4

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Functional screening of a winter and a spring genomic DNA libraries obtained from soils in a winter wheat crop

Soils are very rich environments where the diversity of microorganisms is very high. These microorganisms play important role in the degradation of organic matter with enzymes able to degrade it. The aim of this work is to discover by functional screening new enzymatic activities of microorganisms from soils collected in winter and spring in a winter wheat crop. The genomic DNA was extracted from both soils to construct two libraries in Escherichia coli. These libraries were then screened for several enzymes such as lipase, beta-glucosidase, cellulase, α-amylase,… At this time, 2 beta-glucosidases and 3 lipases have already been found in the winter library and 3 beta-glucosidases and 1 lipase in the spring library. Sequence analyses with the BLASTX program revealed that two beta-glucosidases have less than 65% of sequence identity with known beta-glucosidases, one have 64% of identity with a known beta-galactosidase and one have 59% of identity with a glycoside hydrolase. The fifth seems to be a phosphorylase kinase (54% identity) which have a glucoamylase domain responsible for the activity. This ORF is interrupted by a transposase. Three of the four lipases have less than 60% of sequence identity with known lipases/esterases. The fourth show 55% of identity with a known beta-lactamase

At Least Two Regions Of The Oncoprotein Tre2 Are Involved In Its Lack Of Gap Activity

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