Harvesting Plant and Microbial Biodiversity for Sustainably Enhanced Food Security

According to the United Nations, the World population will reach 9 billion by 2050, with the majority of this growth occurring in developing countries. More than half of global population growth is expected to occur in Africa. On the other hand, one in nine of the World’s population suffers from chronic hunger, the vast majority of which live in developing countries (FAO et al., 2015). We therefore need to find new and sustainable solutions to feed this increasing population and alleviate the predicted negative impact of global changes on crop production. This e-Book summarize current research to improve food security and livelihoods in rural communities, reduce vulnerability, increase resilience, and mitigate land degradation in developing countries..

Auxin fluxes in the root apex co-regulate gravitropism and lateral root initiation

International audienceRoot architecture plays an important role in water and nutrient acquisition and in the ability of the plant to adapt to the soil. Lateral root development is the main determinant of the shape of the root system and is controlled by external factors such as nutrient concentration. Here it is shown that lateral root initiation and root gravitropism, two processes that are regulated by auxin, are co-regulated in Arabidopsis. A mathematical model was generated that can predict the effects of gravistimulations on lateral root initiation density and suggests that lateral root initiation is controlled by an inhibitory fields mechanism. Moreover, gene transactivation experiments suggest a mechanism involving a single auxin transport route for both responses. Finally, co-regulation may offer a selective advantage by optimizing soil exploration as supported by a simple quantitative analysis

Modeling auxin fluxes and Arabidopsis root ramification at different scales

International audienceno abstrac

Symbiotic Performance of Diverse Frankia Strains on Salt-Stressed Casuarina glauca and Casuarina equisetifolia Plants

Symbiotic nitrogen-fixing associations between Casuarina trees and the actinobacteria Frankia are widely used in agroforestry in particular for salinized land reclamation. The aim of this study was to analyze the effects of salinity on the establishment of the actinorhizal symbiosis between C. glauca and two contrasting Frankia strains (salt sensitive; CcI3 vs. salt tolerant; CeD) and the role of these isolates in the salt tolerance of C. glauca and C. equisetifolia plants. We show that the number of root nodules decreased with increasing salinity levels in both plants inoculated with CcI3 and CeD. Nodule formation did not occur in seedlings inoculated with CcI3 and CeD, at NaCl concentrations above 100 and 200 mM, respectively. Salinity also affected the early deformation of plant root hairs and reduced their number and size. In addition, expression of symbiotic marker Cg12 gene, which codes for a subtilase, was reduced at 50 mM NaCl. These data suggest that the reduction of nodulation in C. glauca under salt stress is in part due to inhibition of early mechanisms of infection. We also show that prior inoculation of C. glauca and C. equisetifolia with Frankia strains CcI3 and CeD significantly improved plant height, dry biomass, chlorophyll and proline contents at all levels of salinity tested, depending on the Casuarina-Frankia association. There was no correlation between in vitro salt tolerance of Frankia strains and efficiency in planta under salt-stressed conditions. Our results strongly indicate that increased N nutrition, photosynthesis potential and proline accumulation are important factors responsible for salt tolerance of nodulated C. glauca and C. equisetifolia

The role of hydraulics FSPMs in the context of root breeding : a case study on Pearl Millet

Developing a sustainable agricultural model is one of the great challenges of the coming years. The agricultural practices inherited from the Green Revolution of the 1960s show their limits today, and new paradigms need to be explored in the context of counter rising issues such as the multiplication of climate-change related drought episodes. Two such new paradigms are the use of functional-structural plant models to complement and rationalize breeding approaches and a renewed focus on root systems as untapped sources of plant improvement. Since the late 1980s, numerous functional and structural models of root systems were developed and used to investigate the properties of root systems in soil or lab-conditions. In this talk, we present a review on the use of multiscale functional-structural hydraulic root models in the context of drought tolerance breeding. We discuss how root models predictions can be linked to breeding studies to improve plant resistance to drought and how they can be validated to demonstrate models reliability and use. To illustrate this topic, we present a new structural model of pearl millet root system growth dynamics, combining stochastic and data-driven modules. The model is capable of simulating the development of observed root phenotypic variability of two millet genotypes chosen for their contrasted root traits. Model description, principle, assumptions, formalism and simulations will be presented during the talk

Actinorhizal nitrogen fixing nodules: infection process, molecular biology and genomics

Actinorhizal hosts are non-leguminous perennial plants belonging to 8 angiosperm families. They are capable of forming root nodules as a result of infection by a nitrogen-fixing actinomycete called Frankia. Actinorhizal nodules consist of multiple lobes, each of which represents a modified lateral root with infected cells in the expanded cortex. This article summarizes the most recent knowledge about this original symbiotic process. The infection process is described both at cytological and molecular levels. The use of transgenic Casuarinaceae for studying in actinorhizal nodules the regulation of several symbiotic promoters from legumes is also discussed. With progress in plant genome sequencing, comparative genomics in legumes and actinorhizal plants should contribute to the understanding of the evolutionary history of nitrogen-fixing symbioses. Key words : Nitrogen-fixation, actinorhizal nodules, Frankia, Casuarina, symbiotic gene. African Journal of Biotechnology Vol. 2 (12), pp. 528-538, December 200

Construcción del camino de impacto

El camino de impacto proporciona el marco para analizar el estudio. Sirve de hilo conductor para llevar a cabo el análisis y presentar los resultados en forma de informe, que se organiza siguiendo la estructura del camino de impacto. El camino de impacto incluye los datos de contexto que influyen en su desarrollo y consta de cinco fases:la contribución de los actores, que identifica las investigaciones objeto del estudio de caso, los actores implicados y sus respectivas contribuciones;los pr..

Introducción

Describir y comprender los mecanismos por los que la investigación produce resultados y efectos –e identificarlos– es un principio cada vez más extendido. Este se integra plenamente en la estrategia de colaboración equitativa del IRD con los países en desarrollo y su implicación en la ciencia de la sostenibilidad. El IRD decidió emprender este camino a finales de 2016 lanzando un proyecto piloto sobre el impacto social de las investigaciones que lleva a cabo junto con los países en desarroll..

Project Scoping

At the end of 2016, the presiding directors of IRD tasked the Mission for research evaluation and programming (MEPR) with a research project seeking to identify and describe the impact of the institute's work in the global South.ObjectivesThe objectives of this project were three-fold:to meet the expectations of IRD's supervisory authorities and of authorities in the global South countries where the institute works regarding the impact of the research conducted;improve knowledge of the actor..

La méthode par études de cas ex post

La méthode d’analyse des impacts par études de cas ex post est fondée sur l’hypothèse que les effets de la recherche sur la société sont le fruit d’interactions complexes entre une pluralité d’acteurs, scientifiques ou non, qui produisent les connaissances, les font circuler, les adaptent, les transforment et les utilisent. De telle sorte que les impacts de la recherche apparaissent comme la résultante de ce réseau d’acteurs pris dans son ensemble. Dans ce contexte, il est difficile d’attrib..