PROJECTS
Physiological and functional phenotyping of aquaporins in the regulatory mechanism of drought tolerance of tomato
Tomato (Solanum lycopersicum) is both an important food crop and a model plant species. However, drought causes serious losses in the productivity of tomato plants. Aquaporins are known as the main channels for the transport of water and involved in drought recovery. Unfortunately, and despite their great importance, the individual and integrated functions of aquaporins involved in tomato drought response remain unclear. Our aim is to unravel and to understand the functions of aquaporins in the regulatory mechanism of drought tolerance of tomato. CRISPR-Cas9 system will be used to knockout the 47 aquaporins genes of tomato one by one. Wild and transgenic plants will be comparatively, continuously and simultaneously submitted to five different treatments (Control, Drought, Recover-1, Recover-2, and Recover-3) in two different experiments (greenhouse and field). Quantitative physiological traits such as biomass, relative water content, Water-Use-Efficiency, stomatal conductance (gs) and drought start point will be recorded. In order to assess the specificity of responses to drought, relative expressions of the 47 AQPs genes in different tissues (root, stem, leaf, flower, and fruit), and in different treatments, will be measured by using Quantitative Real-Time PCR (qRT-PCR). Data will be analyzed by R software, or SAS, or SPARK Analytics.
Effet du stress salin sur l’accès à l’eau du système racinaire du riz : modélisation structurale et fonctionnelle
La salinité est l’une des contraintes majeures qui affecte le rendement agricole. Les modèles racinaires constituent les outils essentiels pour identifier les traits racinaires clés permettant à la plante de résister à la salinité. Cette étude a pour objectif d’utiliser les modèles racinaires pour comprendre les implications fonctionnelles, notamment en termes de capacité de prise d’eau, de barrière contre les ions toxiques, et des modifications de l’architecture racinaire suite à un stress salin chez le riz.
Oryza glaberrima response strategies to salinity : distinction between osmotic and ionic components
Salinity is an important environmental constraint which strongly reduces crop yield in several areas in the world. Rice (Oryza sativa) is considered as a salt-sensitive species and improvement of salt resistance is a major goal for plant breeders. Some species in the Oryza genus may constitute an interesting source of gene for rice improvement. Comparatively to the classical Asian rice species (Oryza sativa), the African rice Oryza glaberrima is poorly described for its response to salt stress. Our aims were 1-) to identify salt-tolerant varieties of O. glaberrima, 2-) to discriminate between the osmotic and the ionic components of salt stress and 3) to precise the impact of individual ions on salt deleterious impact. Plants were exposed to stress in nutrient solution or in soil culture. Then, a set of parameters related to photosynthesis, mineral nutrition, plant water status, yield and antioxidative properties were recorded. Our results showed that one accession such as TOG5307 was able to maintain a higher net photosynthesis under salt conditions and exhibited a higher level of tolerance to accumulated Na+ ions and a higher capacity for osmotic adjustment comparatively to the salt-sensitive cultivar TOG5949. TOG5307 was less affected by salinity than TOG5949 for yield-related parameters. Na+ ions appeared more toxic than Cl–, although an additive effect was recorded when both ions were simultaneously present as NaCl. The use of non-penetrating osmotic agent PEG demonstrated that osmotic and ionic component of salt stress acted in an additive way in the salt-sensitive cultivar but not in the salt-resistant one where an antagonist action was recorded for several parameters. Data were analysed in relation to expression of genes coding for ions transporters.