Webinaire Interne
Jeudi 15 avril 2021 à 14h00 – Séminaires des doctorants

https://inrae-fr.zoom.us/j/6465012217  –  ID de réunion : 646 501 2217

 Luciana Wilhelm (LEPSE-Equipe ETAP)

Characterization of the drought behaviour of new grapevine varieties resistant to fungal diseases in a semi-arid Mediterranean

Southern France viticulture faces the double challenge of reducing the use of chemical control against fungal diseases and finding solutions to climate change effects. The use of vine varieties that are resistant to downy and powdery mildew is a promising strategy to decrease the use of fungicides. Drought and heat waves are more and more frequent and they bring strong consequences for grape production and wine quality. Thus, defining drought tolerance level of resistant varieties that will be adopted in Occitanie and other French wine regions is crucial. In such a manner, this project will study physiological responses under water constraint and warm climate conditions of new INRA resistant varieties. It will be possible to classify them in function of their water use efficiency and aerial carbon balance and distribution in the short and long-term. Furthermore, we will analyze if the characteristic of VDQA varieties, in maturing grapes with low fermentable sugars, can be related to a lower vine water demand. This would imply that these varieties may present a favorable metabolism during water constraint conditions, while producing wines with lower alcohol content, which is an increasing tendency for the wine market. We dispose of different experiments, 2 with field-grown vines and 2 with potted vines, besides a 3 year database from the field experiment, which will help us better address our research questions.

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Rebecca Therby Vale (BPMP-Equipe HONUDE)

Combinatorial effects of nutrients on photosynthesis and ion accumulation

Variation of the nutrient availability leads to modifications on key processes such as photosynthesis and ion accumulation. Nutrient deficiency on photosynthesis has mainly been studied for single ion deficiency; such as the iron depletion which induces chlorosis. Surprisingly, joint iron and phosphate deficiencies results in a stay green phenotype in various plant species (i.e. O. sativa, Zea mays and Arabidopsis thaliana). This demonstrates the need to study photosynthesis parameters in different nutrient conditions. During my PhD I will study how nitrogen, phosphate and iron signaling are wired to modulate photosynthesis focusing on PSII activity. To do this I will explore the natural variation in Arabidopsis thaliana using a Genome wide association studies (GWAS) approach. This will allow me to identify new molecular players involved in the regulation of photosynthesis under multiple nutrient stress. This knowledge will help to understand the complex interactions between nutrients.
In the second project of my PhD I will study phosphate homeostasis. A screen performed in the team identified PHT1;3 (Phosphate Transporter 1;3) as a regulator of phosphate homoeostasis. The screen of the natural variability of A. thaliana shows different versions of the transporter depending on the accession. It seems that the phosphate concentration relies (at least partially) on this. Therefore, I will investigate the impact of PHT1;3 versions on phosphate homeostasis by characterizing the physiological impact of this variability. A better knowledge of nutrient homeostasis will help to identify traits limiting fertilizers inputs.

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Jugurta Bouidghaghen (LEPSE-Equipe MAGE)

Simulating maize yields in scenarios by combining phenomics, genomic prediction and crop modeling

Environmental adaptability and yield stability of cultivated varieties are important attributes for the sustainability of field cropping systems. Providing reliable predictions of varieties yields in different agro-climatic scenarios is of a major interest, since it allows to optimize farmers’ varietal choice at the field plot scale. For maize in particular, the recurrence of summer drought episodes due to climate change and variability challenges predictive approaches on their ability to predict genotype x environment (GxE) effects.
While genomic prediction is effective in simulating average variety performance based on genotyping information, it poorly predicts yield variations for each variety based on local environmental conditions (GxE interaction). My PhD aims to develop an approach that combines genomic prediction and phenomics with crop modeling, in order to get accurate simulations of cultivars yields in scenarios. Indeed, the tested approach will integrate (i) the measurement of genotype-dependent key physiological traits by phenomics, (ii) the genomic prediction of these traits, (iii) the environmental characterization of field plots, (iv) a crop model parameterized by the phenomic data.

Contacts IBIP :
Sabine Zimmermann (sabine.zimmermann@cnrs.fr)
Alexandre Martinière (alexandre.martiniere@cnrs.fr)
Florent Pantin (florent.pantin@supagro.fr)
Chantal Baracco (chantal.baracco@inrae.fr)