Ph D recently defended at IPS2

Hadi KHARESTANI

Engineering of the eIF4E gene for resistance against Potyviridae viruses in melon using genome editing

Keywords: Melon, genetic transformation, base editing, resistance to virus.

Melon (Cucumis melo L.) is a recalcitrant species for genetic transformation. During this PhD thesis, hosted by the FLOCAD team at IPS2, a protocol for introducing a target gene and regeneration of melon was engineered in Charentais and Khatooni melon cultivars. Next, five CRISPR guide RNAs were designed to disrupt the binding of the viral RNA to the eukaryotic initiation factor 4E protein, CmeIF4E. Seventeen edited plants were regenerated among which seven harboured edited alleles with potential deleterious effects on the CmeIF4E function. The homozygous plant edited at the amino acid position 320 was challenged with the Apple Latent Spherical Virus, ALSV, and showed increased resistance.

January 26, 2022

Supervisors: Adnane Boualem and Mohammad Sadegh Sabet

Adrien SPECK

Genetic mapping and selection method for resistance to flax pests (Linum usitatissimum)

Keywords: flax, Powdery mildew, Resistance, GWAS, QTL.

Powdery mildew is one of the most important diseases of flax. Genetic resistance of varieties is critical for the control of this disease, but very few resistance genes have been identified so far. To access to a marker assisted selection / genomic selection program, several studies have been carried out: (i) The set-up of a worldwide diversity panel composed of 311 flax genotypes, (ii) The development of a methodology for genotyping by sequencing leading to the identification of 1,693,910 high-quality SNPs, and finally, (iii) The analysis of the population structure which allowed to identify four major genetic groups, separating oil flax accessions originating from America/Europe from those of Asia/Middle-East, and fiber flax accessions originating from Eastern Europe from those of Western Europe. GWAS analyses revealed the presence of eight QTLs containing promising candidate genes for flax resistance to powdery mildew.

February 10, 2022

Supervisors: Jérôme Enjalbert, Valérie Geffroy and Jean-Paul Trouvé

Marine GUILCHER

Functional analysis of the GUN1 protein, its partners, and their roles in the retrograde signals of the chloroplast

Keywords: Retrograde signaling, pentatricopeptide repeat protein, plastid genome expression

Coordination between the expression of the nuclear and plastid genomes relies on the communication between these two cellular structures. GUN1 has been identified as a major component of retrograde (plastid-to-nucleus) signaling; however, its molecular function remains elusive. GUN1 takes part of the pentatricopeptide repeat protein (PPR) family which is specialized in interactions with RNA. In the context of this PhD work, carried out within the OGE team at IPS2, we could identify by coupling phylogenetic and bioinformatics approaches a putative RNA binding site for the GUN1 PPR protein. By studying the transcriptome of gun1 mutants, we could highlight a molecular default potentially induced by the direct interaction between GUN1 and its RNA target.

March 8, 2022

Supervisors: Claire Lurin and Etienne Delannoy

13/05/2022