Detection and characterization in tomato of variants in genes involved in xylem flows (Tom-tom)

Coordination: Mylène Durand-Tardif

Industrial partner: Gautier Semences

The TomTom project had the objective to obtain tomato lines with a higher Water Use Efficiency. To do so, orthologues of two Arabidopsis genes (AtESK1, AtKAK), implied in xylem formation or maintenance had to be isolated as well as TILLING variants. Xylem of the variants had to be characterized as well as their response to drought. Triple and double mutants might be required if there is functional redundancy for the multiple orthologues. The URGV isolated lines with SNP in potential KAK orthologues in tomato. Gautier Semences isolated and multiplied homozygous lines for Lekak1 and Lekak2 mutants. IJPB had the task to characterised these mutant lines: morphometry and growth performances under control and drought conditions, structure and composition of the xylem vessels, trichomes observation and stem hydraulic conductivity measurements. Drought response of Lekak1 and Lekak2 has been observed, thanks to a test performed on plantlets, adapted from Arabidopsis. Four mutant lines gave promising results i.e. performances under drought are favourable and/or a significant Genotype*Treatment interaction between the mutant and its hemizygous wild-type line was observed for a few characters. These mutants have been incorporated in a field drought test in Morocco, driven by Gautier Semences, to study yield and fruit quality. TomTom reinforced the cooperation between Gautier Semences and IJPB and we keep permanent watch of the funding opportunities to study double and triple Leesk Lekak mutants.