The unequal functional redundancy of ArabidopsisINCURVATA11andCUPULIFORMIS2is not dependent on genetic background

Abstract

ABSTRACTThe paralogous genesINCURVATA11(ICU11) andCUPULIFORMIS2(CP2) encode components of the epigenetic machinery in Arabidopsis and belong to the 2-oxoglutarate and Fe (II)-dependent dioxygenase superfamily. We previously inferred unequal functional redundancy betweenICU11andCP2from a study of the synergistic phenotypes of the double mutant and sesquimutant combinations oficu11andcp2mutations, although they represented mixed genetic backgrounds. To avoid potential confounding effects arising from different genetic backgrounds, we generated theicu11-5andicu11-6mutants via CRISPR/Cas genome editing in the Col-0 background and crossed them tocp2mutants in Col-0. The resulting mutants exhibited a postembryonic-lethal phenotype reminiscent of strongembryonic flower(emf) mutants. Double mutants involvingicu11-5and mutations affecting epigenetic machinery components displayed synergistic phenotypes, whereascp2-3did not besidesicu11-5. Our results confirmed the unequal functional redundancy betweenICU11andCP2and demonstrated that it is not allele or genetic background specific. An increase in sucrose content in the culture medium partially rescued the post-germinative lethality oficu11 cp2double mutants and sesquimutants, facilitating the study of their morphological phenotypes throughout their life cycle, which include floral organ homeotic transformations. We thus established that theICU11-CP2module is required for proper flower organ identity.