AUTHOR=Nadi Riad , Juan-Vicente Lucía , Mateo-Bonmatí Eduardo , Micol José Luis 

TITLE=The unequal functional redundancy of Arabidopsis INCURVATA11 and CUPULIFORMIS2 is not dependent on genetic background

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1239093

DOI=10.3389/fpls.2023.1239093

ISSN=1664-462X

ABSTRACT=<p>The paralogous genes <italic>INCURVATA11</italic> (<italic>ICU11</italic>) and <italic>CUPULIFORMIS2</italic> (<italic>CP2</italic>) 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 between <italic>ICU11</italic> and <italic>CP2</italic> from a study of the synergistic phenotypes of the double mutant and sesquimutant combinations of <italic>icu11</italic> and <italic>cp2</italic> mutations, although they represented mixed genetic backgrounds. To avoid potential confounding effects arising from different genetic backgrounds, we generated the <italic>icu11-5</italic> and <italic>icu11-6</italic> mutants via CRISPR/Cas genome editing in the Col-0 background and crossed them to <italic>cp2</italic> mutants in Col-0. The resulting mutants exhibited a postembryonic-lethal phenotype reminiscent of strong <italic>embryonic flower</italic> (<italic>emf</italic>) mutants. Double mutants involving <italic>icu11-5</italic> and mutations affecting epigenetic machinery components displayed synergistic phenotypes, whereas <italic>cp2-3</italic> did not besides <italic>icu11-5</italic>. Our results confirmed the unequal functional redundancy between <italic>ICU11</italic> and <italic>CP2</italic> and 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 of <italic>icu11 cp2</italic> double mutants and sesquimutants, facilitating the study of their morphological phenotypes throughout their life cycle, which include floral organ homeotic transformations. We thus established that the <italic>ICU11-CP2</italic> module is required for proper flower organ identity.</p>