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

• Published in: Frontiers in plant science Vol. 14; p. 1239093
• Main Authors: Nadi, Riad, Juan-Vicente, Lucía, Mateo-Bonmatí, Eduardo, Micol, José Luis
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 15-11-2023
• Subjects: 2OGD; Arabidopsis thaliana; CRISPR/Cas9; CUPULIFORMIS2; epigenetic machinery; ICU11; Plant Science
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2023.1239093

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