The F-box protein UFO controls flower development by redirecting the master transcription factor LEAFY to new cis-elements

Abstract

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GmUFO1 Regulates Floral Organ Number and Shape in Soybean

“…Even the most severe mutant phenotype of Gmufo did not show complete replacement of the second whorl organ with sepals, and sepal-like petals mostly appeared on the ventral part. Previous studies have documented that by controlling the interaction between UFO and LFY, the UFO gene can regulate the downstream targets of AP3 and PI, thereby affecting the flower phenotype [8]. In this context, the interaction among the UFO, ABC, LFY, WUS, and CAL genes has been explored previously in different studies at the petal formation stage.…”

“…LFY controls the temporal specificity of AP3 expression, while UFO and AP1 control the spatial pattern [5,6]. UFO has been reported to interact with the SCF E3 ubiquitin ligase subunits, ASK1 and CUL1, as well as subunits of the COP9 signalosome, which suggest the possible role of UFO in the ubiquitination of proteins that are involved in flower development [7,8]. The interaction of the UFO and ASK1 proteins may enhance the degradation of the downstream B functional gene AP3 and the PI inhibitor by the UFO gene, resulting in the activation and production of the B functional gene [5,9,10].…”

“…Strong loss-of-function mutations in the UFO gene cause flower abnormalities in all whorls. In sepals and petals, homeotic changes, organ number, and phyllotaxis are the most severe [8,11]. Sepals replace petals, and carpels replace stamens; however, mosaic organs are also prevalent in both whorls of the ufo mutant.…”

Thinking outside the F‐box: how UFO controls angiosperm development

“…Revisiting UFO-LFY targets regulating floral organ development The role of UFO-LFY on floral organ development is established in most angiosperm species, and several target genes have been identified (see above). In Arabidopsis, such targets include the B genes AP3 for which functional LUBS were identified in their promoter sequence, explaining their regulation by the UFO-LFY complex (Rieu et al, 2023). Functional LUBS sites are expected to be found in the regulatory sequences of genes under the control of the UFO-LFY complex in many other plants, in particular B, C or E homeotic genes.…”

“…In contrast to a previous study (Risseeuw et al ., 2013), it was recently found that overexpression of a truncated UFO version lacking the F‐box domain (i.e. unable to participate in a SCF complex) largely complemented a strong Arabidopsis ufo allele, restoring petal and stamen development (Rieu et al ., 2023). Hence, the connection of UFO to an E3 ligase complex appears partially dispensable, at least in Arabidopsis.…”