Combinatorial Control of Floral Organ Identity by MADS-domain Transcription Factors

AbstractArabidopsis flower primordia give rise to floral organ primordia in stereotypical positions within four concentric whorls. Floral organ primordia in each whorl undergo distinct developmental programs to become one of four organ types (sepals, petals, stamens, and carpels). The Arabidopsis transcription factors AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6) play critical and partially overlapping roles during floral organogenesis. They are required for correct positioning of floral organ initiation, contribute to the specification of floral organ identity, and regulate the growth and morphogenesis of developing floral organs. To gain insight into the molecular means by which ANT and AIL6 contribute to floral organogenesis, we identified the genome-wide binding sites of both ANT and AIL6 in stage 3 flower primordia, the developmental stage at which sepal primordia become visible and class B and C floral homeotic genes are first expressed. AIL6 binds to a subset of ANT sites, suggesting that AIL6 regulates some but not all of the same target genes as ANT. ANT and AIL6 binding sites are associated with genes involved in many biological processes related to meristem and flower organ development. Comparison of genes associated with both ANT and AIL6 ChIP-Seq peaks and those differentially expressed after perturbation of ANT or AIL6 activity identified likely direct targets of ANT and AIL6 regulation. These include the floral homeotic genes APETALA3 (AP3) and AGAMOUS (AG) and four growth regulatory genes: BIG BROTHER (BB), ROTUNDIFOLIA3 (ROT3), ANGUSTIFOLIA3/GRF INTERACTING FACTOR (AN3/GIF1), and XYLOGLUCAN ENDOTRANSGLUCOLSYLASE/HYDROLASE9 (XTH9).One Sentence SummaryThe transcription factors ANT and AIL6 directly regulate genes involved in different aspects of flower development including genes that specify floral organ identity and those that regulate growth.

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Control of Floral Organ Identity by Homeotic MADS-Box Transcription Factors

Results and Problems in Cell Differentiation - Plant Promoters and Transcription Factors ◽

10.1007/978-3-540-48037-2_11 ◽

1994 ◽

pp. 235-258 ◽

Cited By ~ 29

Author(s):

Brendan Davies ◽

Zsuzsanna Schwarz-Sommer

Keyword(s):

Transcription Factors ◽

Floral Organ ◽

Mads Box ◽

Floral Organ Identity ◽

Organ Identity

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MIR172d Is Required for Floral Organ Identity and Number in Tomato

International Journal of Molecular Sciences ◽

10.3390/ijms22094659 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4659

Author(s):

Wanping Lin ◽

Suresh Kumar Gupta ◽

Tzahi Arazi ◽

Ben Spitzer-Rimon

Keyword(s):

Transcription Factors ◽

Transcriptional Repression ◽

De Novo ◽

Floral Organ ◽

Dependent Manner ◽

Loss Of Function ◽

Floral Organ Identity ◽

Organ Identity ◽

Unique Species ◽

Dose Dependent

MicroRNA172 (miR172) functions as a central regulator of flowering time and flower development by post-transcriptional repression of APETALA2-LIKE transcription factors. In the model crop Solanum lycopersicum (tomato), the miR172 family is still poorly annotated and information about the functions of specific members is lacking. Here, de-novo prediction of tomato miR172 coding loci identified seven genes (SlMIR172a-g), that code for four unique species of miR172 (sly-miR172). During reproductive development, sly-miR172s are differentially expressed, with sly-miR172c and sly-miR172d being the most abundant members in developing flowers, and are predicted to guide the cleavage of eight APETALA2-LIKE transcription factors. By CRISPR-Cas9 co-targeting of SlMIR172c and SlMIR172d we have generated a battery of loss-of-function and hypomorphic mutants (slmir172c-dCR). The slmir172c-dCR plants developed normal shoot but their flowers displayed graded floral organ abnormalities. Whereas slmir172cCR loss-of-function caused only a slight greening of petals and stamens, hypomorphic and loss-of-function slmir172dCR alleles were associated with the conversion of petals and stamens to sepaloids, which were produced in excess. Interestingly, the degrees of floral organ identity alteration and proliferation were directly correlated with the reduction in sly-miR172d activity. These results suggest that sly-miR172d regulates in a dose-dependent manner floral organ identity and number, likely by negatively regulating its APETALA2-like targets.

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