AUXIN RESPONSE FACTOR3 Integrates the Functions of AGAMOUS and Auxin to Repress Cytokinin Biosynthesis and Signaling in Floral Meristem Determinacy
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ABSTRACT: Successful floral meristem (FM) determinacy is critical for the subsequent reproductive development and life cycle. Although phytohormones cytokinin and auxin interact to coordinately regulate many aspects of plant development, whether, if so how, cytokinin and auxin function in FM determinacy remain unclear. Here we show that the homeostasis of cytokinin is critical for the FM determinacy. Auxin promotes the expression of AUXIN RESPONSE FACTOR3 (ARF3) to repress cytokinin activity in FM determinacy. We found that ARF3 represses the expression of the ISOPENTENYLTRANSFERASE (IPT) family genes directly and the LONELY GUY (LOG) family genes indirectly, whose products are enzymes required for cytokinin biosynthesis. Furthermore, ARF3 directly inhibits the expression of ARABIDOPSIS HISTIDINE KINASE4 (AHK4), one of cytokinin receptor genes, to depress cytokinin activity. Genome-Wide Transcriptional Profiling reveals multiple functions of ARF3 in flower development. Consequently, ARF3 controls cell division by regulating cell cycle genes expression through cytokinin. Eventually, we show that AGAMOUS (AG) dynamically regulates the expression of ARF3 and IPTs resulting in coordinated regulation of FM maintenance and termination through cell division. Therefore, our findings reveal the molecular linkage between phytohormones auxin/cytokinin and AG in FM determinacy and shed light on the mechanisms of FM maintenance and termination.
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE103054 | GEO | 2018/08/24
REPOSITORIES: GEO
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