The transcription factors BEL1 and SPL are required for cytokinin and auxin signaling during ovule development in Arabidopsis.
Hormones, such as auxin and cytokinin, are involved in the complex molecular network that regulates the coordinated development of plant organs. Genes controlling ovule patterning have been identified and studied in detail; however, the roles of auxin and cytokinin in ovule development are largely unknown. Here we show that key cytokinin pathway genes, such as isopentenyltransferase and cytokinin receptors, are expressed during ovule development. Also, in a cre1-12 ahk2-2 ahk3-3 triple mutant with severely reduced cytokinin perception, expression of the auxin efflux facilitator PIN-FORMED 1 (PIN1) was severely reduced. In sporocyteless/nozzle (spl/nzz) mutants, which show a similar phenotype to the cre1-12 ahk2-2 ahk3-3 triple mutant, PIN1 expression is also reduced. Treatment with the exogenous cytokinin N(6)-benzylaminopurine also altered both auxin distribution and patterning of the ovule; this process required the homeodomain transcription factor BELL1 (BEL1). Thus, this article shows that cytokinin regulates ovule development through the regulation of PIN1. Furthermore, the transcription factors BEL1 and SPL/NZZ, previously described as key regulators of ovule development, are needed for the auxin and cytokinin signaling pathways for the correct patterning of the ovule.
Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy.
Stefano
S
Bencivenga
Sara
S
Simonini
Eva
E
Benková
Lucia
L
Colombo
D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D019521:Body Patterning; D003583:Cytokinins / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005838:Genotype; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D056771:Ovule / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D018520:Plant Shoots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; C097235:BEL1 protein, Arabidopsis; D003583:Cytokinins; D018398:Homeodomain Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D009687:Nuclear Proteins; C116363:PIN1 protein, Arabidopsis; D010937:Plant Growth Regulators; D012097:Repressor Proteins; C416221:SPL protein, Arabidopsis; D014157:Transcription Factors