IAL   21557
INSTITUTO DE AGROBIOTECNOLOGIA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The Arabidopsis transcription factor AtHB1 plays a role in iron homeostasis
Autor/es:
FACUNDO ALIHUEN ROMANI; MATIAS CAPELLA; PAMELA ANAHÍ RIBONE; RAQUEL LÍA CHAN
Lugar:
Foz do Iguaçu
Reunión:
Congreso; 11th International Congress of Plant Molecular Biology; 2015
Resumen:
Iron is an essential nutrient for plant growth and development. Higher plants have evolved sophisticated strategies to obtain this element from the soil. Iron homeostasis in plants is highly regulated at transcriptional and posttranscriptional level in the key molecular components. In particular, Iron-Regulated Transporter1 (IRT1) is the most important transporter for ferrous ironuptake and is regulated by iron availability.The homeodomain-leucine zipper (HD-Zip) family of transcription factors (TFs) is unique to plants. Among Arabidopsis HD-Zip subfamily I members, AtHB1 has a role in hypocotyls elongation in response to light conditions. The analysis of the transcriptome of athb1 mutant plants by RNA-Seq, revealed the differential expression of many genes involved in the iron homeostasis, including IRT1, FER1 and FRO2. Transient transformation of tobacco leaves with IRT1 promoter directing GUS and 35S::AtHB1 suggested that AtHB1 directly repress IRT1 expression. The analysis of Arabidopsis plants transformed with AtHB1 promoter directing GUS expression indicated a sensitive regulation of AtHB1 expression by iron concentration. Further analysis showed that the athb1-1 mutant plants exhibit an increased tolerance to iron deficiency conditions and higher chlorophyll concentration than wild type plants in these conditions. AtHB1 would function as a repressor of IRT1 expression to prevent transcript overaccumulation when IRT1 is induced by iron deficiency. This is the first time that a member of this family of TFs is associated with iron homeostasis and also the first time that a transcriptional negative regulator ofIRT1 is identified.