Iron assimilation and transcription factor controlled synthesis of riboflavin in plants.
Iron homeostasis is vital for many cellular processes and requires a precise regulation. Several iron efficient plants respond to iron starvation with the excretion of riboflavin and other flavins. Basic helix-loop-helix transcription factors (TF) are involved in the regulation of many developmental processes, including iron assimilation. Here we describe the isolation and characterisation of two Arabidopsis bHLH TF genes, which are strongly induced under iron starvation. Their heterologous ectopic expression causes constitutive, iron starvation independent excretion of riboflavin. The results show that both bHLH TFs represent an essential component of the regulatory pathway connecting iron deficiency perception and riboflavin excretion and might act as integrators of various stress reactions.
Vorwieger
A
A
Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, 06466, Gatersleben, Germany.
Gryczka
C
C
Czihal
A
A
Douchkov
D
D
Tiedemann
J
J
Mock
H-P
HP
Jakoby
M
M
Weisshaar
B
B
Saalbach
I
I
Bäumlein
H
H
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D012256:Riboflavin / Q000378:metabolism; D036226:Seedlings; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D007501:Iron; D012256:Riboflavin; C521772:bHLH38 protein, Arabidopsis; C521773:bHLH39 protein, Arabidopsis