Tolerance and Response to Iron Defficiency in Plants

Most living organisms require iron for growth and development, and the iron absorbed by plants represents a major source of iron in animal and human diet. Iron is very much abundant in mineral soils; however it is sparingly soluble in aerobic conditions and high pH. Scientists have known that plants induce iron utilization systems under iron deficiency. The exact molecular mechanism of the systems, however, remains unknown.

Scientists from the Tokyo University have discovered a transcription factor, IDEF1, that binds to a specific DNA sequence previously shown to respond during conditions of low iron availability. Transcription factors (TF) are protein that binds specific regions of the DNA. TF binding can either promote or inhibit the expression of certain genes. When the gene coding for IDEF1 was introduced to rice, the transgenic lines exhibited substantial tolerance to iron deficiency. IDEF1 expression was also found to promote the activation of related iron deficiency-responsive proteins, suggesting the presence of a sequential gene regulatory network. Manipulation of IDEF1 can provide approaches to produce crops tolerant to conditions of low iron availability, as in calcareous soil.

The abstract of the paper published by PNAS is available at http://www.pnas.org/cgi/content/abstract/104/48/19150 Subcribers can access the full paper at  http://www.pnas.org/cgi/reprint/104/48/19150