Identification of iron-deficiency-inducible genes encoding transcription-related proteins in graminaceous plants

摘要

Many genes are up-regulated by iron (Fe) deficiency in graminaceous plants. However, very little is known about the regulation mechanisms of these Fe deficiency-inducible genes. To identify potential gene regulators, we examined transcription factors and putative transcription-related proteins whose genes were also up-regulated by Fe deficiency. The iron-related transcription factors (IROs) 1 and 2 were proteins found to be well conserved in barley and rice and whose expression was induced by Fe deficiency. IRO1 is a basic leucine zipper protein and IRO2 is a basic helix-loop-helix protein. Fe deficiency increased IRO1 expression in the roots of both barley and rice. In contrast, IRO2 expression was strongly induced in barley and rice in both roots and shoots. As each IRQ protein was similarly expressed in both barley and rice, each was thought to have a common function in graminaceous plants under Fe-deficient conditions. Samples from a time course of Fe-deficient plants were gene-profiled using a rice 22K oligo microarray. Several genes for putative transcription factors and transcription-related proteins were revealed to be up-regulated by Fe deficiency in rice. Products of some of these genes could play important roles in transcriptional regulation under Fe-deficient conditions in rice.