MNB1 gene is involved in regulating the iron-deficiency stress response in Arabidopsis thaliana

Abstract

Abstract Background Iron (Fe) is an essential mineral element that involves in many biological processes important for most plants growth and development. Fe-deficiency induces a complex series of responses in plants, involving physiological and developmental changes, to increase Fe uptake from soil. However, the molecular mechanism involved in plant Fe-deficiency is not well understood. Results Here, we found that the MNB1 (mannose-binding-lectin 1) gene is involved in the regulation of Fe-deficiency stress response in Arabidopsis thaliana . The expression abundance of MNB1 was inhibited by Fe-deficiency stress. Knockout of MNB1 led to enhanced Fe accumulation and tolerance, whereas the MNB1 -overexpressing plants were sensitive to Fe-deficiency stress. Under conditions of normal and Fe-deficiency, lower H 2 O 2 concentrations were detected in mnb1 mutant plants compared to wild type. On the contrary, higher H 2 O 2 concentrations were found in MNB1 -overexpressing plants, which was negatively correlated with malondialdehyde (MDA) levels. Furthermore, in mnb1 mutants, the transcription level of the Fe uptake- and translocation-related genes, FIT , IRT1 , FRO2 , ZIF , FRD3 , NAS4 , PYE and MYB72 , were considerably elevated during Fe-deficiency stress, resulting in enhanced Fe uptake and translocation, thereby increasing Fe accumulation. Conclusions Together, our findings show that the MNB1 gene negatively controls the Fe-deficiency response in Arabidopsis via modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling pathway, thereby affecting the expression of Fe uptake- and translocation-related genes.