Effects of iron excess on cell viability and mitogen‐activated protein kinase activation in rice roots

Abstract

Iron is an essential micronutrient for normal growth and development of plants. However, at high concentrations, iron can become toxic to plants. Very little information is known about the molecular mechanism responsible for the regulation of plant growth by excess iron. The aim of this study was to investigate the signal transduction pathway activated by increasing concentrations (0.5, 1.0, and 2.5 mm) of iron. We showed that iron elicited a remarkable myelin basic protein (MBP) kinase activity. By Western blot and immunoprecipitation analysis, we suggested that iron-activated 42-kDa MBP kinase is a mitogen-activated protein kinase (MAPK). Cell death in rice roots due to iron toxicity was investigated using inhibitors of signal molecules known to regulate programmed cell death in plants. Phenylarsine oxide (PAO) and sodium orthovanadate, known inhibitors of tyrosine phosphatase, reduced iron-induced root cell death, but cantharidin and endothall twoserine/threonine phosphatase inhibitor enhanced iron-induced root cell death. Moreover, our results revealed that H þ -ATPase might participate in iron-induced cell death. These results suggested that the MAPK, reactive oxygen species, protein phosphatase, and H þ -ATPase might function in the plant iron-triggered signaling pathway in rice roots.

Impacts of silicon nutrition on growth and nutrient status of rice plants grown under varying zinc regimes

“…The iron content and concentration of roots and seeds increased significantly in Zn-deficient plants. This may intensify the stressful conditions on plant through the induction of ROS production (Tsai and Huang 2006). The iron uptake in rice competes with Zn uptake as it is carried out by similar metal transporters (ZIP transporters) (Masuda et al 2012).…”

Leaf morphoanatomy of species tolerant to excess iron and evaluation of their phytoextraction potential

“…Although iron is a vital micronutrient for plant growth and development (Connolly et al 2003;Connolly and Guerinot 2002), its high content in the substrate can affect cellular homeostasis and cause toxic effects (Williams et al 2000;Ducic and Polle 2005) like oxidative stress in cells, which may result in tissue damage (Becana et al 1998;Tsai and Huang 2006).…”

Possible involvement of MAP kinase pathways in acquired metal-tolerance induced by heat in plants

“…In plants, Zhang and Liu (2001) demonstrated that increases of salicylate-induced protein kinase (SIPK) activity alone induce defense gene activation and cell death in tobacco. Previously, it was also found that Cd, Cu, Zn, and Fe could activate MAPKs phosphorylation in rice and alfalfa plants (Yeh et al 2003(Yeh et al , 2007Jonak et al 2004;Lin et al 2005;Tsai and Huang 2006). Moreover, the Cu-induced MAP kinase activation required the involvement of NADPH oxidases, Ca 2+ -dependent protein kinase (CDPK) and phosphatidylinositol 3-kinase (PI3 kinase).…”