Aluminum-Induced Cell Wall Peroxidase Activity and Lignin Synthesis Are Differentially Regulated by Jasmonate and Nitric Oxide

Abstract

Cassia tora is an annual legume and cultivated as a traditional medicinal herb for multiple therapies including regulation of blood pressure and blood lipid. Because of naturally occurring acidic soils in southeastern China, this plant species may possess strategies for tolerance to low pH and aluminum toxicity. In the search for the regulatory basis of biochemical response to Al, cell wall-bound peroxidases, including lignin-generated peroxidases and NADH oxidases, were investigated in the root tips of C. tora. Activities of both types of peroxidases significantly increased with Al concentrations. Analysis with native PAGE also demonstrated the strong induction of cell wall peroxidases by Al. The Al-induced increasing activities of peroxidases were closely correlated with lignin accumulation and H 2O 2 production. The biochemical effect of exogenous nitric oxide (NO) and methyl jasmonic acid (MJ) was examined to investigate signal properties and lignin synthesis under Al stress. Application of MJ at 10 microM promoted root sensitivity to Al by activating apoplastic peroxidase activity and accumulating H 2O 2 and lignin, whereas the opposite action was found for NO. The sensitivity of apoplastic peroxidases under Al stress was associated with the cross-talk of MJ and NO signals. The analysis reveals that the activity of lipoxygenase (an enzyme for MJ biosynthesis), with its transcripts increased in Al-exposed roots, was depressed by NO exposure. The effect of MJ on intracellular NO production was also investigated. It is shown that NO staining with 4,5-diaminofluorescein diacetate fluorescence was intensified by Al but was suppressed by MJ. These results suggest that NO and MJ may interplay in signaling the cell wall peroxidase activity and lignin synthesis in the roots exposed to Al.

iTRAQ Protein Profile Analysis of Arabidopsis Roots Reveals New Aspects Critical for Iron Homeostasis

“…In addition, LAC-CASE7, annotated as being involved in lignin degradation, was strongly down-regulated both at the transcript and protein levels. Lignin biosynthesis is increased by a variety of stresses, including supraoptimal concentrations of Zn and copper, and by the presence of unfavorable metals such as cadmium, aluminum, and nickel (Mao et al, 2004;van de Mortel et al, 2006;Kovácik and Klejdus, 2008;Xue et al, 2008;Kovácik et al, 2009;Moura et al, 2010). Lignification alters cell wall properties and may serve to restrict the long-distance transport of these metals.…”

Analysis of apoplastic and symplastic antioxidant system in shallot leaves: Impacts of weak static electric and magnetic field

“…Unspecific PODs protect cells against damaging effects of H 2 O 2 during an oxidative-burst response which occurs as a result of cellular redox changes. Apoplastic PODs are bound to cell wall polymers by ionic or covalent bonds, and were reported to be easily released from the cell wall into the apoplast and play a critical role in regulating the wall stiffening process (De Pinto and De Gara, 2004), and many other functions related to their ROS scavenging activity (Xue et al, 2008) under normal and stress conditions. Our results show that EF application may impede cell wall lignification process by affecting chemical composition of apoplastic GPOD and some other related enzymes bound to cell wall polymers.…”

A MYB/ZML Complex Regulates Wound-Induced Lignin Genes in Maize

“…Consequently, several genes of the lignin pathway are induced by wounding and/or methyl jasmonate (MeJA) (Ellard-Ivey and Douglas, 1996;Bell-Lelong et al, 1997;Mizutani et al, 1997;Ehlting et al, 1999;Reymond et al, 2000;Devoto et al, 2005;Pauwels et al, 2008). In addition, the induction of MeJA cascade has been positively correlated with an increase in lignin content in several species, such as Bryonia dioica (Kaiser et al, 1994), Cassia tora (Xue et al, 2008), and rice (Oryza sativa; Tianpei et al, 2015).…”