Low pH-Induced Changes of Antioxidant Enzyme and ATPase Activities in the Roots of Rice (Oryza sativa L.) Seedlings

Abstract

Soil acidification is the main problem in the current rice production. Here, the effects of low pH on the root growth, reactive oxygen species metabolism, plasma membrane functions, and the transcript levels of the related genes were investigated in rice seedlings (Oryza sativa L.) in a hydroponic system at pH 3.5, 4.5, and 5.5. There were two hybrid rice cultivars in this trial, including Yongyou 12 (YY12, a japonica hybrid) and Zhongzheyou 1 (ZZY1, an indica hybrid). Higher H+ activity markedly decreased root length, the proportion of fine roots, and dry matter production, but induced a significant accumulation of hydrogen peroxide (H2O2), and led to serious lipid peroxidation in the roots of the two varieties. The transcript levels of copper/zinc superoxide dismutase 1 (Cu/Zn SOD1), copper/zinc superoxide dismutase 2 (Cu/Zn SOD2), catalase A (CATA) and catalase B (CATB) genes in YY12 and ZZY1 roots were significantly down-regulated after low pH exposure for two weeks. Meanwhile, a significant decrease was observed in the expression of the P-type Ca2+-ATPases in roots at pH 3.5. The activities of antioxidant enzymes (SOD, CAT) and plasma membrane (PM) Ca2+-ATPase in the two varieties were dramatically inhibited by strong rhizosphere acidification. However, the expression levels of ascorbate peroxidase 1 (APX1) and PM H+-ATPase isoform 7 were up-regulated under H+ stress compared with the control. Significantly higher activities of APX and PM H+-ATPase could contribute to the adaptation of rice roots to low pH.

High-throughput Screening of Rice for Nitrosative-stress Response and the Identification of Effective pH Range for Nitric Oxide Donor S-Nitrocysteine

“…According to previous research, gene expression of APX1 was up-regulated to contribute to the adaption in low pH condition. Meanwhile, CATA and CATB gene expression were significantly downregulated after low pH exposure (Zhang et al, 2015). In our results, APX1 and CATA gene expression were showed parallel patterns.…”

Critical factors besides treatment dose and duration need to be controlled in Pb toxicity tests in plant cell suspension cultures

“…Acidity was the factor affecting the toxicity of Pb, rather than changes in light intensity. As suggested in studies on Oryza sativa [16], low pH can affect the cell membrane, which forms an effective barrier to transport of ions into the cell via high H + activity, which inhibits Ca 2+ -ATPase activity, reducing Pb 2+ transport into the cell. Hydrogen ions may compete with metal cations for ligand binding sites on the cell and lessen the metal's interaction with cells [17].…”

Alleviation of proton toxicity by nitrate uptake specifically depends on nitrate transporter 1.1 in Arabidopsis

“…Acid soils comprise up to c. 50% of the world's potentially arable lands (Kochian et al, 2015). High proton (H + ) concentrations in acid soils are highly rhizotoxic to plants (Koyama et al, 1995;Iuchi et al, 2007;Zhang et al, 2015). A low soil pH also increases solubilization of metals, such as aluminum (Al 3+ ), which is another ion that is highly toxic to plants.…”