Zhang Yi-Kai, Zhu De-Feng, Zhang Yu-Ping, Chen Hui-Zhe, Xiang Jing, Lin Xian-Qing
State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, Zhejiang, 310006, P. R. China.
PLoS One. 2015 Feb 26;10(2):e0116971. doi: 10.1371/journal.pone.0116971. eCollection 2015.
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.
土壤酸化是当前水稻生产中的主要问题。在此，我们在水培系统中，于pH值为3.5、4.5和5.5的条件下，研究了低pH对水稻幼苗（Oryza sativa L.）根系生长、活性氧代谢、质膜功能以及相关基因转录水平的影响。本试验中有两个杂交水稻品种，包括甬优12（YY12，粳型杂交稻）和中浙优1号（ZZY1，籼型杂交稻）。较高的H⁺活性显著降低了根长、细根比例和干物质产量，但诱导了过氧化氢（H₂O₂）的大量积累，并导致两个品种根系严重的脂质过氧化。在低pH处理两周后，YY12和ZZY1根系中铜/锌超氧化物歧化酶1（Cu/Zn SOD1）、铜/锌超氧化物歧化酶2（Cu/Zn SOD2）、过氧化氢酶A（CATA）和过氧化氢酶B（CATB）基因的转录水平显著下调。同时，在pH 3.5时，根系中P型Ca²⁺ - ATP酶的表达显著降低。强根际酸化显著抑制了两个品种中抗氧化酶（SOD、CAT）和质膜（PM）Ca²⁺ - ATP酶的活性。然而，与对照相比，在H⁺胁迫下抗坏血酸过氧化物酶1（APX1）和质膜H⁺ - ATP酶同工型7的表达水平上调。APX和质膜H⁺ - ATP酶显著更高的活性可能有助于水稻根系适应低pH。
