Department of Agronomy, National Chung Hsing University, Taichung 40227, Taiwan.
Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan; Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
J Plant Physiol. 2018 Dec;231:374-382. doi: 10.1016/j.jplph.2018.10.019. Epub 2018 Oct 25.
The methionine residues of proteins are the preferred targets of oxidation by reactive oxygen species resulting in the formation of methionine sulfoxide (MetSO), which impairs protein function. Methionine sulfoxide reductase A and B (MSR) catalyze the reduction of the MetSO S and R epimers back to Met residues, respectively. The roles of abscisic acid (ABA) and nitric oxide (NO) on the transcript levels of methionine sulfoxide reductase (MSR; EC 1.8.4.6) in the roots of 2-d-old etiolated rice (Oryza sativa L.) seedlings exposed to NaCl were examined. The OsMSR transcript levels increased upon exposure to NaCl, which increased as the NaCl concentrations increased. Fluridone (Flu) pretreatment inhibited the increases in ABA and NO contents and the OsMSRA4, OsMSRA5, OsMSRB1.1, OsMSRB3 and OsMSRB5 transcripts by NaCl, while ABA application reversed the effects of Flu. Flu did not affect the OsMSRA2 and OsMSRB1.2 transcripts. The application of the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5,-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), to NaCl-treated roots inhibited the increase in all of the OsMSRs transcripts with the exception of OsMSRB1.2. Treatment with the NO donor sodium nitroprusside (SNP) increased all the OsMSRs transcripts. The inhibitory effect of Flu on the increase of the OsMSRA4, OsMSRA5, OsMSR1.1, OsMSRB 3, and OsMSRB5 transcripts in the NaCl-treated roots was reversed by SNP. cPTIO inhibited the expression of all the OsMSR genes. The OsMSRA2.1 and OsMSRB1.2 transcripts can be increased by SNP. The Flu-inhibited internal ABA contents cannot be recovered by treatment with cPTIO or SNP. In addition, NaCl-induced NO production can be divided into ABA-dependent and ABA-independent routes. Therefore, the ABA-dependent NO route regulated the expression of OsMSRA4, OsMSRA5, OsMSRB1.1, OsMSRB 3, and OsMSRB5 in the NaCl-treated rice roots, while the ABA-independent NO pathway modulated OsMSRA2.1, and the ABA-independent and NO-independent pathway modulated OsMSRB1.2 expression in response to NaCl treatment.
蛋白质的蛋氨酸残基是活性氧物种氧化的首选靶标，导致蛋氨酸亚砜（MetSO）的形成，从而损害蛋白质功能。甲硫氨酸亚砜还原酶 A 和 B（MSR）分别催化 MetSO S 和 R 差向异构体还原回 Met 残基。研究了脱落酸（ABA）和一氧化氮（NO）对盐胁迫下 2 天大的黄化水稻（Oryza sativa L.）幼苗根中蛋氨酸亚砜还原酶（MSR；EC 1.8.4.6）转录水平的影响。暴露于 NaCl 会增加 OsMSR 的转录水平，随着 NaCl 浓度的增加而增加。氟啶酮（Flu）预处理抑制了 ABA 和 NO 含量以及 OsMSRA4、OsMSRA5、OsMSRB1.1、OsMSRB3 和 OsMSRB5 转录物的增加，但 ABA 的应用逆转了 Flu 的作用。Flu 不影响 OsMSRA2 和 OsMSRB1.2 转录物。向 NaCl 处理的根中应用 NO 清除剂 2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物（cPTIO），除了 OsMSRB1.2 之外，所有 OsMSRs 转录物的增加均受到抑制。用硝普钠（SNP）处理增加了所有 OsMSRs 转录物。SNP 逆转了 Flu 对 NaCl 处理的根中 OsMSRA4、OsMSRA5、OsMSR1.1、OsMSRB3 和 OsMSRB5 转录物增加的抑制作用。cPTIO 抑制所有 OsMSR 基因的表达。SNP 可增加 OsMSRA2.1 和 OsMSRB1.2 转录物。用 cPTIO 或 SNP 处理不能恢复 Flu 抑制的内部 ABA 含量。此外，NaCl 诱导的 NO 产生可分为 ABA 依赖和 ABA 独立途径。因此，ABA 依赖的 NO 途径调节盐胁迫下水稻根中 OsMSRA4、OsMSRA5、OsMSRB1.1、OsMSRB3 和 OsMSRB5 的表达，而 ABA 独立的 NO 途径调节 OsMSRA2.1 的表达，以及 ABA 独立和 NO 独立途径调节 OsMSRB1.2 的表达对 NaCl 处理的反应。
