Department of Agronomy, National Taiwan University, Taipei, Taiwan, ROC.
J Plant Physiol. 2013 Jan 1;170(1):63-9. doi: 10.1016/j.jplph.2012.08.015. Epub 2012 Sep 16.
Lateral roots (LRs) play important roles in increasing the absorptive capacity of roots as well as to anchor the plant in the soil. Therefore, understanding the regulation of LR development is of agronomic importance. In this study, we examined the effect of methyl jasmonate (MJ) on LR formation in rice. Treatment with MJ induced LR formation and heme oxygenase (HO) activity. As well, MJ could induce OsHO1 mRNA expression. Zinc protoporphyrin IX (the specific inhibitor of HO) and hemoglobin [the carbon monoxide/nitric oxide (NO) scavenger] reduced LR formation, HO activity and OsHO1 expression. LR formation and HO activity induced by MJ was reduced by the specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-oxide. The effects of Ca(2+) chelators, Ca(2+)-channel inhibitors, and calmodulin (CaM) antagonists on LR formation induced by MJ were also examined. All these inhibitors were effective in reducing the action of MJ. However, Ca(2+) chelators and Ca(2+) channel inhibitors induced HO activity when combining with MJ further. It is concluded that Ca(2+) may regulate MJ action mainly through CaM-dependent mechanism.
侧根（LRs）在增加根系的吸收能力以及固定植物在土壤中方面起着重要作用。因此，了解 LR 发育的调控机制具有农业重要性。在这项研究中，我们研究了茉莉酸甲酯（MJ）对水稻 LR 形成的影响。MJ 处理诱导了 LR 的形成和血红素加氧酶（HO）的活性。此外，MJ 可以诱导 OsHO1 mRNA 的表达。锌原卟啉 IX（HO 的特异性抑制剂）和血红蛋白[一氧化碳/一氧化氮（NO）清除剂]降低了 LR 的形成、HO 的活性和 OsHO1 的表达。MJ 诱导的 LR 形成和 HO 活性被特异性的 NO 清除剂 2-(4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧-氧化物降低。还研究了 Ca(2+)螯合剂、Ca(2+)通道抑制剂和钙调蛋白（CaM）拮抗剂对 MJ 诱导的 LR 形成的影响。所有这些抑制剂都能有效降低 MJ 的作用。然而，Ca(2+)螯合剂和 Ca(2+)通道抑制剂在与 MJ 结合时进一步诱导了 HO 的活性。因此，结论是 Ca(2+)可能主要通过 CaM 依赖性机制调节 MJ 的作用。
