AtrbohD and AtrbohF negatively regulate lateral root development by changing the localized accumulation of superoxide in primary roots of Arabidopsis
AtrbohD and AtrbohF negatively regulate lateral root development by changing the localized accumulation of superoxide in primary roots of Arabidopsis
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DOI：
10.1007/s00425-014-2204-1
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发表时间：
2015-03-01
期刊：
影响因子：
4.3
通讯作者：
Hao, Fu Shun
中科院分区：
文献类型：
--
作者：
Li, Ning;Sun, Lirong;Hao, Fu Shun
NADPH氧化酶AtrbohD和AtrbohF以不依赖生长素的方式改变过氧化物酶活性并增加拟南芥初生根中超氧化物的局部生成，从而负向调节侧根发育。NADPH氧化酶亚基AtrbohD和AtrbohF在调节拟南芥的生长、发育和胁迫反应中发挥着关键作用。然而，它们是否调节侧根（LR）的形成尚未得到解决，并且该过程背后的详细机制仍未得到解答。在这里，我们发现两个无效双突变体 atrbohD1/F1 和 atrbohD2/F2（其中 AtrbohD 和 AtrbohF 基因均被破坏）具有比野生型（WT）或单突变体 atrbohD1 和 atrbohF1 显着更高的 LR 密度。与WT相比，双突变体表现出早期出现的LR和侧根原基（LRP）密度的增加。出乎意料的是，相对于WT，双突变体中含有LRs的主根成熟区域中超氧化物(O-2(-))的产生显着增加，但过氧化氢的产生不显着增加。进一步的实验表明，O-2（-）的局部积累导致双突变体中LR密度的增加。此外，AtrbohD和AtrbohF的缺乏导致成熟根区过氧化物酶活性显着增加，这有助于O-2（-）的局部积累和双突变体中LR密度的升高。此外，就LR形成而言，双突变体对外源生长素萘乙酸或生长素转运抑制剂1-N-萘基邻苯二甲酸不敏感。 atrbohD1/F1 体内 LRP 的生长素反应也与 WT 相似。综上所述，这些结果表明 AtrbohD 和 AtrbohF 通过以不依赖生长素的方式控制超氧化物的局部生成来负调节 LR 发育。这些发现为 NADPH 氧化酶介导的拟南芥 LR 分支调节机制提供了新的见解。
NADPH oxidase AtrbohD an d AtrbohF negatively modulate lateral root development by changing the peroxidase activity and increasing the local generation of superoxide in primary roots of Arabidopsis in an auxin-independent manner.NADPH oxidase subunits AtrbohD and AtrbohF play pivotal roles in regulating growth, development and stress responses in Arabidopsis. However, whether they modulate lateral root (LR) formation has not yet been addressed, and the detailed mechanisms underlying the process remain unanswered. Here, we show that two null double mutants atrbohD1/F1 and atrbohD2/F2, in which both AtrbohD and AtrbohF genes are disrupted, had remarkably higher LR density than wild-type (WT), or the single mutant atrbohD1 and atrbohF1. Compared to WT, the double mutants exhibited early emerged LRs and enhanced density of lateral root primordia (LRP). Unexpectedly, the production of superoxide (O-2 (-)), but not hydrogen peroxide, in the mature area of the primary root containing LRs significantly increased in the double mutants relative to that in WT. Further experiments revealed that the local accumulation of O-2 (-) led to the enhancement of LR density in the double mutants. Moreover, the deficiency of AtrbohD and AtrbohF caused a marked increase in peroxidase activity in the mature root zone, which contributed to the localized accumulation of O-2 (-) and the elevated LR density in the double mutants. Furthermore, the double mutants were not sensitive to exogenous auxin naphthalene acetic acid or auxin transport inhibitor 1-N-naphthylphthalamic acid in terms of LR formation. The auxin response of LRP in vivo in atrbohD1/F1 was also similar to that in WT. Taken together, these results suggest that AtrbohD and AtrbohF negatively modulate LR development by controlling the local generation of superoxide in an auxin-independent manner. These findings provide new insights into the mechanisms of NADPH oxidase-mediated regulation of LR branching in Arabidopsis.