Both the stimulation and inhibition of root hair growth induced by extracellular nucleotides in Arabidopsis are mediated by nitric oxide and reactive oxygen species
Both the stimulation and inhibition of root hair growth induced by extracellular nucleotides in Arabidopsis are mediated by nitric oxide and reactive oxygen species
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DOI：
10.1007/s11103-010-9683-7
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发表时间：
2010-11-01
影响因子：
5.1
通讯作者：
Roux, Stanley J.
中科院分区：
文献类型：
--
作者：
Clark, Greg;Wu, Michael;Roux, Stanley J.
根毛在生长过程中分泌ATP，细胞外ATP和ADP可以触发调节植物细胞生长的信号通路。在几种植物组织中，细胞外核苷酸的水平部分地受到外腺苷三磷酸双磷酸酶（外-NTPDases）的限制，并且这些组织的生长受到它们的外腺苷三磷酸双磷酸酶表达水平的强烈影响。在拟南芥中，通过RNAi化学抑制外腺苷三磷酸双磷酸酶活性和抑制两种外腺苷三磷酸双磷酸酶的表达都导致根毛生长的抑制。根据剂量-反应曲线测定，不同浓度的难水解核苷酸，ATP γ S和ADP β S，可以在不到一小时内刺激（7.5-25 μ M）或抑制（150 μ M）根毛的生长速率。等量的AMPS作为对照，对根毛生长没有影响。根毛的nia 1 nia 2突变体，这是抑制一氧化氮（NO）的生产，和atrbohD/F突变体，这是抑制过氧化氢的生产，没有显示生长反应，应用核苷酸，表明这些核苷酸在野生型植物诱导的生长变化可能是通过NO和过氧化氢信号转导。与此解释相一致，不同浓度的ATP γ S处理根毛诱导不同的积累NO和H2 O2在根毛尖。两种哺乳动物嘌呤受体拮抗剂也阻断了细胞外核苷酸诱导的生长反应，表明它们是由基于受体的机制启动的。
Root hairs secrete ATP as they grow, and extracellular ATP and ADP can trigger signaling pathways that regulate plant cell growth. In several plant tissues the level of extracellular nucleotides is limited in part by ectoapyrases (ecto-NTPDases), and the growth of these tissues is strongly influenced by their level of ectoapyrase expression. Both chemical inhibition of ectoapyrase activity and suppression of the expression of two ectoapyrase enzymes by RNAi in Arabidopsis resulted in inhibition of root hair growth. As assayed by a dose-response curve, different concentrations of the poorly hydrolysable nucleotides, ATP gamma S and ADP beta S, could either stimulate (at 7.5-25 mu M) or inhibit (at a parts per thousand yen 150 mu M) the growth rate of root hairs in less than an hour. Equal amounts of AMPS, used as a control, had no effect on root hair growth. Root hairs of nia1nia2 mutants, which are suppressed in nitric oxide (NO) production, and of atrbohD/F mutants, which are suppressed in the production of H2O2, did not show growth responses to applied nucleotides, indicating that the growth changes induced by these nucleotides in wild-type plants were likely transduced via NO and H2O2 signals. Consistent with this interpretation, treatment of root hairs with different concentrations of ATP gamma S induced different accumulations of NO and H2O2 in root hair tips. Two mammalian purinoceptor antagonists also blocked the growth responses induced by extracellular nucleotides, suggesting that they were initiated by a receptor-based mechanism.