A pqr2 mutant encodes a defective polyamine transporter and is negatively affected by ABA for paraquat resistance in Arabidopsis thaliana
A pqr2 mutant encodes a defective polyamine transporter and is negatively affected by ABA for paraquat resistance in Arabidopsis thaliana
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DOI：
10.1007/s10265-016-0819-y
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发表时间：
2016-09-01
影响因子：
2.8
通讯作者：
Feng, Shengqiu
中科院分区：
文献类型：
--
作者：
Dong, Shuchao;Hu, Huizhen;Feng, Shengqiu
尽管在植物中已经报道了百草枯抗性突变体，但本研究发现了一种新的A。thaliana突变体（pqr 2）的抗2 μ M百草枯活性。pqr 2突变体在AT 1G 31830/PAR 1/PQR 2的外显子上存在终止突变，编码多胺摄取转运蛋白AtPUT 2/PAR 1/PQR 2。在百草枯处理下，PQR 2突变体可以显著降低pqr 2植株中超氧自由基的积累和细胞死亡。此外，与野生型相比，pqr 2突变体表现出对腐胺（一种经典的多胺化合物）的耐受性大大降低，这证实了PQR 2编码缺陷型多胺转运蛋白。在阿坝和百草枯共同处理下，pqr 2突变体和野生型均表现出致死性，而野生型在阿坝合成抑制剂Na 2 WO 4的高剂量处理下仍能保持对百草枯的抗性。基因表达分析表明，阿坝信号广泛调控百草枯响应基因在野生型和pqr 2突变体中的独特性。因此，本研究首次报道了阿坝对苜蓿百草枯抗性的负面影响。thaliana，提供了深入了解阿坝信号参与百草枯诱导的植物氧化应激反应。
Despite the paraquat-resistant mutants that have been reported in plants, this study identified a novel A. thaliana mutant (pqr2) from an XVE inducible activation library based on its resistance to 2 mu M paraquat. The pqr2 mutant exhibited a termination mutation in the exon of AT1G31830/PAR1/PQR2, encoded a polyamine uptake transporter AtPUT2/PAR1/PQR2. The PQR2 mutation could largely reduce superoxide accumulation and cell death in the pqr2 plants under paraquat treatment. Moreover, compared with wild type, the pqr2 mutant exhibited much reduced tolerance to putrescine, a classic polyamine compound, which confirmed that PQR2 encoded a defective polyamine transporter. Notably, co-treated with ABA and paraquat, both pqr2 mutant and wild type exhibited a lethal phenotype from seed germination, but the wild type like pqr2 mutant, could remain paraquat-resistance while co-treated with high dosage of Na2WO4, an ABA synthesis inhibitor. Gene expression analysis suggested that ABA signaling should widely regulate paraquat-responsive genes distinctively in wild type and pqr2 mutant. Hence, this study has for the first time reported about ABA negative effect on paraquat-resistance in A. thaliana, providing insight into the ABA signaling involved in the oxidative stress responses induced by paraquat in plants.