Gamma-aminobutyric acid enhances tolerance to iron deficiency by stimulating auxin signaling in cucumber (Cucumis sativusL.)
Gamma-aminobutyric acid enhances tolerance to iron deficiency by stimulating auxin signaling in cucumber (Cucumis sativusL.)
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γ-氨基丁酸通过刺激黄瓜 (Cucumis sativusL.) 中的生长素信号传导增强对缺铁的耐受性
DOI：
10.1016/j.ecoenv.2020.110285
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发表时间：
2020-04-01
影响因子：
6.8
通讯作者：
Piao, Fengzhi
中科院分区：
文献类型：
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作者：
Guo, Zhixin;Du, Nanshan;Piao, Fengzhi
缺铁严重影响作物产量和品质。γ-氨基丁酸(GABA)在植物对各种逆境的响应中起着至关重要的作用。然而，GABA在黄瓜缺铁反应中的作用和可能的机制在很大程度上仍不清楚。在这里，我们发现缺铁提高了黄瓜叶片和根中GABA的水平。为了探讨γ-氨基丁酸在缺铁中的作用，将幼苗置于5种浓度的GABA(0、5、10、20和40 mmoL L-1)下，在缺铁条件下处理7d。结果表明，20 mM GABA对缺铁应激的缓解效果最好。GABA处理减轻了缺铁引起的黄化和光合作用及生长的抑制，显著提高了地上部和根中铁的含量。外源GABA显著降低了缺铁诱导的营养液pH，提高了铁螯合还原酶(FCR)活性和根系铁吸收相关基因HA1、FRO2和IRT1的转录水平。在缺铁条件下，GABA还增加了生长素(IAA)含量和生长素生物合成(YUC4)、反应(IAA1)和运输(Pin1)基因的表达。此外，外源生长素运输抑制剂1-萘基邻苯二甲酸(NPA)的应用可消除GABA引起的铁缺乏的变化。综上所述，我们发现GABA通过生长素依赖的机制提高了黄瓜对缺铁的耐受性。
Iron deficiency severely affects crop yield and quality. Gamma-aminobutyric acid (GABA) plays a vital role in plant responses to multifarious stresses. However, the role of GABA in Fe deficiency responses and the potential mechanisms remain largely unknown in cucumber. Here, we found that Fe deficiency raised the GABA levels in leaves and roots of cucumber. To probe the role of GABA in Fe deficiency, the seedlings were subjected to five levels of GABA concentrations (0, 5, 10, 20 and 40 mmol L-1) for 7 days under Fe deficiency. The results demonstrated that 20 mM GABA in alleviating the Fe deficiency-induced stress was the most effective. GABA pretreatment reduced the Fe deficiency-induced chlorosis and inhibition of photosynthesis and growth, and significantly enhanced the contents of iron in shoots and roots. Exogenous GABA significantly decreased the pH of nutrient solution and increased ferric-chelate reductase (FCR) activity induced by Fe deficiency and the transcript levels of Fe uptake-related genes HA1, FRO2 and IRT1 in roots. GABA also increased the content of auxin (IAA) and expression of auxin biosynthesis (YUC4), response (IAA1), and transport (PIN1) genes under Fe deficiency. Furthermore, exogenous the auxin transport inhibitor 1-naphthylphthalamic acid (NPA) application abolished the GABA-induced changes in Fe deficiency. In summary, we found that GABA improves tolerance to iron deficiency via an auxin-dependent mechanism in cucumber.