Root-expressed maize lipoxygenase 3 negatively regulates induced systemic resistance to Colletotrichum graminicola in shoots.
Root-expressed maize lipoxygenase 3 negatively regulates induced systemic resistance to Colletotrichum graminicola in shoots.
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DOI：
10.3389/fpls.2013.00510
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发表时间：
2013
影响因子：
5.6
通讯作者：
Kolomiets MV
中科院分区：
文献类型：
--
作者：
Constantino NN;Mastouri F;Damarwinasis R;Borrego EJ;Moran-Diez ME;Kenerley CM;Gao X;Kolomiets MV
我们之前已经报道，玉米根系表达的9-脂氧合酶(9-LOX)基因ZmLOX3的中断会导致玉米对不同的叶和茎病原菌的抗性显著增加。尽管这些发现具有明显的经济意义，但这种耐药性增加背后的机制仍然难以捉摸。在本研究中，我们发现LOX3-4突变体的抗性增加是由于诱导的系统抗性(ISR)信号的结构性激活。结果表明，ZmLOX3对炭疽病病原菌Colletotrichum graminicola的响应在叶片中缺乏表达，但在根中有结构性表达，从而提出了我们的假说：LOX3-4突变体的根是叶片抗性增强的来源。支持这一假设的是，用LOX3-4突变体的木质部汁液处理野生型植物(WT)诱导的对稻瘟病菌的抗性水平与LOX3-4突变体中观察到的水平相当。此外，用从WT植物采集的汁液处理突变体，部分恢复了对稻瘟病菌的敏感性。与WT相比，LOX3-4突变体在感染后表现出启动的防御反应，包括更早和更多地诱导与防御相关的PAL和GST基因。LOX3-4突变体不仅有较高的十八烷类途径基因表达，而且对稻瘟病菌的侵染或甲氧西林的处理有更早的反应和更多的H_2O_2积累。这些发现表明，LOX3-4突变体表现出结构性的ISR样信号。支持这一观点的是，绿色木霉GV29-8菌株的根部定殖在WT中诱导了与突变体液处理相同的抗病水平，而在LOX3-4突变体中没有额外的抗性效应。在水培根中，T.virens GV29强而迅速地抑制了ZmLOX3的表达，而ISR诱导缺陷的T.virensΔ突变体不能抑制ZmLOX3的表达，从而提供了SM1至少部分通过抑制宿主ZmLOX3基因在ISR中发挥作用的遗传证据。这项研究和在此产生的基因工具将使今后能够识别调控有益土壤微生物诱导对地上侵袭者的抗性的信号。
We have previously reported that disruption of a maize root-expressed 9-lipoxygenase (9-LOX) gene, ZmLOX3, results in dramatic increase in resistance to diverse leaf and stalk pathogens. Despite evident economic significance of these findings, the mechanism behind this increased resistance remained elusive. In this study, we found that increased resistance of the lox3-4 mutants is due to constitutive activation of induced systemic resistance (ISR) signaling. We showed that ZmLOX3 lacked expression in leaves in response to anthracnose leaf blight pathogen Colletotrichum graminicola, but was expressed constitutively in the roots, thus, prompting our hypothesis: the roots of lox3-4 mutants are the source of increased resistance in leaves. Supporting this hypothesis, treatment of wild-type plants (WT) with xylem sap of lox3-4 mutant induced resistance to C. graminicola to the levels comparable to those observed in lox3-4 mutant. Moreover, treating mutants with the sap collected from WT plants partially restored the susceptibility to C. graminicola. lox3-4 mutants showed primed defense responses upon infection, which included earlier and greater induction of defense-related PAL and GST genes compared to WT. In addition to the greater expression of the octadecanoid pathway genes, lox3-4 mutant responded earlier and with a greater accumulation of H2O2 in response to C. graminicola infection or treatment with alamethicin. These findings suggest that lox3-4 mutants display constitutive ISR-like signaling. In support of this idea, root colonization by Trichoderma virens strain GV29-8 induced the same level of disease resistance in WT as the treatment with the mutant sap, but had no additional resistance effect in lox3-4 mutant. While treatment with T. virens GV29 strongly and rapidly suppressed ZmLOX3 expression in hydroponically grown WT roots, T. virens Δsml mutant, which is deficient in ISR induction, was unable to suppress expression of ZmLOX3, thus, providing genetic evidence that SM1 function in ISR, at least in part, by suppressing host ZmLOX3 gene. This study and the genetic tools generated herein will allow the identification of the signals regulating the induction of resistance to aboveground attackers by beneficial soil microorganisms in the future.
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影响因子：
64.8
作者：
Delledonne, M;Xia, YJ;Lamb, C
通讯作者：
Lamb, C
影响因子：
9.4
作者：
Baltruschat, Helmut;Fodor, Jozsef;Skoczowski, Andrzej
通讯作者：
Skoczowski, Andrzej
影响因子：
6.7
作者：
Huang K;Czymmek KJ;Caplan JL;Sweigard JA;Donofrio NM
通讯作者：
Donofrio NM
影响因子：
11.6
作者：
Nalam, Vamsi J.;Keeretaweep, Jantana;Shah, Jyoti
通讯作者：
Shah, Jyoti
影响因子：
3.5
作者：
Mastouri, Fatemeh;Bjoerkman, Thomas;Harman, Gary E.
通讯作者：
Harman, Gary E.