Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.
Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.
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DOI：
10.1016/j.phytochem.2014.07.010
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发表时间：
2015-04
期刊：
影响因子：
3.8
通讯作者：
Ausubel FM
中科院分区：
文献类型：
--
作者：
Mammarella ND;Cheng Z;Fu ZQ;Daudi A;Bolwell GP;Dong X;Ausubel FM
NADPH氧化酶或质外体过氧化物酶产生的ROS在植物的防御反应中起着重要作用。先前研究表明，由于异源菜豆过氧化物酶基因(asFBP1.1)的反义表达，至少两个拟南芥过氧化物酶编码基因PrX33(At3g49110)和PrX34(At3g49120)的表达减弱，导致病原菌攻击后ROS水平降低，对各种细菌和真菌病原体的敏感性增强，以及响应微生物相关分子模式(MAMP)分子flg22和elf26而导致老茧的产生和防御相关基因表达的水平降低。这些数据表明，依赖于过氧化物酶的氧化爆发在模式触发免疫(PTI)的诱导中起着重要作用。然而，本文报道的进一步工作表明，asFBP1.1反义植物在所有与PTI相关的反应中都没有受到损害。例如，在asFPB1.1中，flg22诱导的一些但不是所有flg22基因的表达水平降低，并且在asFPB1.1中，用丁香假单胞菌hrcC突变体或非寄主丁香假单胞菌致病变种渗透后，asFPB1.1中的城市糖沉积类似于野生型。此外，asFPB1.1植株在安装过敏性反应(HR)的能力上没有表现出任何明显的缺陷。另一方面，水杨酸(SA)介导的PR1的激活在asFPB1.1植物中显著减弱。此外，紫丁香疫霉诱导的许多已知依赖SA的基因在asFBP1.1植物中的表达显著减少。与后一个结果一致的是，在asFBP1.1植物中，SA介导反应的关键调节因子NPR1显示总蛋白丰度显著降低，并且未能单体，而单体是蛋白质转运到细胞核中所必需的。
Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus.