鉴定拟南芥磷脂酰肌醇 4-激酶β双突变体中水杨酸非依赖的反应。
Identification of salicylic acid-independent responses in an Arabidopsis phosphatidylinositol 4-kinase beta double mutant.
机构信息
Institute of Experimental Botany, The Czech Academy of Sciences, Prague, Czech Republic.
Université Paris-Est, UPEC, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Créteil, France.
出版信息
Ann Bot. 2020 Apr 25;125(5):775-784. doi: 10.1093/aob/mcz112.
BACKGROUND AND AIMS
We have recently shown that an Arabidopsis thaliana double mutant of type III phosphatidylinositol-4-kinases (PI4Ks), pi4kβ1β2, constitutively accumulated a high level of salicylic acid (SA). By crossing this pi4kβ1β2 double mutant with mutants impaired in SA synthesis (such as sid2 impaired in isochorismate synthase) or transduction, we demonstrated that the high SA level was responsible for the dwarfism phenotype of the double mutant. Here we aimed to distinguish between the SA-dependent and SA-independent effects triggered by the deficiency in PI4Kβ1 and PI4Kβ2.
METHODS
To achieve this we used the sid2pi4kβ1β2 triple mutant. High-throughput analyses of phytohormones were performed on this mutant together with pi4kβ1β2 and sid2 mutants and wild-type plants. Responses to pathogens, namely Hyaloperonospora arabidopsidis, Pseudomonas syringae and Botrytis cinerea, and also to the non-host fungus Blumeria graminis, were also determined. Callose accumulation was monitored in response to flagellin.
KEY RESULTS
We show here the prominent role of high SA levels in influencing the concentration of many other tested phytohormones, including abscisic acid and its derivatives, the aspartate-conjugated form of indole-3-acetic acid and some cytokinins such as cis-zeatin. We show that the increased resistance of pi4kβ1β2 plants to the host pathogens H. arabidopsidis, P. syringae pv. tomato DC3000 and Bothrytis cinerea is dependent on accumulation of high SA levels. In contrast, accumulation of callose in pi4kβ1β2 after flagellin treatment was independent of SA. Concerning the response to Blumeria graminis, both callose accumulation and fungal penetration were enhanced in the pi4kβ1β2 double mutant compared to wild-type plants. Both of these processes occurred in an SA-independent manner.
CONCLUSIONS
Our data extensively illustrate the influence of SA on other phytohormone levels. The sid2pi4kβ1β2 triple mutant revealed the role of PI4Kβ1/β2 per se, thus showing the importance of these enzymes in plant defence responses.
背景和目的
我们最近发现拟南芥的 III 型磷酸肌醇 4-激酶（PI4Ks）双突变体 pi4kβ1β2 持续积累高水平的水杨酸（SA）。通过将这个 pi4kβ1β2 双突变体与 SA 合成缺陷（如异分支酸合酶缺陷的 sid2）或转导缺陷的突变体杂交，我们证明高水平的 SA 是双突变体矮化表型的原因。在这里，我们旨在区分 PI4Kβ1 和 PI4Kβ2 缺乏引起的依赖于 SA 和不依赖于 SA 的影响。
方法
为了实现这一目标，我们使用了 sid2pi4kβ1β2 三突变体。对该突变体与 pi4kβ1β2 和 sid2 突变体和野生型植物一起进行了植物激素的高通量分析。还测定了对病原体（即 Hyaloperonospora arabidopsidis、Pseudomonas syringae 和 Botrytis cinerea）以及非宿主真菌 Blumeria graminis 的反应，还监测了 flagellin 诱导的几丁质积累。
主要结果
我们在这里展示了高水平 SA 在影响许多其他测试植物激素的浓度方面的突出作用，包括脱落酸及其衍生物、天冬氨酸结合形式的吲哚-3-乙酸和一些细胞分裂素，如顺式玉米素。我们表明，pi4kβ1β2 植物对宿主病原体 H. arabidopsidis、P. syringae pv. tomato DC3000 和 Botrytis cinerea 的抗性增加依赖于高水平 SA 的积累。相比之下，pi4kβ1β2 在 flagellin 处理后积累的几丁质与 SA 无关。关于对 Blumeria graminis 的反应，与野生型植物相比，pi4kβ1β2 双突变体中的几丁质积累和真菌穿透增强。这两个过程都是在不依赖 SA 的情况下发生的。
结论
我们的数据广泛说明了 SA 对其他植物激素水平的影响。sid2pi4kβ1β2 三突变体揭示了 PI4Kβ1/β2 的自身作用，从而显示了这些酶在植物防御反应中的重要性。
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