Laboratory of Molecular and Cell Biology, Institute of Biology, University of Neuchâtel, Neuchâtel, 2000, Switzerland.
Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, 2000, Switzerland.
Planta. 2017 Oct;246(4):791-796. doi: 10.1007/s00425-017-2751-3. Epub 2017 Aug 1.
Endogenous levels of β-aminobutyric acid (BABA) increase after the molecular recognition of pathogen presence. BABA is accumulated differently during resistance or susceptibility to disease. The priming molecule β-aminobutyric acid has been recently shown to be a natural product of plants, and this has provided significance to the previous discovery of a perception mechanism in Arabidopsis. BABA levels were found to increase after abiotic stress or infection with virulent pathogens, but the role of endogenous BABA in defence has remained to be established. To investigate the biological significance of endogenous BABA variations during plant-pathogen interactions, we investigated how infections with virulent, avirulent (AvrRpt2), and non-pathogenic (hrpA) strains of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), as well as treatment with defence elicitors (Flg22 and AtPep2), affect the accumulation of BABA in Arabidopsis plants. We found that BABA levels increased more rapidly during resistance than susceptibility to Pst DC3000. In addition, BABA was accumulated during PAMP-triggered immunity (PTI) after infection with the non-pathogenic Pst DC3000 hrpA mutant, or treatment with elicitors. Importantly, treatment with Flg22 induced BABA rise in Columbia-0 plants but not in Wassilewskija-0 plants, which naturally possess a non-functional flagellin receptor. These results indicate that BABA levels are controlled by the plant's immune system, thus advancing the understanding of the biological role of plant produced BABA.
内源性β-氨基丁酸（BABA）水平在分子识别病原体存在后增加。BABA 在对疾病的抗性或易感性方面的积累方式不同。最近，作为植物天然产物的BABA 前体分子已被证明存在，这为先前在拟南芥中发现的感知机制提供了重要依据。发现非生物胁迫或感染毒性病原体后，BABA 水平会升高，但内源性 BABA 在防御中的作用仍有待确定。为了研究植物-病原体相互作用过程中内源性 BABA 变化的生物学意义，我们研究了感染毒性、非毒性（AvrRpt2）和非致病性（hrpA）的丁香假单胞菌 pv.番茄 DC3000（Pst DC3000）菌株，以及防御激发子（Flg22 和 AtPep2）处理如何影响拟南芥中 BABA 的积累。结果发现，与对 Pst DC3000 的易感性相比，抗性过程中 BABA 水平增加得更快。此外，非致病性 Pst DC3000 hrpA 突变体感染或用激发子处理后，也会引发 PTI 中 BABA 的积累。重要的是，Flg22 处理可诱导哥伦比亚-0 植株中 BABA 的升高，但不能诱导瓦西里耶夫斯基-0 植株中 BABA 的升高，因为后者天然缺乏功能失常的鞭毛蛋白受体。这些结果表明，BABA 水平受植物免疫系统控制，从而加深了对植物产生 BABA 的生物学作用的理解。
