Institute of Biology, Laboratory of Molecular and Cell Biology, University of Neuchâtel, Neuchâtel, Switzerland.
Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland.
Plant Biol (Stuttg). 2019 Mar;21(2):318-325. doi: 10.1111/plb.12940. Epub 2018 Dec 10.
We recently discovered that β-aminobutyric acid (BABA), a molecule known for its ability to prime defences in plants, is a natural plant metabolite. However, the role played by endogenous BABA in plants is currently unknown. In this study we investigated the systemic accumulation of BABA during pathogen infection, levels of BABA during plant growth and development and analysed mutants possibly involved in BABA transport or regulation. BABA was quantified by LC-MS using an improved method adapted from a previously published protocol. Systemic accumulation of BABA was determined by analysing non-infected leaves and roots after localised infections with Plectosphaerella cucumerina or Pseudomonas syringae pv. tomato (Pst) DC3000 avrRpt2. The levels of BABA were also quantified in different plant tissues and organs during normal plant growth, and in leaves during senescence. Mutants affecting amino acid transport (aap6, aap3, prot1 and gat1), γ-aminobutyric acid levels (pop2) and senescence/defence (cpr5-2) were analysed. BABA was found to accumulate only locally after bacterial or fungal infection, with no detectable increase in non-infected systemic plant parts. In leaves, BABA content increased during natural and induced senescence. Reproductive organs had the highest levels of BABA, and the mutant cpr5-2 produced constitutively high levels of BABA. Synthetic BABA is highly mobile in the receiving plant, whereas endogenous BABA appears to be produced and accumulated locally in a tissue-specific way. We discuss a possible role for BABA in age-related resistance and propose a comprehensive model for endogenous and synthetic BABA.
我们最近发现，β-氨基丁酸（BABA），一种已知能够在植物中引发防御机制的分子，是一种天然的植物代谢物。然而，内源性 BABA 在植物中的作用目前尚不清楚。在这项研究中，我们研究了病原体感染过程中 BABA 的系统积累、植物生长发育过程中的 BABA 水平以及分析可能参与 BABA 运输或调节的突变体。BABA 通过 LC-MS 用从先前发表的方案改编的改进方法进行定量。通过分析局部感染 Plectosphaerella cucumerina 或 Pseudomonas syringae pv. tomato (Pst) DC3000 avrRpt2 后非感染叶片和根系来确定 BABA 的系统积累。还在正常植物生长过程中以及叶片衰老过程中量化了不同植物组织和器官中的 BABA 水平。分析了影响氨基酸运输的突变体（aap6、aap3、prot1 和 gat1）、γ-氨基丁酸水平（pop2）和衰老/防御（cpr5-2）。发现 BABA 仅在细菌或真菌感染后局部积累，在未感染的系统植物部分中没有检测到增加。在叶片中，BABA 含量在自然和诱导衰老过程中增加。生殖器官具有最高水平的 BABA，而突变体 cpr5-2 持续产生高水平的 BABA。合成 BABA 在接受植物中具有很高的移动性，而内源性 BABA 似乎以组织特异性的方式在局部产生和积累。我们讨论了 BABA 在与年龄相关的抗性中的可能作用，并提出了内源性和合成 BABA 的综合模型。
