Metabolic Integration and Cell Signaling Group, Plant Physiology Section, Department of CAMN, Universitat Jaume I, Avd Vicente Sos Baynat, Castellón 12071, Spain.
Plant Physiol Biochem. 2012 Dec;61:169-79. doi: 10.1016/j.plaphy.2012.10.004. Epub 2012 Oct 13.
Plant resistance against the necrotrophic pathogen Plectosphaerella cucumerina is mediated by a combination of several hormonal-controlled signalling pathways. The priming agent β-aminobutyric acid (BABA) is able to induce effective resistance against this pathogen by stimulating callose-rich cell wall depositions. In the present research it is demonstrated that BABA-Induced Resistance (BABA-IR) against P. cucumerina in Arabidopsis has additional components such as the induction of defences mediated by indolic derivatives. Chromatographic approach for the detection and characterization of metabolites enhanced by BABA compared with water-treated plants only when the challenge is present has been developed. The metabolites matching this criteria are considered to be primed by BABA. The analytic procedure is based on the combination of liquid chromatography (LC) with a triple quadrupole (TQD) detector in a precursor ion scanning mode. Using this analytical system a signal in negative electro-spray mode of 160 m/z is primed by BABA in infected plants. A subsequent exact mass analysis in a quadrupole time-of-flight mass spectrometer demonstrated that this ion was the indole-derivative metabolite indole-3-carboxylic acid (I3CA). The identity of indole-3-carboxilic acid was definitively confirmed by comparing its retention time and fragmentation spectra with a commercial standard. Quantification of I3CA in primed plants showed that this indolic metabolite is specifically primed by BABA upon P. cucumerina infection, while other indolic compounds such as IAA and camalexin are not. Taking together these observations with the known role of callose in priming against this pathogen, suggests that priming is not a single mechanism but rather a multicomponent defence.
植物对坏死性病原菌 Pleochrosphaerella cucumerina 的抗性是由几种激素控制的信号通路共同介导的。引发剂 β-氨基丁酸（BABA）通过刺激富含几丁质的细胞壁沉积，能够诱导对这种病原体的有效抗性。在本研究中，证明了 BABA 诱导的拟南芥对 P. cucumerina 的抗性（BABA-IR）具有其他成分，例如吲哚衍生物介导的防御反应的诱导。开发了一种用于检测和表征 BABA 增强的代谢物的色谱方法，与仅用水处理的植物相比，只有在存在挑战时，BABA 才会增强这些代谢物。符合此标准的代谢物被认为是由 BABA 引发的。分析程序基于液相色谱（LC）与三重四极杆（TQD）检测器在正离子扫描模式下的组合。使用该分析系统，在负电喷雾模式下，160 m/z 的信号在感染植物中被 BABA 引发。在四极杆飞行时间质谱仪中进行的精确质量分析表明，该离子是吲哚衍生代谢物吲哚-3-羧酸（I3CA）。通过比较其保留时间和碎片图谱与商业标准品，吲哚-3-羧酸的身份得到了明确确认。在引发的植物中定量 I3CA 表明，这种吲哚代谢物是由 BABA 特异性引发的，而其他吲哚化合物，如 IAA 和 camalexin，则不是。将这些观察结果与已知的几丁质在对抗这种病原体的引发作用结合起来，表明引发不是单一机制，而是一种多组分防御。
