Research Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg, 2006, South Africa.
Planta. 2024 May 24;260(1):8. doi: 10.1007/s00425-024-04435-w.
A gene-to-metabolite approach afforded new insights regarding defence mechanisms in oat plants that can be incorporated into plant breeding programmes for the selection of markers and genes related to disease resistance. Monitoring metabolite levels and changes therein can complement and corroborate transcriptome (mRNA) data on plant-pathogen interactions, thus revealing mechanisms involved in pathogen attack and host defence. A multi-omics approach thus adds new layers of information such as identifying metabolites with antimicrobial properties, elucidating metabolomic profiles of infected and non-infected plants, and reveals pathogenic requirements for infection and colonisation. In this study, two oat cultivars (Dunnart and SWK001) were inoculated with Pseudomonas syringae pathovars, pathogenic and non-pathogenic on oat. Following inoculation, metabolites were extracted with methanol from leaf tissues at 2, 4 and 6 days post-infection and analysed by multiple reaction monitoring (MRM) on a triple quadrupole mass spectrometer system. Relatedly, mRNA was isolated at the same time points, and the cDNA analysed by quantitative PCR (RT-qPCR) for expression levels of selected gene transcripts associated with avenanthramide (Avn) biosynthesis. The targeted amino acids, hydroxycinnamic acids and Avns were successfully quantified. Distinct cultivar-specific differences in the metabolite responses were observed in response to pathogenic and non-pathogenic strains. Trends in aromatic amino acids and hydroxycinnamic acids seem to indicate stronger activation and flux through these pathways in Dunnart as compared to SWK001. A positive correlation between hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT) gene expression and the abundance of Avn A in both cultivars was documented. However, transcript profiling of selected genes involved in Avn synthesis did not reveal a clear pattern to distinguish between the tolerant and susceptible cultivars.
一种从基因到代谢物的方法为燕麦植物的防御机制提供了新的见解，这些机制可以被纳入植物育种计划，以选择与抗病性相关的标记和基因。监测代谢物水平及其变化可以补充和证实植物-病原体相互作用的转录组（mRNA）数据，从而揭示参与病原体攻击和宿主防御的机制。因此，多组学方法增加了新的信息层，例如鉴定具有抗菌特性的代谢物、阐明感染和未感染植物的代谢组图谱，以及揭示感染和定植的致病性要求。在这项研究中，两个燕麦品种（Dunnart 和 SWK001）用丁香假单胞菌的不同菌株（对燕麦有致病性和非致病性的菌株）接种。接种后，在感染后 2、4 和 6 天从叶片组织中用甲醇提取代谢物，并在三重四极杆质谱系统上通过多重反应监测（MRM）进行分析。同时分离 mRNA，并通过定量 PCR（RT-qPCR）分析相同时间点的 cDNA，以分析与燕麦酰胺（Avn）生物合成相关的选定基因转录本的表达水平。目标氨基酸、羟基肉桂酸和 Avn 成功定量。对致病性和非致病性菌株的反应，观察到不同品种特有的代谢物反应差异。芳香族氨基酸和羟基肉桂酸的趋势似乎表明，与 SWK001 相比，Dunnart 中这些途径的激活和通量更强。在两个品种中，羟基肉桂酰辅酶 A：羟基苯丙氨酸 N-羟基肉桂酰转移酶（HHT）基因表达与 Avn A 丰度之间存在正相关。然而，参与 Avn 合成的选定基因的转录谱并没有揭示出一种清晰的模式来区分耐病和易感品种。
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