Metabolomics in Plant Priming Research: The Way Forward?

Fidele Tugizimana,Lizelle Piater,Msizi Mhlongo,Ian Dubery

doi:10.3390/ijms19061759

Fidele Tugizimana, Lizelle Piater + Show 2 more

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https://doi.org/10.3390/ijms19061759

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Abstract

A new era of plant biochemistry at the systems level is emerging, providing detailed descriptions of biochemical phenomena at the cellular and organismal level. This new era is marked by the advent of metabolomics—the qualitative and quantitative investigation of the entire metabolome (in a dynamic equilibrium) of a biological system. This field has developed as an indispensable methodological approach to study cellular biochemistry at a global level. For protection and survival in a constantly-changing environment, plants rely on a complex and multi-layered innate immune system. This involves surveillance of ‘self’ and ‘non-self,’ molecule-based systemic signalling and metabolic adaptations involving primary and secondary metabolites as well as epigenetic modulation mechanisms. Establishment of a pre-conditioned or primed state can sensitise or enhance aspects of innate immunity for faster and stronger responses. Comprehensive elucidation of the molecular and biochemical processes associated with the phenotypic defence state is vital for a better understanding of the molecular mechanisms that define the metabolism of plant–pathogen interactions. Such insights are essential for translational research and applications. Thus, this review highlights the prospects of metabolomics and addresses current challenges that hinder the realisation of the full potential of the field. Such limitations include partial coverage of the metabolome and maximising the value of metabolomics data (extraction of information and interpretation). Furthermore, the review points out key features that characterise both the plant innate immune system and enhancement of the latter, thus underlining insights from metabolomic studies in plant priming. Future perspectives in this inspiring area are included, with the aim of stimulating further studies leading to a better understanding of plant immunity at the metabolome level.

Highlights

Multi-Layered Molecular and Cellular Networks Ensure Effective Adaptation to Changing EnvironmentsEvolution dictates that living systems constantly adapt to ever-changing environments in a context-dependent manner
Elucidating host receptors and regulatory mechanisms that determine certain responses, unravelling biochemical processes in specific phytopathosystems, elucidating the environmental influences on diverse phyllosphere and rhizosphere interactions with microorganisms, and illuminating epigenetic regulatory mechanisms that result in passing on defensive traits to the progeny are some of the topics that still need to be fully explored
We give a brief overview of the current mechanistic understanding of the plant innate immune system related to priming

Summary

Introduction

Evolution dictates that living systems constantly adapt to ever-changing environments in a context-dependent manner. Most of the efforts in characterising and defining the biochemical changes related to priming processes have been driven by targeted approaches These methodologies have played a vital role in elucidating the main elements of priming that includes enhanced perception systems, dormant signal transduction enzymes, chromatin modification and transcription factors [19,23,29,30,31], there are still gaps in holistically understanding the dynamism and complexity of molecular mechanisms involved in the entire priming event, considering the complexity of multi-layered biological information networks. Stereochemistries), a wide range of metabolite levels and the inherent bio-complexity of living systems (biological cycles, organismal and cellular compartmentalisation) [40,45,60,61] These challenges point to the bottlenecks that have limited (untargeted) metabolomics so far (Figure 2), making the holistic coverage of the whole metabolome currently unrealisable and subsequently impacting the biological insights generated. Elucidating host receptors and regulatory mechanisms that determine certain responses, unravelling biochemical processes in specific phytopathosystems, elucidating the environmental influences on diverse phyllosphere and rhizosphere interactions with microorganisms, and illuminating epigenetic regulatory mechanisms that result in passing on defensive traits to the progeny are some of the topics that still need to be fully explored

Plant Priming

Concluding Remarks and Perspectives