Defense Priming in Nicotiana tabacum Accelerates and Amplifies ‘New’ C/N Fluxes in Key Amino Acid Biosynthetic Pathways
Year: 2020
Type: article
Abstract: In the struggle to survive herbivory by leaf-feeding insects, plants employ multiple strategies to defend themselves. One mechanism by which plants increase resistance is by intensifying their responsiveness in the production of certain defense agents to create a rapid response. Known as defense priming, this action can accelerate and amplify responses of metabolic pathways, providing plants with long-lasting resistance, especially when faced with waves of attack. In the work presented, short-lived radiotracers of carbon administered as 11CO2 and nitrogen administered as 13NH3 were applied in Nicotiana tabacum, to examine the temporal changes in ‘new’ C/N utilization in the biosynthesis of key amino acids (AAs). Responses were induced by using topical application of the defense hormone jasmonic acid (JA). After a single treatment, metabolic partitioning of recently fixed carbon (designated ‘new’ carbon and reflected as 11C) increased through the shikimate pathway, giving rise to tyrosine, phenylalanine and tryptophan. Amplification in ‘new’ carbon fluxes preceded changes in the endogenous (12C) pools of these AAs. Testing after serial JA treatments revealed that fluxes of ‘new’ carbon were accelerated, amplified and sustained over time at this higher rate, suggesting a priming effect. Similar results were observed with recently assimilated nitrogen (designated ‘new’ nitrogen reflected as 13N) with its partitioning into serine, glycine and glutamine, which play important roles supporting the shikimate pathway and downstream secondary metabolism. Finally, X-ray fluorescence imaging revealed that levels of the element Mn, an important co-factor for enzyme regulation in the shikimate pathway, increased within JA treated tissues, suggesting a link between plant metal ion regulation and C/N metabolic priming.
Source: Plants
Language: English
Subfield: Insect Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $1,690
Awards: DEVELOPMENT OF SYNCHROTRON X-RAY MICRO-SPECTROSCOPIC TECHNIQUES AND APPLICATION TO PROBLEMS IN LOW TEMPERATURE GEOCHEMISTRY, G1126863173, G1285306620, G1286251239, G132563423, G1572106353, SYNCHROTRON X-RAY MICROPROBE AND MICROSPECTROSCOPY RESEARCH IN LOW TEMPERATURE GEOCHEMISTRY, G1847291448, G1867732070, G222768804, G241279073, G3243759740, G3262563802, G338944111, G357145406, G3897559065, G4768711226, G498139845, G5019921669, G5292656900, G549834383, G5648016710, G5765906131, G6965541988, G719843099, G7463374569, G8435008881, G8507651203, G969889393
OpenAlex ID: W3040017597