Rapid metabolic profiling of Nicotiana tabacum defence responses against Phytophthora nicotianae using direct infrared laser desorption ionization mass spectrometry and principal component analysis

Abstract

BackgroundSuccessful defence of tobacco plants against attack from the oomycete Phytophthora nicotianae includes a type of local programmed cell death called the hypersensitive response. Complex and not completely understood signaling processes are required to mediate the development of this defence in the infected tissue. Here, we demonstrate that different families of metabolites can be monitored in small pieces of infected, mechanically-stressed, and healthy tobacco leaves using direct infrared laser desorption ionization orthogonal time-of-flight mass spectrometry. The defence response was monitored for 1 - 9 hours post infection.ResultsInfrared laser desorption ionization orthogonal time-of-flight mass spectrometry allows rapid and simultaneous detection in both negative and positive ion mode of a wide range of naturally occurring primary and secondary metabolites. An unsupervised principal component analysis was employed to identify correlations between changes in metabolite expression (obtained at different times and sample treatment conditions) and the overall defence response.A one-dimensional projection of the principal components 1 and 2 obtained from positive ion mode spectra was used to generate a Biological Response Index (BRI). The BRI obtained for each sample treatment was compared with the number of dead cells found in the respective tissue. The high correlation between these two values suggested that the BRI provides a rapid assessment of the plant response against the pathogen infection. Evaluation of the loading plots of the principal components (1 and 2) reveals a correlation among three metabolic cascades and the defence response generated in infected leaves. Analysis of selected phytohormones by liquid chromatography electrospray ionization mass spectrometry verified our findings.ConclusionThe described methodology allows for rapid assessment of infection-specific changes in the plant metabolism, in particular of phenolics, alkaloids, oxylipins, and carbohydrates. Moreover, potential novel biomarkers can be detected and used to predict the quality of plant infections.

Pipecolic acid enhances resistance to bacterial infection and primes salicylic acid and nicotine accumulation in tobacco

“…43,44 By contrast, infection with the oomycete pathogen Phytophtora nicotianae resulted in decreased nicotine levels. 45 Whether a plant protective function of nicotine toward microbial pathogen infection exists is yet indeterminate to our knowledge, although nicotine has been demonstrated to have in vitro antimicrobial activity to several human-pathogenic fungi and bacteria. 46 Interestingly, our results show that, similar to camalexin accumulation in Arabidopsis, 17 the P. syringae-induced production of nicotine in tobacco is strongly potentiated by Pip (Fig.…”

The Nicotiana attenuata GLA1 lipase controls the accumulation of Phytophthora parasitica‐induced oxylipins and defensive secondary metabolites

“…Consistent with gene expression studies, metabolic profiling of tobacco ( N. tabacum ) plants infected with P. parasitica (Ibanez et al . ) and of potato plants infected with P. infestans (Henriquez et al . ) show a strong accumulation of secondary metabolites produced by these three biosynthesis pathways.…”

Metabolite profiling of Mexican lime (Citrus aurantifolia) leaves during the progression of witches’ broom disease

“…Ibanez et al (2010) showed that PCA is a useful technique for diagnosis of healthy Nicotiana tabacum from P. nicotianae-infected plant.…”