NMR study of age dependent metabolic adjustments in wild type and pp2a-b’γ mutant Arabidopsis thaliana

Abstract

The model plant Arabidopsis thaliana of the cruciferous Brassicaceae family has proven as an excellent tool for genetic modification and understanding of plant metabolic pathways. In this study we set up the methodology of 1H NMR and principal component analysis (PCA) to address metabolic adjustments in Arabidopsis leaves. Wild type, together with a prematurely yellowing mutant deficient in a specific protein phosphatase 2A regulatory subunit PP2A-B’γ and a pp2a-b’γ 35S:PP2A-B’γ complementation line were analyzed at 4 and 6 weeks of age to reveal metabolic differences between vegetative and maturation phases of rosette growth. A PCA model revealed similar age-dependent metabolic adjustments in all genotypes. The contents of choline, sinapoyl malate, alanine and glutamine were high in four-week-old Arabidopsis plants and less abundant in six-week-old plants. Moreover, γ-aminobutyric acid (GABA) was observed only in four-week-old plants, whereas six-week-old plants were devoid of this metabolic compound. In contrast, the contents of fumaric acid, glucose and fructose became elevated at six weeks of age. β-Sitosterol was observed to be more abundant in 4 weeks old Arabidopsis rosettes, while α-linolenic and linoleic acids indicated higher content in 6 weeks old Arabidopsis rosettes. Total chlorophyll (Chl) content was higher in 4 weeks old Arabidopsis, whereas high content of Chl b was observed in 6 weeks old plants. We conclude that NMR based metabolomics analysis is a potential method for identification of age-dependent metabolites in Arabidopsis leaves.