NMR techniques coupled with multivariate statistical analysis: tools to analyze Oryza sativa metabolic content under stress conditions

Rice (Oryza sativa L.) is one of the most important crops in the world and its growth is influenced by several environmental stresses, such as drought and high salinity. In our work, we first investigated metabolic profile in shoots and roots of two rice cultivars (Arborio and Nipponbare) through 1 H HR MAS and liquid state NMR experiments. Drought and salt stress experiments on shoots and roots growth showed a higher sensitivity of Arborio seedlings than those of Nipponbare to these abiotic stresses. Moreover, the metabolic content of the same samples was analysed by liquid state NMR coupled with multivariate statistical analysis. Principal Component Analysis highlighted a significant accumulation of amino acids and sugars in shoots and roots under stress conditions and the existence of clear differences between the two analyzed rice cultivars. In particular, Arborio seedlings accumulated a higher concentration of amino acids and sugars than Nipponbare ones. Furthermore, we also obtained preliminary data about rice metabolic changes following infection with the fungus Magnaporthe grisea. This work proves that NMR technique coupled with multivariate statistical analysis is a powerful tool to assess a possible correlation between differences in metabolic profile and in tolerance/sensitivity phenotype in rice cultivars.