Metabolomic spectral biomarker selection towards early diagnostic of Fusarium oxysporum in tomato

Abstract

The interaction of phytopathogenic organisms and plants generates physiological and biochemical changes in the latter, however the effects in the plants are rarely visible in the first stages of infection. Novel optical techniques can help to improve the early detection of the phytopathogenic organisms in tomato plants without the plant sacrifice. In this work infrared spectroscopy and chemometric methods were used in an intent to determinate the effects of Fusarium oxysporum in tomato leaves cultivated in pots. Fusarium oxysporum was molecular identified and its pathogenicity was test in vitro. Three treatments were evaluated, control, water stress, and fungal inoculated plants (1x108 conidia/ml); for 55 days post infection in pots in greenhouse under semi controlled conditions. Phenotypical results were followed twice a week for 8 weeks, the phenotypical characteristics were very similar in almost all sampling times except in height specially in the first 27 days post infection, after this time the height was similar in the three treatments. The stalk and root dried matter analysis does not show statistical differences; however, the infrared results, develop in the adaxial surface of leaves, shows differences in peaks associated to salicylic acid, jasmonic acid, abscisic acid, and proline in the first 27 days post infection. The PCA-LDA development in the time groups, help to have a good classification in the first 27 days as first group, and in the rest of the sampling times as second group.