Effect of <i>Meloidogyne incognita</i> infection on the accumulation of phenolic compounds in plants of the genus Mint (Mentha L.)

Abstract

The purpose of the research is to compare the accumulation of phenolic compounds of different species and varieties of mint, zoned in Central Russia against the background of plant infection by Meloidogyne incognita.Materials and methods. Plants were grown from cuttings in a growing experiment in open ground. Mentha × piperita L. (varieties: Tik-Tak, Orange, Minneola, Mojito, Mitchum, Chocolate), M. spicata L. (varieties Morocco, Crispa) and M. longifolia L. (Longifolia) were taken for the study. A month later, the rooted plants were infected at the rate of 1000 sp. infective larvae of M. incognita per plant. After 8 weeks leaves were fixed in ethanol. The total content of phenolic compounds (PC), phenylpropanoids, flavonoids and catechins was studied using a spectrophotometer. The determination of the total content of PС was carried out using the Folin-Cecolte reagent with measurement at 725 nm, phenylpropanoids – by direct measurement of optical density at 330 nm, flavonoids – by reaction with aluminum chloride at 415 nm, the total content of flavans (catechins - flavan-3-ols), their oligomeric forms – proanthocyanidins, as well as leukoanthocyanidins were assessed by reaction with vanillin at 500 nm.Results and discussion. It has been shown that the accumulation of phenols is related to the species of plants. The varieties Mentha × piperita L. in most cases contained more phenols than M. spicata L. and M. longifolia L. A significant number of PC was noted in the violet-colored varieties Mitchum, Chocolate and Orange. The total content of PC almost completely correlates with the content of their precursors – phenylpropanoids. In terms of the content of flavonoids, the Mitchum variety stands out noticeably, and in terms of the content of catechins, the Orange variety stands out. Nematode infection in most varieties causes a noticeable increase in the total accumulation of soluble PC, phenylpropanoids and flavans, but leads to a decrease in the content of flavonoids.