The beneficial effects of S-methyl-methionine in maize in the case of Maize dwarf mosaic virus infection

Maize dwarf mosaic virus (MDMV) is one of the most common pathogens infecting maize plants. Its infection causes decreased plant growth and chlorotic bands on the leaves giving a mosaic pattern. Our efforts aimed to increase the plants’ inherent resistance with exogenic addition of the natural compound S-methyl-methionine (SMM) that plays a central role in the plant sulphur metabolism. SMM is a key compound in various metabolic pathways connected with resistance mechanisms of several stresses. In the present study Jubilee sweet corns were used, on which the harmful effects of MDMV and the advantageous actions of SMM were recorded applying non-invasive fluorescence imaging and induction methods and DAS-ELISA test. According to the results, the SMM treatment improved the physiological parameters of the maize plants (including photosynthetic rate and the amount of chlorophyll pigments), and nevertheless it significantly improved the plants’ defence response to viral infection

S-methylmethionine alters gene expression of candidate genes in Maize dwarf mosaic virus infected and drought stressed maize plants

In the present work we investigated the potential beneficial effects of the exogenous application of S-methylmethionine (SMM) that plays an important role in the plants’ sulphur metabolism and contributes to the production of certain defence compounds. The possible beneficial effects were challenged against Maize dwarf mosaic virus infection and drought stress. We studied the expression changes of GF14-6 and SAMS during viral infection and DREB2A and DBP2 during drought stress. The product of GF14-6 recognise the viral coat protein and contributes to RNA-silencing, while the product of SAMS plays a central role in the plant sulphur metabolism and contributes to the production of several defence compounds. The products of DREB2A and DBP2 contribute to better plant defence against drought stress and increase the efficiency of water uptake. According to our results, SMM pretreatment has a considerable change on the investigated genes’ expression. It significantly decreases the gene expression of GF14-6, while infection results in a higher expression level. On the other hand, a more prolonged and long lasting increase is measured in SAMS expression as a result to SMM pretreatment followed by infection. SMM lessens the gene expression of DREB2A, while no changes were observed in DBP2 compared to drought stressed plants

Protective role of S-methylmethionine-salicylate in maize plants infected with Maize dwarf mosaic virus

This study aimed to detect the harmful effects of Maize dwarf mosaic virus (MDMV) infection, and to demonstrate the potential benefits of S-methylmethionine-salicylate (MMS) pretreatment in infected maize (Zea mays L.) plants. The results of chlorophyll a fluorescence measurements showed that in MDMV-infected plants additional quenchers of fluorescence appear, probably as the result of associations between the virus coat protein and thylakoid membranes. It is important to note that when infected plants were pretreated with MMS, such associations were not formed. MDMV infection and MMS pretreatment resulted in a decrease in ascorbate peroxidase (APX) activity in maize leaves, while infection contributed to an increase in activity in the roots. Infection raised the guaiacol peroxidase (GPX) enzyme activity level, which was reduced by MMS pretreatment. MMS contributed to a decrease in both the RNA and coat protein content of MDMV, to an equal extent in maize leaves and roots. The results showed that MMS pretreatment enhanced the stress response reactions against MDMV infection in maize plants and retarded the spreading of infection