Research interests

Field of research: epidemiology of infection and diseases of wild and cultivated plants infected with non-cultivable bacteria. Studies of endophytic bacterial microbiomes of diseased and healthy plant hosts. The diversity of beneficial and pathogenic bacteria and their phylogenetic origin are studied. Plant disease management recommendations. Isolation of DNA from various plants, application of various PCR methods (rtPCR, nPCR, MP PCR, microsatellite analysis, etc.), sequencing, DNA fingerprinting and metagenomic analysis; microorganism population structure studies; search for rational means of combating plant diseases.

Annotation of the doctoral dissertation

Purpose: To identify and clarify the influence of berry-damaging phytoplasmas on the berry microbiome using molecular biology methods.
• Collection of symptomatic and asymptomatic berry bushes (Ribes spp., Rubus spp., Fragaria spp., Vaccinium spp., etc.) samples.
• Isolation of plant generic DNA.
• Identification and classification of Candidatus Phytoplasma species using PCR and RFLP analysis.
• Microbiota and microbiome analysis of collected infected and healthy berry bushes
• Multilocus genotyping and phylogenetic analysis of relatedness and origin of ‘Candidatus Phytoplasma’ and other pathogens.
Certain plant diseases, previously classified as viral diseases, are caused by prokaryotic organisms – phytoplasmas. These are bacteria that, due to evolution, have lost the ability to form a cell wall, which is why they are very plastic. Phytoplasmas belong to the group of gram-positive bacteria, do not have a permanent shape and a solid cell wall, so the gram method is not suitable for their classification. According to morphological features, phytoplasmas are similar to mycoplasmas that parasitize animals: they do not have a cell wall, have an indefinite shape, ribosome-like granules are visible at the edges of the cell, and DNA-like structures are visible in the center. As a result, phytoplasmas were called MLO (mycoplasma-like organism). Phytoplasma is able to filter through bacterial filters. For a very long time, it was believed that the change in color of flowers, sterility and other symptoms of plant yellows are caused by viruses, because when filtering plant tissue juices with bacteriological filters, the infection penetrated through them.
A plant infected with phytoplasmas often undergoes morphological changes. These diseases are classified as plant yellows. The first written sources presenting symptoms similar to those caused by phytoplasma infection were found in the 10th century. at the beginning in China. Studies show that phytoplasmas, as a bacterial pathogen, can cause plant dwarfism, phyllody of inflorescences, yellowing or color changes (mosaicism) of the plant or its parts, crushing of leaves or other parts of the plant, unusual branching (“witch’s broom”), retarded development and tissue necrosis. It is assumed that certain indications of diseases (for example, plant phylloidia) are not caused by metabolic products released by the pathogen, but by toxins released by the diseased plant itself. It is like a response to a phytoplasma infection. The assumption that this may be a consequence of phytohormone imbalance caused by phytoplasma infection is also being considered.
Phytoplasma infections can cause a wide range of yellows (for example, ash yellows, aster yellows, onion yellows, etc.). These diseases and their consequences have a great ecological, biological and economic significance not only for Europe, but also for the whole world. Ecological consequences can occur when infection spreads across biologically sensitive areas and destroys animal habitats and food sources. The biological significance of phytoplasma infections is manifested in the fact that they can cause a significant regression of biodiversity: infected plants usually die or remain sterile. This is especially relevant in closed areas: islands or peninsulas, where there is a possibility that the infection will destroy all the plant species characteristic of a particular area and cause great damage to the entire ecosystem of such an area.
Molecular cloning; polymerase chain reaction (rtPCR, In silico PCR nPCR: RT-PCR); gel electrophoresis; chromatography; restriction fragment length polymorphism analysis (RFLP); digital skills: Phyton basics / MS Office user (Microsoft Word Microsoft Excel Microsoft PowerPoint) / ArcGIS mapping and analysis platform/MEGAX/SeqMan/Past3


  1. Dėlkus M. 2021. Dynamics of phytoplasma infection identified in mountain pines (Pinus mugo TURRA) growing in the anthropogenic forest of the Curonian Spit National Park. – Research of young students in protected areas of Lithuania 2021″, balantis, Vilnius, Lithuania.
  2. Dėlkus M. 2022. Phytoplasmas and their influence on infected berry plants. Biofutures: Perspectives in the Natural and Life Sciences, 24 November. Vilnius, Lithuania.