Marta Jurga

The production and quality of wheat and maize grain can be significantly affected by various pests and pathogens, with phytoplasmas posing a particular threat due to their rapid spread and potential to cause severe damage to cultivated crops. The objective of this investigation was to evaluate the risk associated with these wall-less bacteria in wheat and maize crops. To achieve this, a survey was conducted in commercial fields located in southwestern Poland. Samples of winter wheat and fodder maize were collected at two distinct developmental stages, including both symptomatic and asymptomatic plants. Symptoms observed in wheat included yellowing, stunting, and excessive tillering, while maize plants showed yellow leaf striping, red discoloration, and stunted growth. Polymerase chain reaction (PCR) assays using phytoplasma-specific primers, followed by Sanger sequencing and sequence analysis, confirmed phytoplasma infections in 2% of wheat and 1.5% of maize samples. Virtual restriction fragment length polymorphism (RFLP) analysis identified the wheat-infecting phytoplasmas as belonging to subgroup 16SrI-C (‘Candidatus Phytoplasma tritici’-related strain)—a pathogen of major concern for wheat, while maize-infecting phytoplasmas were classified into subgroups 16SrI-B and 16SrV-C. Additionally, wheat plants collected during the early elongation phase were tested for Mastrevirus hordei (former wheat dwarf virus, WDV) using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), which confirmed the presence of WDV in all tested samples. Preliminary screening of field-collected leafhoppers revealed that 7.5% of Psammotettix alienus, the predominant species in wheat fields, carried 16SrI-C phytoplasmas. In maize fields, Zyginidia scutellaris was the most prevalent species, with 1.7% of individuals carrying 16SrV-C phytoplasma. These findings suggest that these insect species may contribute to the transmission of phytoplasmas in wheat and maize. This study provides the first documented evidence of 16SrI-C phytoplasma infecting wheat in Poland, and of 16SrV-C and 16SrI-B phytoplasmas infecting maize, expanding the known host range of these subgroups in the country and highlighting their potential phytosanitary importance.

The aim of the study was to assess the species composition of the mycobiota inhabiting selected legally protected plant species in Wigry National Park. The research was conducted during the 2024 growing season and included 12 plant species from which leaves with leaf spot symptoms were collected. Based on morphological and molecular analyses a total of 41 fungal taxa were isolated. The most abun­dant species were Alternaria alternata and Cladosporium pseudocladosporioides. The results highlight the necessity of implementing constant phytopathological monitoring as an essential component of habitat and species protection strategies, which may be crucial for preserving plant health and biodiversity.

Honey bee workers ( Apis mellifera L.) collect nectar, honeydew and pollen from plants in orderto provide the colony with, among others, carbohydrates and protein. Whenever these sources are unavailable in the environment, bees turn to alternatives. An example of this are fungi spores collected accidentally or on purpose. This last phenomenon is the aim of this study, in which we have shown that worker bees can collect willow rust ( Melampsora spp.) spores. We observed as the bees obtained spores and placed them in pollen baskets. The presence of spores was demonstrated with the use of a scanning electron microscope (SEM). This observation indicates that the honey bee may use alternative sources as a potential supplement. There are few studies in this field and it requires a deeper analysis.

Small balsam (Impatiens parviflora DC.), an invasive plant native to central Asia, is currently one of the most extensive invasive plants in Central Europe, including Poland. Its expansion may affect populations of native species, such as touch-me-not balsam (Impatiens noli-tangere). It is particularly dangerous in legally protected areas, where the possibilities of eradicating it are very limited. There is some hope for stopping its expansion by using pathogens as a biological weapon. In this case, useful may be host-specific rust fungus Puccinia komarovii var. komarovii. Our three-year observations of I. parviflora infection severity by P. komarovii var. komarovii carried out in Poland in Drawa National Park (DNP) and Wigry National Park (WNP) showed the higher incidence of rust on leaves in DNP, where the median blade infestation for two years was 51% of leaf coverage. In contrast, for three years in WNP, the median blade infestation amounted to only 25%. The most severe symptoms occurred during the summer months. However the percentage of leaf coverage by pathogen exhibited fluctuations depending on the year, implying an influence of environmental conditions that stabilized the infection each season. Molecular analyses, in addition to confirming the infection of the tested plants by P. komarovii var. komarovii, enabled the characterization of its population based on comparative analysis of ITS and LSU sequences. Clear differences were found between the studied isolates and P. komarovii from I. glanduliferae and I. brachycentra. There was no diversity among our isolates, but they differed from the sequences of Polish isolates originating from I. parviflora available in GenBank, which indicates some diversity of rust in a relatively small area. It probably results from sexual reproduction and may enable rapid adaptation of the pathogen to the region or host plant, or it may indicate certain “entry points” to Poland, where the isolates arrived from their native place of occurrence.

In this paper, a lab-on-chip system dedicated to fungi cultivation in Earth’s gravity and simulated microgravity, being a solution that could be used in future nanosatellite missions, is shown. For the first time, a fully glass lab-on-chip structure enabling the proper environment for cultivation of fungi species—Fusarium culmorum—is presented. Apart from the biological validation of the fungi cultures with the use of the lab-on-chip system, tests were carried out under induced microgravity utilising a Rotary Wall Vessel. Correct functioning of the lab-on-chip system was obtained, enabling the growth of fungi spores both in ground and in simulated microgravity conditions. Interestingly, culturing tests have shown that microgravity stimulates the growth of fungi notably, compared to the ground-based experimentation performed simultaneously. The findings of this study can provide substantial new knowledge on microscopic fungi cultivation in lab-on-chip devices, other soil organisms, as well as a potential behavior of these species in microgravity conditions. Culturing system shown in this work can help mycologists to provide better understanding of microscopic fungi nature and their development mechanisms at a single spore level. This opens the way towards regular usage of microfluidic tools in agriculture and horticulture fields and more importantly, in future research on microscopic fungi in space, e.g., as a part of nanosatellite missions.

The activity of some soil organisms can significantly influence the growth of plants. One of the more common are Collembola, which play an important role in suppressing soil-borne pathogens such as Fusarium spp. Here, Folsomia candida was taken for laboratory studies. The aim of the study was to assess whether springtails influence the growth of wheat and pea plants. The purpose was also to evaluate whether Collembola will reduce the occurrence of fungal diseases, presumably by feeding on fungi. The factors tested were (1) wheat grown individually or in the mixture with pea; (2) number of Collembola; and (3) the pathogenic presence of the plant fungus Fusarium culmorum. The experiment was carried out in four replicates for each treatment in two series. The soil used for the test was a mixture of field soil, sand, and peat. The following analyses were performed: measuring plant growth and decomposition rate, assessment of plant infection, and assessment of F. culmorum in springtails bodies. There was no effect of F. culmorum infection on plant growth, although the pathogen was present in the root neck of the plants incubated with this fungus. Collembola decreased the number of fungus colonies isolated from plants by about 45% in comparison to pots incubated without these organisms. The decomposition of plant biomass was accelerated by springtails by about 7% in the pots with moderate Collembola number. However, this was not related to improved plant growth. Additionally, F. culmorum was isolated from the bodies of Collembola, indicating its ability to feed on this fungus. To conclude, it was found that Collembola can decrease pathogenic fungal growth. This issue needs further studies in relation to other plants and fungus species, as well to study observed effects in the field conditions.

Yellowing of leaf tissue and strongly deformed shoots were observed in common mugwort (Artemisia vulgaris L.) growing in a nature reserve in Southern Poland. Similar foliage chlorosis together with abnormal shoot proliferation was noticed on alder tree (Alnus glutinosa Gaertn.) growing next to the common mugwort. DNA specific fragments coding 16S rRNA and ribosomal proteins (rp) were amplified from mugwort and alder samples using direct and nested PCR (Polymerase Chain Reaction) assays. Phylogenetic relationships inferred from 16S and rps3 genes indicated that strains infecting mugwort and alder were most closely related to phytoplasmas of subgroups 16SrV‐C and 16SrV‐D. Based on the restriction fragment length polymorphism (RFLP) analysis of the 16S rDNA, the investigated phytoplasma strains were classified to subgroup 16SrV‐C. Two sequence variants of the rps3 gene which differed by a single nucleotide were detected in all analysed samples by pairwise analysis of the aligned reads. Taking into account that this single‐nucleotide polymorphism (SNP) occurs among 16SrV‐C and 16SrV‐D related phytoplasmas and that the phytoplasmas have a single copy of rp operon, we concluded that each plant species was infected by two distinct, closely related phytoplasma strains. To the best of our knowledge, this is the first report of group 16SrV‐C related phytoplasmas infecting common mugwort worldwide, adding a new host species that is possibly linked to the spread of the alder pathogen in Eastern Europe. Although alder yellows phytoplasma has been frequently found in Europe, this is the first detection of phytoplasmas associated with alder in Poland.