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.

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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.

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.

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