Microbial perspective on restoration of degraded urban soil using ornamental plants.

The urban soil where abandoned buildings are demolished is barren and structurally poor, and this degraded soil requires restoration. Ornamental plants enhance the urban environment, increase biodiversity, and affect soil physicochemical properties, microbial diversity; however, their effects remain unclear. Thus, in this study, a mixed-planting meadow consisting of 14 perennial ornamental flower species, including Iris tectorum, Iris lacteal, and Patrinia scabiosaefolia, etc. Was planted at a demolition site with sewage-contaminated soil in Beijing. Simultaneously, a single-planting lawn of I. tectorum was established in a nearby park. We aimed to examine soil physicochemical properties, sequence soil bacterial 16S rRNA and fungal ITS amplicons, and analyze soil microbial diversity and community structure at both sites at five time points in the year after planting, To explore the effect of herbaceous ornamental plants on degraded urban soil, we used FAPROTAX and FUNGuild to predict bacterial and fungal functions, the bin-based null model to evaluate the soil microbial community, and random matrix theory to construct soil microbial molecular networks. The mixed-planting meadow produced a visually appealing landscape and dynamic seasonal enrichment, significantly increasing soil total nitrogen (TN) and organic matter (SOM) contents by 1.99 and 1.21 times, respectively. TN had a positive correlation with soil microbial α diversity and community structure. Dominant phyla at both sites included Proteobacteria, Actinobacteria, and Ascomycota. Although soil microorganisms were primarily influenced by stochastic processes, stochasticity was notably higher in the mixed-planting meadow than in the single-planting lawn. The mixed-planting meadow significantly increased the relative abundance of beneficial microorganisms, improving nitrification and aerobic ammonium oxidation of soil bacteria, as well as symbiotroph of fungi. No significant changes were observed in the single-planting lawn. The mixed-planting meadow established a complex soil microbial molecular network, enhancing the correlation between bacteria and fungi and increasing the number of key microorganisms. Our findings suggest the potential of mixed-planting meadow in restoring degraded urban soils by influencing the soil microbial community and enhancing the ecological service function. Our study provides theoretical support for applying mixed-planting meadow communities to improve the soil environment of urban green spaces.

Exploring the relationship between pollen viability and inclusion in Paeonia lactiflora after cryopreservation.

Pollen, as the male gametophyte, carries half of plant genetic information and is an important source of germplasm. The cryopreservation of pollen can not only preserve germplasm, but also solve the problem of time and space barrier in crossbreeding. So it is of great significance to explore the mechanism of pollen viability maintenance after cryopreservation. In this paper, 10 cultivars of Paeonia lactiflora with different fresh pollen viability that did not change after cryopreservation were taken as objects and the effects of pollen inclusions such as soluble sugar, starch, soluble protein, free amino acids, and proline were explored. The results showed that: (1) The contents of pollen inclusions in the fresh pollen of 10 cultivars were different. After cryopreservation, the contents of starch and free amino acids significantly decreased in 10 cultivars, and the soluble sugar, soluble protein, and proline varied with cultivars. (2) Correlation analysis showed that fresh pollen viability was significantly positively correlated with the soluble sugar (R-values of 0.630) and starch content (R-values of 0.694) in fresh pollen. But after cryopreservation pollen viability was only significantly positively correlated with the starch content (R-values of 0.725). These results suggest that the effects of pollen inclusions on pollen vitality are different before and after cryopreservation. The fresh pollen with higher soluble sugar and starch is more vital. But after cryopreservation, the pollen with high starch content has higher viability. The maintenance of stable pollen viability after cryopreservation appears to be related to starch content or starch metabolism, which requires further to study for a final determination.

Changes of pollen viability after preservation of Paeonia lactiflora in different provenances.

Pollen contains all the haploid genetic information of species and is of great significance to preserve germplasm resources safely and effectively. The acquisition of high quality materials is a very important step in germplasm preservation. This study compared the viability and physiological condition of Paeonia lactiflora pollen from several provenances after preservation, to explore the effect of provenance difference on pollen viability and physiological responses after preservation. The results showed that: the pollen viability of two cultivars were significantly different in provenances after preserved at -20 °C or liquid nitrogen (LN) for 3 months, the pollen viability of 'Fen Yu Nu' showed Lanzhou > Beijing > Luoyang > Heze, while the pollen viability of 'Zi Feng Chao Yang' showed Luoyang > Beijing > Heze. Similarly, the oxidative stress levels of the Paeonia lactiflora pollen after preservation with LN or -20 °C were also significantly different among the provenances, and there was a relationship between the viability and the oxidative stress levels produced by the provenances differences. Reactive oxygen species (ROS) content, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and glutamate reductase (GR) activity in pollen from different provenances were contrary to the changes of viability; while catalase (CAT), ascorbic acid peroxidase (APX), ascorbic acid (AsA) and glutathione (GSH) were consistent with the changes of viability. The results indicated that the responses of antioxidant systems of two cultivars pollen to preservation with LN or -20 °C were different in provenances, and this difference was one of the reasons for the different viability of pollen after preservation with LN or -20 °C.

Deletion of miR-15a inhibited glioma development via targeting Smad7 and inhibiting EMT pathway.

In the present study, we found the expression of miR-15a-5p (miR-15a) was increased in glioma tissues, and we further explore the underlying mechanism of miR-15a in glioma progression. Microarray analysis used to identify the differentially expressed microRNAs (miRNAs) in glioma tissues. The expression of miR-15a in glioma tissues and cell lines was tested by qRT-PCR. Luciferase assay was used to determine the binding between miR-15a and Smad7. Wound healing and transwell assay were used to examine the role of miR-15a/Smad7 in SHG139 cells. Western blot was used to detect the protein level of Smad7 and epithelial-mesenchymal transition (EMT) markers. A tumor formation model in nude mice was established to measure the role of miR-15a in vivo. MiR-15a was significantly increased in glioma tissues and cells, which indicated a poor prognosis of glioma patients. MiR-15a mimics induced miR-15a level in SHG139 cells, and promoted the malignancy of SHG139 cells, while miR-15a inhibitor showed the opposite effects. Luciferase assay indicated that Smad7 was the direct target of miR-15a, and Smad7 was down-regulated in glioma tissues. Functional experiments revealed that miR-15a inhibitor inhibited the EMT pathway and the migration and invasion of glioma cells, but the silencing of Smad7 reversed the effects of miR-15a inhibitor in EMT pathway and glioma progression. Finally, we performed animal experiments to verify the role of miR-15a in vivo. Present study showed that deletion of miR-15a inhibited the activation of EMT signaling via targeting Smad7, thus suppressed the tumorigenesis and tumor growth of glioma.