ER body-resident myrosinases and tryptophan specialized metabolism modulate root microbiota assembly.

Endoplasmic reticulum (ER) bodies are ER-derived structures that contain a large amount of PYK10 myrosinase, which hydrolyzes tryptophan (Trp)-derived indole glucosinolates (IGs). Given the well-described role of IGs in root-microbe interactions, we hypothesized that ER bodies in roots are important for interaction with soil-borne microbes at the root-soil interface. We used mutants impaired in ER bodies (nai1), ER body-resident myrosinases (pyk10bglu21), IG biosynthesis (myb34/51/122), and Trp specialized metabolism (cyp79b2b3) to profile their root microbiota community in natural soil, evaluate the impact of axenically collected root exudates on soil or synthetic microbial communities, and test their response to fungal endophytes in a mono-association setup. Tested mutants exhibited altered bacterial and fungal communities in rhizoplane and endosphere, respectively. Natural soils and bacterial synthetic communities treated with mutant root exudates exhibited distinctive microbial profiles from those treated with wild-type (WT) exudates. Most tested endophytes severely restricted the growth of cyp79b2b3, a part of which also impaired the growth of pyk10bglu21. Our results suggest that root ER bodies and their resident myrosinases modulate the profile of root-secreted metabolites and thereby influence root-microbiota interactions.

Animal-vehicle collisions during the COVID-19 lockdown in early 2020 in the Krakow metropolitan region, Poland.

The interrelations between human activity and animal populations are of increasing interest due to the emergence of the novel COVID-19 and the consequent pandemic across the world. Anthropogenic impacts of the pandemic on animals in urban-suburban environments are largely unknown. In this study, the temporal and spatial patterns of urban animal response to the COVID-19 lockdown were assessed using animal-vehicle collisions (AVC) data. We collected AVC data over two 6-month periods in 2019 and 2020 (January to June) from the largest metropolis in southern Poland, which included lockdown months. Furthermore, we used traffic data to understand the impact of lockdown on AVC in the urban area. Our analysis of 1063 AVC incidents revealed that COVID-19 related lockdown decreased AVC rates in suburban areas. However, in the urban area, even though traffic volume had significantly reduced, AVC did not decrease significantly, suggesting that lockdown did not influence the collision rates in the urban area. Our results suggest that there is a need to focus on understanding the effects of changes in traffic volume on both human behaviour and wildlife space use on the resulting impacts on AVC in the urban area.

Texture feature extraction from microscope images enables a robust estimation of ER body phenotype in Arabidopsis.

BACKGROUND: Cellular components are controlled by genetic and physiological factors that define their shape and size. However, quantitively capturing the morphological characteristics and movement of cellular organelles from micrograph images is challenging, because the analysis deals with complexities of images that frequently lead to inaccuracy in the estimation of the features. Here we show a unique quantitative method to overcome biases and inaccuracy of biological samples from confocal micrographs. RESULTS: We generated 2D images of cell walls and spindle-shaped cellular organelles, namely ER bodies, with a maximum contrast projection of 3D confocal fluorescent microscope images. The projected images were further processed and segmented by adaptive thresholding of the fluorescent levels in the cell walls. Micrographs are composed of pixels, which have information on position and intensity. From the pixel information we calculated three types of features (spatial, intensity and Haralick) in ER bodies corresponding to segmented cells. The spatial features include basic information on shape, e.g., surface area and perimeter. The intensity features include information on mean, standard deviation and quantile of fluorescence intensities within an ER body. Haralick features describe the texture features, which can be calculated mathematically from the interrelationship between the pixel information. Together these parameters were subjected to multivariate analysis to estimate the morphological diversity. Additionally, we calculated the displacement of the ER bodies using the positional information in time-lapse images. We captured similar morphological diversity and movement within ER body phenotypes in several microscopy experiments performed in different settings and scanned under different objectives. We then described differences in morphology and movement of ER bodies between A. thaliana wild type and mutants deficient in ER body-related genes. CONCLUSIONS: The findings unexpectedly revealed multiple genetic factors that are involved in the shape and size of ER bodies in A. thaliana. This is the first report showing morphological characteristics in addition to the movement of cellular components and it quantitatively summarises plant phenotypic differences even in plants that show similar cellular components. The estimation of morphological diversity was independent of the cell staining method and the objective lens used in the microscopy. Hence, our study enables a robust estimation of plant phenotypes by recognizing small differences in complex cell organelle shapes and their movement, which is beneficial in a comprehensive analysis of the molecular mechanism for cell organelle formation that is independent of technical variations.

Vacuolar processing enzymes in the plant life cycle.

Vacuolar processing enzyme (VPE) is a cysteine-type endopeptidase that has a substrate-specificity for asparagine or aspartic acid residues and cleaves peptide bonds at their carboxyl-terminal side. Various vacuolar proteins are synthesized as larger proprotein precursors, and VPE is an important initiator of maturation and activation of these proteins. It mediates programmed cell death (PCD) by provoking vacuolar rupture and initiating the proteolytic cascade leading to PCD. Vacuolar processing enzyme also possesses a peptide ligation activity, which is responsible for producing cyclic peptides in several plant species. These unique functions of VPE support developmental and environmental responses in plants. The number of VPE homologues is higher in angiosperm species, indicating that there has been differentiation and specialization of VPE function over the course of evolution. Angiosperm VPEs are separated into two major types: the γ-type VPEs, which are expressed mainly in vegetative organs, and the ß-type VPEs, whose expression occurs mainly in storage organs; in eudicots, the δ-type VPEs are further separated within γ-type VPEs. This review also considers the importance of processing and peptide ligation by VPE in vacuolar protein maturation.