Summary A common argument against using plants as a production system for therapeutic proteins is their inability to perform authentic human N‐glycosylation (i.e. the presence of β1,2‐xylosylation and core α1,3‐fucosylation). In this study, RNA interference (RNAi) technology was used to obtain a targeted down‐regulation of the endogenous β1,2‐xylosyltransferase (XylT) and α1,3‐fucosyltransferase (FucT) genes in Nicotiana benthamiana, a tobacco‐related plant species widely used for recombinant protein expression. Three glyco‐engineered lines with significantly reduced xylosylated and/or core α1,3‐fucosylated glycan structures were generated. The human anti HIV monoclonal antibody 2G12 was transiently expressed in these glycosylation mutants as well as in wild‐type plants. Four glycoforms of 2G12 differing in the presence/absence of xylose and core α1,3‐fucose residues in their N‐glycans were produced. Notably, 2G12 produced in XylT/FucT‐RNAi plants was found to contain an almost homogeneous N‐glycan species without detectable xylose and α1,3‐fucose residues. Plant‐derived glycoforms were indistinguishable from Chinese hamster ovary (CHO)‐derived 2G12 with respect to electrophoretic properties, and exhibited functional properties (i.e. antigen binding and HIV neutralization activity) at least equivalent to those of the CHO counterpart. The generated RNAi lines were stable, viable and did not show any obvious phenotype, thus providing a robust tool for the production of therapeutically relevant glycoproteins in plants with a humanized N‐glycan structure.

Paternity analysis was used to determine the spatial distribution of male parents of 984 offspring collected from 13 identified mother trees in a natural stand of 5.76 ha and comprising 296 adult trees of Quercus petraea and Q. robur. For seven of the 13 maternal progeny arrays sampled, we found an excess of nearby matings and a preferential direction of pollination. For the remaining progeny arrays, no departure from random distribution of male parents was detected. A common trend among all families was a high percentage (averaging 65% for Q. robur and 69% for Q. petraea) of offspring that were pollinated by male parents from outside the study site. By pooling the data over all families, the average pollen dispersal curve within the stand was inferred and fitted to a negative exponential distribution. This model extrapolated for distances over the spatial scale of the study stand was insufficient to explain the high level of gene flow detected by the paternity analysis, suggesting a substantial level of long‐distance pollination events. The genetic composition of the pollen pools received by each maternal tree was compared and showed significant differentiation that could be attributed to differences in male reproductive success. By contrast, no significant differentiation between the pollen clouds from outside and inside the study stand was detected, suggesting genetic homogeneity between the surrounding forest and the study stand.

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Derailed cytokine and immune cell networks account for organ damage and clinical severity of COVID-19 [1][2][3][4] . Here we show that SARS-CoV-2, like other viruses, evokes cellular senescence as a primary stress response in infected cells. Virus-induced senescence (VIS) is indistinguishable from other forms of cellular senescence and accompanied by a senescence-associated secretory phenotype (SASP), composed of pro-inflammatory cytokines, extracellular matrix-active factors and pro-coagulatory mediators [5][6][7] . COVID-19 patients displayed markers of senescence in their airway mucosa in situ and elevated serum levels of SASP factors. Mirroring COVID-19 hallmark features such as macrophage and neutrophil infiltration, endothelial damage and widespread thrombosis in affected lung tissue 1,8,9 , in vitro assays demonstrated macrophage activation with SASP-reminiscent secretion, complement lysis and SASP-amplifying secondary senescence of endothelial cells, neutrophil extracellular trap (NET) formation as well as activation of platelets and the clotting cascade in response to supernatant of VIS cells, including SARS-CoV-2-induced senescence. Senolytics such as Navitoclax and Dasatinib/Quercetin selectively eliminated VIS cells, mitigated COVID-19-reminiscent lung disease and reduced inflammation in SARS-CoV-2-driven hamster and mouse models. Our findings mark VIS as pathogenic trigger of COVID-19-related cytokine escalation and organ damage, and suggest senolytic targeting of virus-infected cells as a novel treatment option against SARS-CoV-2 and perhaps other viral infections.The pandemic human pathogenic SARS-CoV-2 coronavirus causes upper respiratory infections and subsequently COVID-19 lung disease that may get further complicated by septic multi-organ failure and comes with significant mortality 10,11 . Escalating immune activation with massive cytokine release seems to drive severe COVID-19 1-3 , possibly more than the virus infection itself. Mechanisms of viral

The plant glycosyltransferases, L L1,2-xylosyltransferase (XylT) and core K K1,3-fucosyltransferase (FucT), are responsible for the transfer of L L1,2-linked xylose and core K K1,3-linked fucose residues to glycoprotein N-glycans. These glycan epitopes are not present in humans and thus may cause immunological responses, which represent a limitation for the therapeutic use of recombinant mammalian glycoproteins produced in transgenic plants. Here we report the genetic modi¢cation of the N-glycosylation pathway in Arabidopsis thaliana plants. Knockout plants were generated with complete de¢ciency of XylT and FucT. These plants lack antigenic protein-bound Nglycans and instead synthesise predominantly structures with two terminal L LN-acetylglucosamine residues (GlcNAc 2 Man 3 -GlcNAc 2 ).