A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces

Article Authors Metrics Comments Related Content Abstract Author summary Introduction Results and discussion Conclusions Methods Supporting information Acknowledgments References Reader Comments (0) Media Coverage (0) Figures Abstract Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast “yeast-like” growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices

How filamentous pathogens co-opt plants: the ins and outs of fungal effectors

Research on effectors secreted by pathogens during host attack has dominated the field of molecular plant–microbe interactions over recent years. Functional analysis of type III secreted effectors injected by pathogenic bacteria into host cells has significantly advanced the field and demonstrated that many function to suppress host defense. Fungal and oomycete effectors are delivered outside the host plasma membrane, and although research has lagged behind on bacterial effectors, we are gradually learning more and more about the functions of these effectors. While some function outside the host cell to disarm defense, others exploit host cellular uptake mechanisms to suppress defense or liberate nutrients intracellularly. Comparative genomics suggests that the organization of effector genes drives effector evolution in many pathogen genomes

Precision in vitreoretinal surgery, manual versus assisted instrument positioning

Ophthalmic researc

Design of an intuitive motion controller for robot-assisted vitreoretinal surgery

Ophthalmic researc

X-ray fluorescence microscopy of zinc localization in wheat grains biofortified through foliar zinc applications at different growth stages under field conditions

Aim: Biofortification of wheat with zinc (Zn) through foliar Zn application has been proposed as an agronomic strategy to increase grain Zn concentration, which could serve as a nutritional intervention in regions with dietary Zn deficiency. Methods: Bread wheat (Triticum aestivum L.) was biofortified through foliar Zn applications at different growth stages. The concentration of Zn and associated micronutrient in harvested whole grains was determined by ICP-OES. Synchrotron-based X-ray fluorescence microscopy (XFM) was then used to investigate the localization of Zn and associated micronutrients in cross sections of these grains. Results: The concentration of Zn and other micronutrients (Mn, Fe, and Cu) was higher in grains treated with foliar Zn during grain-filling (early milk/dough) than those treated at stem elongation. The increase in Zn concentration of wheat grain with foliar application during grain-filling can be attributed to the intense localization of Zn in the aleurone layer, modified aleurone, crease tissue, vascular bundle, and endosperm cavity, and to a modest localization in endosperm, which is the most dominant grain tissue. These tissues and the Zn they contain are presumed to remain after milling and can potentially increase the Zn concentration in wheat flour. Conclusions: By using XFM, it was shown that foliar Zn spray represents an important agronomic tool for a substantial Zn enrichment of different fractions of wheat grain, especially the endosperm. Further investigation of the chemical speciation of Zn in the endosperm is recommended to assess Zn bioavailability in harvested whole grain of wheat that has been biofortified through different timing of foliar Zn application. © 2015, Springer International Publishing Switzerland

Discrepancies between Intraoperative and Histological Evaluation of the Appendix in Acute Appendicitis

Contains fulltext : 226478.pdf (Publisher’s version ) (Closed access)PURPOSE: To identify discrepancies between intraoperative and histological evaluations of the appendix in acute appendicitis and to evaluate the effect on surgical outcome. METHODS: Data was used from our previous multicentre, prospective, cohort study of patients with suspected acute appendicitis. Appendices were scored during intraoperative and histological evaluation as uncomplicated or complicated appendicitis. Primary outcome was percentage of concordance between intraoperative and histological evaluation. Secondary outcomes were (infectious) postoperative complications, length of hospital stay, hospital re-admission and re-intervention rate, all within 30 days of surgery. RESULTS: A total of 1850 patients were included. In 65.7% (1215/1850) of the appendices, the intraoperative evaluation was uncomplicated and in 34.3% (635/1850), complicated appendicitis. Patients with uncomplicated appendicitis had a postoperative course with significantly less postoperative complications (7.2% vs 24.3%), a shorter length of hospital stay (2 vs 5 days) and a lower re-admission (4.2% vs 9.6%) and re-intervention rate (1.1% vs 4.3%) than intraoperative complicated appendicitis (p < 0.001). In 93.5% (1136/1215) of the intraoperative uncomplicated patients and in 46.6% (296/635) of the intraoperative complicated patients, there was an agreement with pathology (Kappa 0.45). In 23.9% (81/339) of patients with intraoperative complicated and histological uncomplicated appendicitis, a postoperative complication was observed, which was similar to the postoperative complication rate of complicated appendicitis both on intraoperative and histological evaluation (24.7% (73/296)). CONCLUSIONS: There is a moderate agreement between a surgeon and pathologist in diagnosing patients with complicated appendicitis. However, the intraoperative diagnosis of complicated appendicitis was significantly associated with postoperative complications. Routine histological evaluation should be preserved for excluding malignancies in suspect appendices