Mosses: Accessible Systems for Plant Development Studies

Mosses are a cosmopolitan group of land plants, sister to vascular plants, with a high potential for molecular and cell biological research. The species Physcomitrium patens has helped gaining better understanding of the biological processes of the plant cell, and it has become a central system to understand water-to-land plant transition through 2D-to-3D growth transition, regulation of asymmetric cell division, shoot apical cell establishment and maintenance, phyllotaxis and regeneration. P. patens was the first fully sequenced moss in 2008, with the latest annotated release in 2018. It has been shown that many gene functions and networks are conserved in mosses when compared to angiosperms. Importantly, this model organism has a simplified and accessible body structure that facilitates close tracking in time and space with the support of live cell imaging set-ups and multiple reporter lines. This has become possible thanks to its fully established molecular toolkit, with highly efficient PEG-assisted, CRISPR/Cas9 and RNAi transformation and silencing protocols, among others. Here we provide examples on how mosses exhibit advantages over vascular plants to study several processes and their future potential to answer some other outstanding questions in plant cell biology

Enhancing Localized Pesticide Action through Plant Foliage by Silver-Cellulose Hybrid Patches

Efficacy and efficiency of pesticide application in the field through the foliage still face many challenges. There exists a mismatch between the hydrophobic character of the leaf and the active molecule, low dispersion of the pesticides on the leaves' surface, runoff loss, and rolling down of the active molecules to the field, decreasing their efficacy and increasing their accumulation to the soil. We produced bacterial cellulose-silver nanoparticles (BC-AgNPs) hybrid patches by in situ thermal reduction under microwave irradiation in a scalable manner and obtaining AgNPs strongly anchored to the BC. Those hybrids increase the interaction of the pesticide (AgNPs) with the foliage and avoids runoff loss and rolling down of the nanoparticles. The positive antibacterial and antifungal properties were assessed in vitro against the bacteria Escherichia coli and two agro-economically relevant pathogens: the bacterium Pseudomonas syringae and the fungus Botrytis cinerea. We showed in vivo inhibition of the infection in Nicotiana benthamiana and tomato leaves, as proven by the suppression of the expression of defense molecular markers and reactive oxygen species production. The hydrogel-like character of the bacterial cellulose matrix increases the adherence to the foliage of the patches

Enhancing localized pesticide action through the plant foliage by silver-cellulose hybrid patches

Efficacy and efficiency of pesticide application in the field through the foliage still faces many challenges. There exists a mismatch between the hydrophobic character of the leaf and the active molecule, low dispersion of the pesticides on the leaves’ surface, runoff loss and rolling down of the active molecules to the field, decreasing their efficacy and increasing their accumulation to the soil. We produced bacterial cellulose-silver nanoparticles hybrid patches by in situ thermal reduction under microwave irradiation in a scalable manner and obtaining AgNPs strongly anchored to the BC. Those hybrids increase the interaction of the pesticide (AgNPs) with the foliage and avoids runoff loss and rolling down of the nanoparticles. The positive anti-bacterial and anti-fungal properties were assessed in vitro against the bacteria Escherichia coli and two agro-economically relevant pathogens: the bacterium Pseudomonas syringae and the fungus Botrytis cinerea. We showed in vivo inhibition of the infection in Nicotiana benthamiana and tomato leaves, as proven by the suppression of the expression of defense molecular markers and reactive oxygen species production. The hydrogel-like character of the bacterial cellulose matrix increases the adherence to the foliage of the patches.We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) with grants 2016-78002-R (AGL) and RyC 2014-16158 (NSC), MAT2015-64442-R, FIP and through the “Severo Ochoa Programme for Centres of Excellence in R&D” (SEV-2015-0533 and SEV-2015-0496). This work was also supported by the CERCA Programme / Generalitat de Catalunya, the Generalitat de Catalunya for the 2017SGR765 project.Peer reviewe

Cellulose patches in plants

Resumen del trabajo presentado al 4th International Symposium on Bacterial Nanocellulose, celebrado en Oporto (Portugal) del 3 al 4 de octubre de 2019

Signaling platforms assembled in plant cells upon pathogen perception

Trabajo presentado al XVIII Congreso de la Sociedad Española de Biología Celular, celebrado en Badajoz del 15 al 18 de octubre de 2019

Enhancing Localized Pesticide Action through Plant Foliage by Silver-Cellulose Hybrid Patches

Efficacy and efficiency of pesticide application in the field through the foliage still face many challenges. There exists a mismatch between the hydrophobic character of the leaf and the active molecule, low dispersion of the pesticides on the leaves' surface, runoff loss, and rolling down of the active molecules to the field, decreasing their efficacy and increasing their accumulation to the soil. We produced bacterial cellulose-silver nanoparticles (BC-AgNPs) hybrid patches by in situ thermal reduction under microwave irradiation in a scalable manner and obtaining AgNPs strongly anchored to the BC. Those hybrids increase the interaction of the pesticide (AgNPs) with the foliage and avoids runoff loss and rolling down of the nanoparticles. The positive antibacterial and antifungal properties were assessed in vitro against the bacteria Escherichia coli and two agro-economically relevant pathogens: the bacterium Pseudomonas syringae and the fungus Botrytis cinerea. We showed in vivo inhibition of the infection in Nicotiana benthamiana and tomato leaves, as proven by the suppression of the expression of defense molecular markers and reactive oxygen species production. The hydrogel-like character of the bacterial cellulose matrix increases the adherence to the foliage of the patches

One-Step Biosynthesis of Soft Magnetic Bacterial Cellulose Spheres with Localized Nanoparticle Functionalization

Actuated structures are becoming relevant in medical fields; however, they call for flexible/soft-base materials that comply with biological tissues and can be synthesized in simple fabrication steps. In this work, we extend the palette of techniques to afford soft, actuable spherical structures taking advantage of the biosynthesis process of bacterial cellulose. Bacterial cellulose spheres (BCS) with localized magnetic nanoparticles (NPs) have been biosynthesized using two different one-pot processes: in agitation and on hydrophobic surface-supported static culture, achieving core-shell or hollow spheres, respectively. Magnetic actuability is conferred by superparamagnetic iron oxide NPs (SPIONs), and their location within the structure was finely tuned with high precision. The size, structure, flexibility and magnetic response of the spheres have been characterized. In addition, the versatility of the methodology allows us to produce actuated spherical structures adding other NPs (Au and Pt) in specific locations, creating Janus structures. The combination of Pt NPs and SPIONs provides moving composite structures driven both by a magnetic field and a H2O2 oxidation reaction. Janus Pt/SPIONs increased by five times the directionality and movement of these structures in comparison to the controls.Authors acknowledge financial support from the Spanish Ministry of Science and Innovation through the RTI2018-096273-B-I00 project, the “Severo Ochoa” Programme for the Centres of Excellence in R&D (CEX2019-000917-S), and the PhD scholarship of S.R.-S (BES-2016-077533). The Generalitat de Catalunya project 2017SGR765 is also acknowledged. The authors also express their gratitude to the technical services of ICMAB-CSIC (electron microscopy, magnetometry and Nanoquim facilities) and CRAG (microscopy facilities). The authors participate in the CSIC Interdisciplinary Platform for Sustainable Plastics toward a Circular Economy, SUSPLAST, the EPNOE Association, Ministerio de Ciencia e Innovación, Acciones de dinamización Redes de Investigación RED2018-102469-T and in the Aerogels COST ACTION (CA 18125).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe