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Abstract Background The rhizosheath, a cohesive soil layer firmly adhering to plant roots, plays a vital role in facilitating water and mineral uptake. In pearl millet, rhizosheath formation is genetically controlled and influenced by root exudates. Here, we investigated the impact of root exudates on the microbiota composition, interactions, and assembly processes, and rhizosheath structure in pearl millet using four distinct lines with contrasting soil aggregation abilities. Results Utilizing 16S rRNA gene and ITS metabarcoding for microbiota profiling, coupled with FTICR-MS metabonomic analysis of metabolite composition in distinct plant compartments and root exudates, we revealed substantial disparities in microbial diversity and interaction networks. The ß-NTI analysis highlighted bacterial rhizosphere turnover driven primarily by deterministic processes, showcasing prevalent homogeneous selection in root tissue (RT) and root-adhering soil (RAS). Conversely, fungal communities were more influenced by stochastic processes. In bulk soil assembly, a combination of deterministic and stochastic mechanisms shapes composition, with deterministic factors exerting a more pronounced role. Metabolic profiles across shoots, RT, and RAS in different pearl millet lines mirrored their soil aggregation levels, emphasizing the impact of inherent plant traits on microbiota composition and unique metabolic profiles in RT and exudates. Notably, exclusive presence of antimicrobial compounds, including DIMBOA and H-DIMBOA, emerged in root exudates and RT of low aggregation lines. Conclusions This research underscores the pivotal influence of root exudates in shaping the root-associated microbiota composition across pearl millet lines, entwined with their soil aggregation capacities. These findings underscore the interconnectedness of root exudates and microbiota, which jointly shape rhizosheath structure, deepening insights into soil–plant-microbe interactions and ecological processes shaping rhizosphere microbial communities. Deciphering plant–microbe interactions and their contribution to soil aggregation and microbiota dynamics holds promise for the advancement of sustainable agricultural strategies. Video Abstract

During the last 15 years, amid the global impacts of the economic crisis, austerity politics, and increasing centrality of real estate and construction for capitalism, housing has taken central stage in public and political debates globally. In Italy, the trajectory of housing politicisation has been quite peculiar. Despite a longstanding tradition of housing conflict and a complex geography of new mobilisations, housing has remained at the margins of national discussions. Seen through the lens of Foucauldian problematisation analysis, housing has not been acknowledged as a ‘problem’ in Italy. This article engages with the Italian peculiarity through a comparative study of housing problematisation—operationalised through the dimensions of framing, coalitions and scale. I compare two cities where analogous challenges intersect with very different housing regimes and political contexts: in Turin, the capacity of short-term housing policies to address pressing problems is mirrored by a lack of engagement by institutional and politicised actors; in Naples, in a housing regime defined by informal solutions, the relations among the local authorities and social movements have oscillated among dialogue, conflict, institutionalisation and pacification. By putting these cases in conversation through a generative, relational and multi-scalar lens, I discuss housing problematisation in a country, Italy, characterised by deep regional asymmetries, regionally-specific housing regimes and a complex geography of housing conflict. By reconsidering the national case vis-à-vis broader dynamics, in conclusion, I also provide some takeaways for a reflection on the conditions, preconditions and efforts for scaling up the housing struggle.

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The response of Alnus glutinosa to Frankia alni ACN14a is driven by several sequential physiological events from calcium spiking and root-hair deformation to the development of the nodule. Early stages of actinorhizal symbiosis were monitored at the transcriptional level to observe plant host responses to Frankia alni. Forty-two genes were significantly upregulated in inoculated compared with noninoculated roots. Most of these genes encode proteins involved in biological processes induced during microbial infection, such as oxidative stress or response to stimuli, but a large number of them are not differentially modulated or downregulated later in the process of nodulation. In contrast, several of them remained upregulated in mature nodules, and this included the gene most upregulated, which encodes a nonspecific lipid transfer protein (nsLTP). Classified as an antimicrobial peptide, this nsLTP was immunolocalized on the deformed root-hair surfaces that are points of contact for Frankia spp. during infection. Later in nodules, it binds to the surface of F. alni ACN14a vesicles, which are the specialized cells for nitrogen fixation. This nsLTP, named AgLTP24, was biologically produced in a heterologous host and purified for assay on F. alni ACN14a to identify physiological effects. Thus, the activation of the plant immunity response occurs upon first contact, while the recognition of F. alni ACN14a genes switches off part of the defense system during nodulation. AgLTP24 constitutes a part of the defense system that is maintained all along the symbiosis, with potential functions such as the formation of infection threads or nodule primordia to the control of F. alni proliferation. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Over the last 30 years, the description of microbial diversity has been mainly based on culture-independent approaches (metabarcoding and metagenomics) allowing an in-depth analysis of microbial diversity that no other approach allows. Bearing in mind that culture-dependent approaches cannot replace culture-independent approaches, we have improved an original method for isolating strains consisting of “culturing” grains of sand directly on Petri dishes (grain-by-grain method). This method allowed to cultivate up to 10% of the bacteria counted on the surface of grains of the three sites studied in the Great Western Erg in Algeria (Timoudi, Béni Abbès, and Taghit), knowing that on average about 10 bacterial cells colonize each grain. The diversity of culturable bacteria (collection of 290 strains) predicted by 16S rRNA gene sequencing revealed that Arthrobacter subterraneus, Arthrobacter tecti, Pseudarthrobacter phenanthrenivorans, Pseudarthrobacter psychrotolerans, and Massilia agri are the dominant species. The comparison of the culture-dependent and -independent (16S rRNA gene metabarcoding) approaches at the Timoudi site revealed 18 bacterial genera common to both approaches with a relative overestimation of the genera Arthrobacter/Pseudarthrobacter and Kocuria, and a relative underestimation of the genera Blastococcus and Domibacillus by the bacterial culturing approach. The bacterial isolates will allow further study on the mechanisms of tolerance to desiccation, especially in Pseudomonadota (Proteobacteria).

During the years of economic crisis and austerity, and the subsequent economic growth dependent on real estate and tourism, housing has returned into the spotlight on the political agenda in Southern European countries and cities, where activists and social movements scaled up their struggles and created bridges with institutional actors, fostering policy change. The latter, however, did not happen in Italy. In this article, based on exploratory case study research carried out in the city of Turin, we present three themes that help explain what we call the 'absent politicization' of housing in Italy during the last decade: a multi-actor, multilevel housing policy capable of defusing specific problems; the absence of bridges between politicized and institutional actors; and the role played by party-politics, with attention to 'populist' Movimento 5 Stelle in power in Turin. By focusing on differences with Southern Europe, we contribute to overcoming dichotomies that have long dominated comparative housing studies; and contribute to linking housing studies with contentious urban politics in the post-crisis years.

This Update reports from a webinar on the impacts on the right to housing and linked political struggles of the lockdown measures put in place globally amid the Covid-19 pandemic. Three main threads emerged through the conversation: the impacts of the pandemic are deepening pre-existing housing inequalities, while governments’ responses are largely insufficient; activists and contentious actors worldwide are changing their framings and repertoires to adapt to lockdown measures and attempt to radicalise their action; possibilities, albeit limited, are opening for the construction of global networks of struggle.

In this section, we reflect, both empirically and speculatively, on the perspectives for STRs and related digital platforms in the (post-)pandemic city, on the grounds of early signals of change in relation to spatial justice and institutional arrangements. The discussion is opened by Tulumello and Cocola-Gant, who, by investigating the case of Lisbon, Portugal, reflect on the flexible nature of platforms vis-à-vis the (neoliberal) cloud of de- and re-regulation in housing and rental markets, discussing how this intersection allows STRs to adapt and succeed, also during the pandemic. Similarly, Iacovone explores the professionalisation of platform-mediated STRs and their adaptability to increasingly more flexible and malleable requests from the market – dimensions that allow them to successfully outcompete smaller actors. Finally, Pettas and Dagkouli–Kyriakoglou, by focusing on the case of Athens, Greece, discuss the ways STRs could be transformed into housing infrastructure for remote workers in connection to the restructuring of the post-pandemic labour market.

The Caravana pelo Direito à Habitação travelled across Portugal together with local groups and associations to collect information on and give visibility to housing needs, while aiming to create new networks and influence the national political agenda. This conversation brings together seven scholar-activists that participated in the Caravana, who reflect upon the Caravana and contemporary struggles on the right to housing in Portugal. The conversation sheds light on some contentious issues that are presented through a selection of relevant excerpts, which cover personal identities as scholar-activists; contexts shaping contemporary housing struggles; and the relation of the Caravana to the the politics of housing in Portugal.

Resumo Lisboa encontra-se em transição. Ao sair de uma crise económica acompanhada por severas políticas de austeridade, encontra-se numa nova fase de dinamismo económico, mas sem conseguir inverter antigas e novas estruturas de desigualdade social e territorial. Este artigo, ao mostrar as recentes transformações do mercado imobiliário e da habitação na principal cidade portuguesa, bem como os movimentos sociais preocupados com o direito à habitação, questiona as articulações entre desenvolvimento local e modelos da nova economia global. A recente história de Lisboa é apresentada como caso paradigmático das disputas entre modelos pseudoliberais de desenvolvimento económico e urbano, e a paulatina formação de suas contestações locais, sobretudo sociais mas também institucionais e, decerto, crescentemente interligadas em redes internacionais.