Biology subjects

Isticato, R.

Publications and source records attributed to Isticato, R..

5 recordsLinked to original sources

bioRxiv2026

From acidic extreme environments to agriculture: a multi-stress-tolerant Talaromyces pseudofuniculosus enhances soybean growth under abiotic stress

Extremophilic fungi are a relatively unexplored source of stress-resilient microbes for sustainable agriculture. Here, we describe Talaromyces pseudofuniculosus FAR, isolated from the highly acidic site of Piccolo Inferno in southern Italy and identified by ITS and {beta}-tubulin (BenA) sequencing. Despite its origin from an extreme environment, T. pseudofuniculosus FRA remained fully functional under non-stress conditions and displayed tolerance to salinity and heavy metals while maintaining key plant growth-promoting traits, including phosphate solubilization, auxin-related compound production and hydrolytic activities. In soybean (Glycine max L.), the live fungus promoted plant growth under both non-stress conditions and agriculturally relevant salinity and copper stress, and successfully colonized the roots. A cell-free extracellular extract (exCFS) promoted early seedling development in vitro, but its effects were not sustained in pot experiments. GC-MS analysis provided a qualitative characterization of the extracellular metabolite profile and revealed condition-dependent differences between control, NaCl and CuSO4; growth conditions, indicating environment-dependent modulation of fungal metabolism. Overall, these findings highlight the physiological and metabolic plasticity of T. pseudofuniculosus FRA and support its potential as a fungal biostimulant for saline- and metal-impacted agricultural soils.

microbiology↗

bioRxiv2025

Trace metals availability controls terminal electron acceptor utilization in Escherichia coli

Trace metals play an essential role in the metabolism of all living organisms and many metal-containing enzymes contribute to key physiological and ecological processes such as aerobic and anaerobic respiration, photosynthesis, carbon and nitrogen fixation. Despite this, trace metals potential to control microbial functional diversity and metabolic shifts is unknown. Here we demonstrate that the availability of trace metals controls electron acceptors utilization in Escherichia coli. Physiological and proteomic data show that trace metals depleted cultures have significantly reduced growth, start fermentation and increase energy expenditure for metal homeostasis even when more energetically favourable electron acceptors are present. Overall these results suggest how evolutionary and competitive pressures arising from changes in biological trace metals availability in deep time have contributed to shaping evolution and competition.

microbiology↗

bioRxiv2022

Sporulation efficiency and spore quality in a human intestinal isolate of Bacillus cereus

The Bacillus cereus group is a species complex of the Bacillus genus that includes several closely related species. Within this group, bacteria indicated as B. cereus sensu stricto (B. cereus) are the causative agent of two different types of gastrointestinal diseases associated with food poisoning. Outbreaks of this opportunistic pathogen are generally due to the resistance of its spores to heat, pH and desiccation that makes hard their complete inactivation from food products. B. cereus is commonly isolated from a variety of environments, including intestinal samples of infected and healthy people. We report the genomic and physiological characterization of MV19, a human intestinal strain closely related (ANI value of 98.81%) to the reference strain B. cereus ATCC 14579. MV19 cells were able to grow in a range of temperatures between 20 and 44{degrees}C. At the optimal temperature the sporulation process was induced very rapidly and mature spores efficiently released, however these appeared structurally and morphologically defective. At the sub-optimal growth temperature of 25{degrees}C sporulation was slow and less efficient but a high total number of fully functional spores was produced. Altogether, results reported here indicate that the reduced rapidity and efficiency of sporulation at 25{degrees}C are compensated by a high quality and quantity of released spores, suggesting the relevance of different performances at different growth conditions for the adaptation of this bacterium to diverse environmental niches.

microbiology↗

bioRxiv2021

Genomic Mining and Physiological Characterization of new Halophilic Plant Growth Promoting Bacilli

Massive application of chemical fertilizers and pesticides has been the main strategy used to cope with the rising crop demands in the last decades. The indiscriminate use of chemicals while providing a temporary solution to food demand has led to a decrease in crop productivity and an increase in the environmental impact of modern agriculture. A sustainable alternative to the use of chemicals for crop production is the use of microorganisms naturally capable of enhancing plant growth and protecting crops from pests, known as Plant-Growth-Promoting Bacteria (PGPB). Aim of the present study was to isolate and characterize PGPB from salt-pans sand samples able to ameliorate plant fitness. To survive high salinity, salt-tolerant microbes produce a broad range of compounds with heterogeneous biological activities that are potentially beneficial for plant growth. We have isolated and screened in vitro a total of 20 halophilic spore-forming bacteria for phyto-beneficial traits and compared the results with two Bacilli recently isolated from the rhizosphere of the same collection site and recently characterized as potential biocontrol agents. Whole-genome analysis on five selected halophilic strains confirmed the presence of numerous gene clusters with PGP and biocontrol functions and of novel secondary-metabolite biosynthetic genes potentially involved in plant growth promotion and protection. The predicted biocontrol potential was confirmed in dual culture assays against several phytopathogenic fungi and bacteria. Interestingly, the absence of predicted gene clusters with known biocontrol functions in some of the isolates was not predictive of the in vitro results, supporting the need of combining laboratory assays and genome mining in PGPB identification for future applications.

microbiology↗

bioRxiv2018

A protein phosphorylation module patterns the Bacillus subtilis spore outer coat

Assembly of the Bacillus subtilis spore coat involves over 80 protein components, which self-organize into a basal layer, a lamellar inner coat, a striated electrondense outer coat and a more external crust. CotB is an abundant component of the outer coat. Its C-terminal moiety contains a region, termed SKRB, formed by a series of serine-rich repeats, which we show is phosphorylated by the coat-associated Ser/Thr kinase CotH at multiple Ser residues. Another coat protein, CotG, which contains a central repeat region, SKRG, interacts with the C-terminal moiety of CotB and promotes its phosphorylation by CotH in vivo and in a heterologous system. CotG itself is phosphorylated by CotH but phosphorylation is enhanced in the absence of CotB. Spores of a cotHD288A strain, producing an inactive form of the kinase, like those formed by a cotG deletion mutant, lack the characteristic pattern of electrondense outer coat striations, while retaining the crust. Specifically, in the absence of CotG or CotH activity, most of the outer coat proteins are assembled but form a layer of amorphous material that peels-off the spore if crust formation is genetically ablated. In contrast, deletion of the SKRB region, has no major impact on the structure of the outer coat. Thus, phosphorylation of CotG by CotH is the principal factor establishing the structural pattern of the spore outer coat. The presence of the cotB/cotH/cotG cluster in several species closely related to B. subtilis and of cotG-like proteins in nearly all spore-formers that also code for a CotH homologue hints at the importance of this protein phosphorylation module in the morphogenesis of the spore outer layers.

microbiology↗