Search bioRxiv⌕ Search

Biology subjects

Bonatelli, M. L.

Publications and source records attributed to Bonatelli, M. L..

5 recordsLinked to original sources

Molecular and phenotypic footprints of climate in native Arabidopsis thaliana

Climate change poses a major threat to humanity by driving biodiversity loss and reducing crop yields1,2. To understand the molecular and developmental impacts of rising temperatures, plant science has relied heavily on the model organism Arabidopsis thaliana. Despite decades of research, its development under fully natural conditions remains poorly understood, and only [~]30% of genes have experimental functional annotations, largely because many functions are subtle or manifest only in specific laboratory or ecological contexts3. Here, we address this gap with a landscape transcriptomic approach that integrates intensive phenotyping and transcriptomic profiling of naturally occurring plants in their native habitats4. Across two contrasting field sites and five growing seasons (2021-2025), we phenotyped more than 3,000 A. thaliana plants and generated >1,600 matching transcriptomes. The resulting >30,000 quantitative trait measurements provide a unique opportunity to link climate fluctuations with plant traits and gene expression. Seasons characterized by extreme temperature anomalies directly influenced plant traits, and climatic variables together explained up to 17% of phenotypic variation. In situ transcriptomes carried clear temperature and local environmental signatures, closely matching temperature-response programs known from the laboratory. Leveraging paired per-plant transcriptomes and phenotypes, we applied machine learning to predict regulators of climate-relevant and other plant traits under natural conditions. The models recovered canonical thermomorphogenesis regulators, including PHYTOCHROME INTERACTING FACTOR 4 (PIF4)5,6, providing ecological evidence that temperature signaling pathways defined in controlled environments operate in the wild, and expanded this regulatory landscape by identifying hormonal receptors, signaling components, and previously uncharacterized genes, some of which we functionally validated. Together, this work demonstrates that landscape transcriptomics, by integrating natural field transcriptomes with phenotypes, and thus, capturing environmental and regulatory states, enables the predictive identification of genetic regulators of temperature responses and broader plant traits. This makes landscape transcriptomics a scalable framework for climate-aware functional genomics in plants.

plant biology↗

Reduced carbon emissions and chain elongation during mixotrophic fermentation of a biomass feedstock

Anaerobic fermentation of biomass feedstocks using open cultures is a promising technology to produce platform carboxylates. Syngas, a mixture of H2, CO2, and CO, can be sourced sustainably and used to supplement biomass feedstocks as a source of acetyl-CoA, an intermediate for carboxylate chain elongation. To test this, syngas and corn silage were provided to a 10-L semi-continuous fermenter for 209 days of operation in a first-of-a-kind study at this scale. After acclimation to syngas, a two-fold reduction in average CO2 production rate (0.097 vs. 0.21 g L-1d-1) was observed over a period of 42 days in comparison to a control. Syngas co-feeding also increased average production rates of n-butyrate (C4) and n-caproate (C6) by 74% and 27%, respectively, although these effects were observed at relatively low C6 concentrations up to 4 g L-1. Relative abundances of Megasphaera and Dialister showed significant correlation (p<0.05) to consumption of H2 and CO as well as production of C4 and C6, suggesting involvement of these genera in mixotrophic metabolism. A feasibility analysis showed that syngas recirculation could return additional 1.54 USD m-3broth while costing 1.26 USD m-3broth and avoiding 1.81 kg CO2 eq. m-3broth in emissions compared to heterotrophic fermentation. We propose mixotrophic fermentation as a low-tech technology to turn fermenters into decentralized industrial carbon sinks. SYNOPSISFermentation of biomass and syngas could be used for sustainable and circular chemical production. This study tested the feasibility of this technology and identified relevant process parameters and microbial genera.

bioengineering↗

A novel sulfatase for acesulfame degradation in wastewater treatment plants as evidenced from Shinella strains

The artificial sweetener acesulfame is a persistent pollutant in wastewater worldwide. So far, only a few bacterial isolates were recently found to degrade acesulfame efficiently. In Bosea and Chelatococcus strains, a Mn2+-dependent metallo-{beta}-lactamase-type sulfatase and an amidase signature family enzyme catalyze acesulfame hydrolysis via acetoacetamide-N-sulfonate (ANSA) to acetoacetate. Here, we describe a new acesulfame sulfatase in Shinella strains isolated from German wastewater treatment plants. Their genomes do not encode the Mn2+-dependent sulfatase. Instead, a formylglycine-dependent sulfatase gene was found, together with the ANSA amidase gene on a plasmid shared by all known acesulfame-degrading Shinella strains. Heterologous expression, shotgun proteomics and size exclusion chromatography corroborated the physiological function of the Shinella enzyme as a Mn2+-independent acesulfame sulfatase. Since both the Bosea/Chelatococcus sulfatase and the novel Shinella sulfatase are absent in other bacterial genomes or metagenome assembled genomes, we surveyed 60 tera base pairs of wastewater-associated metagenome raw datasets. The Bosea/Chelatococcus sulfatase gene was regularly found from 2014 on, particularly in North America, Europe and East Asia, whereas the Shinella sulfatase gene was first detected in 2020. The complete Shinella pathway is only present in five datasets from China, Finland and Mexico, suggesting that it emerged quite recently in wastewater treatment facilities. SynopsisA novel sulfatase was identified that hydrolyzes the once recalcitrant xenobiotic acesulfame. Surveying metagenome datasets revealed the recent emergence of gene homologs encoding this sulfatase in wastewater treatment systems worldwide.

genomics↗

Recently evolved combination of unique sulfatase and amidase genes enables bacterial degradation of the wastewater micropollutant acesulfame worldwide

Xenobiotics often challenge the principle of microbial infallibility. One example is acesulfame introduced in the 1980s as zero-calorie sweetener, which was recalcitrant in wastewater treatment plants until the early 2010s. Then, efficient removal has been reported with increasing frequency. By studying acesulfame metabolism in alphaproteobacterial degraders of the genera Bosea and Chelatococcus, we experimentally confirmed the previously postulated route of two subsequent hydrolysis steps via acetoacetamide-N-sulfonate (ANSA) to acetoacetate and sulfamate. Genome comparison of wildtype Bosea sp. 100-5 and a spontaneous acesulfame degradation-defective mutant revealed the involvement of two plasmid-borne gene clusters. The acesulfame-hydrolyzing sulfatase is strictly manganese-dependent and belongs to the metallo beta-lactamase family. In all degraders analyzed, it is encoded on a highly conserved gene cluster embedded in a composite transposon. The ANSA hydrolase, on the other hand, is an amidase signature domain enzyme encoded in another gene cluster showing variable length among degrading strains. Transposition of the sulfatase gene cluster between chromosome and plasmid explains how the two catabolic gene clusters recently combined for the degradation of acesulfame. Searching available genomes and metagenomes for the two hydrolases and associated genes indicates that the acesulfame plasmid evolved and spread worldwide in short time. While the sulfatase is unprecedented and unique for acesulfame degraders, the amidase occurs in different genetic environments and might have evolved for the degradation of other substrates. Evolution of the acesulfame degradation pathway might have been supported by the presence of structurally related natural and anthropogenic compounds, such as aminoacyl sulfamate ribonucleotide or sulfonamide antibiotics.

microbiology↗

Bacillus sp. RZ2MS9, a tropical PGPR, colonizes maize endophytically and alters the plant's production of volatile organic compounds both independently and when co-inoculated with Azospirillum brasilense Ab-V5

Bacillus spp. are among the most efficient known plant growth-promoting rhizobacteria (PGPR). The PGPR Bacillus sp. strain RZ2MS9 is a multi-trait maize growth promoter previously isolated from guarana plants cultivated in the Amazon rainforest. However, there are several aspects of its interaction with the host that need further investigation. To achieve effective performance of microbial inoculants in crop production, it is necessary to monitor the plants colonization by a PGPR and to assess the potential synergy among beneficial strains. Here, we obtained a stable mutant of RZ2MS9 labelled with green fluorescent protein (RZ2MS9-GFP). We verified that the insertion of the plasmid did not affect either bacterial growth nor its ability to promote maize growth in vitro. Using fluorescent microscopy and qPCR, we demonstrated that RZ2MS9-GFP successfully colonizes maizes roots and leaves endophytically. Subsequently, we evaluated whether RZ2MS9 has a synergistic effect on plant growth promotion when co-inoculated with Azospirillum brasilense Ab-V5, a commercial inoculant for maize. The two strains combined enhanced maizes roots and shoots dry weight by 50.8% and 79.6%, respectively, when compared to the non-inoculated control. In addition, we used co-inoculation experiments in glass chambers to analyze the plants Volatile Organic Compounds (VOCs) production during the maize-RZ2MS9 and maize-RZ2MS9-Ab-V5 interaction. We found that the single and co-inoculation altered maizes VOCs emission profile, with an increase in the production of indoles in the co-inoculation. Collectively, these results increase our knowledge about the interaction between the tropical PGPR Bacillus sp. RZ2MS9 and maize, and provide a new possibility of combined application with the commercial inoculant A. brasilense Ab-V5. ImportanceBacillus sp. RZ2MS9 is a PGPR, previously isolated from guarana plants cultivated in the Brazilian Amazon, which successfully promotes the growth of maize and soybean plants. To improve our knowledge about the interaction between this very promising PGPR and maize, we labelled RZ2MS9 with gfp and monitored its maize colonization. The transformation did not affect either RZ2MS9 growth nor its ability to promote maize growth in vitro. We demonstrated that RZ2MS9 colonizes endophytically maizes roots and leaves. We also verified that the co-inoculation of RZ2MS9 and Azospirillum brasilense Ab-V5, a known commercial maize inoculant enhanced maizes roots and shoots growth. Moreover, the co-inoculation altered the maizes volatile organic compounds, increasing the production of indoles, that is related with decreased upon the reduction of fertilization. Certainly, our research contributed with better Bacillus sp. RZ2MS9 - maize interaction understanding and also provided new information concerning RZ2MS9 activity when applied with A. brasilense Ab-V5.

molecular biology↗