Biology subjects

Ferreira, S. S.

Publications and source records attributed to Ferreira, S. S..

6 recordsLinked to original sources

bioRxiv2024

Early changes in microRNA expression in Arabidopsis plants infected with the fungal pathogen Fusarium graminearum

Plants respond to biotic stressors by modulating various processes in an attempt to limit the attack by a pathogen or herbivore. Triggering these different defense processes requires orchestration of a network of proteins and RNA molecules that includes microRNAs (miRNAs). These short RNA molecules (20-22 nucleotides) have been shown to be important players in the early responses of plants to stresses because they can rapidly regulate the expression levels of a network of downstream genes. The ascomycete Fusarium graminearum is an important fungal pathogen that causes significant losses in cereal crops worldwide. Using the well-characterized Fusarium-Arabidopsis pathosystem, we investigated how plants change expression of their miRNAs globally during the early stages of infection by F. graminearum. In addition to miRNAs that have been previously implicated in stress responses, we have also identified evolutionarily young miRNAs whose levels change significantly in response to fungal infection. Some of these young miRNAs have homologs present in cereals. Thus, manipulating expression of these miRNAs may provide a unique path toward development of plants with increased resistance to fungal pathogens.

plant biology↗

bioRxiv2024

Genetically encoded Boolean logic operators to sense and integrate phenylpropanoid metabolite levels in plants

O_LISynthetic biology has the potential to revolutionize biotechnology, public health and agriculture. Recent studies have shown the enormous potential of plants as chassis for synthetic biology applications. However, tools to precisely manipulate metabolic pathways for bioproduction in plants are still needed. C_LIO_LIWe have adapted bacterial allosteric transcription factors (aTFs) to control gene expression in plants in a ligand-specific manner. The aTFs used here function as transcription repressors of semi-synthetic promoters, and aTF activity is regulated by specific plant metabolites, especially phenylpropanoid-related molecules. Using these aTFs, we also designed synthetic genetic circuits capable of computing Boolean logic operations. C_LIO_LIThree aTFs, CouR, FapR and TtgR, were able to achieve [~]95% repression of their respective target promoters. For TtgR, a 6-fold de-repression could be triggered by inducing its ligand (naringenin) accumulation, showing its use as biosensor. Moreover, we designed synthetic genetic circuits that use AND, NAND, IMPLY and NIMPLY Boolean logic operations and integrate metabolite levels as input to the circuit. C_LIO_LIWe showed that biosensors can be implemented in plants to detect phenylpropanoid-related metabolites and activate a genetic circuit that follows a pre-defined logic, demonstrating their potential as tools for exerting control over plant metabolic pathways and facilitating the bioproduction of natural products. C_LI

plant biology↗

bioRxiv2023

Fecal Virome of Coendou spinosus (Paraguaian Hairy Dwarf Porcupine)

The porcupine (Coendou spinosus) is a rodent species widely distributed in the Brazilian Atlantic forest. Like other rodent species, porcupines can be potential reservoirs of zoonotic agents. However, little is known about the viral diversity in these animals. Therefore, the objective of the present study was to evaluate, through massive sequencing, the virome of the feces of seven adult healthy free-living porcupines living in forest fragments from Silva Jardim, State of Rio de Janeiro, Brazil. A total of 41 viral families were classified, of which only seven were validated by both Kraken2 and Diamond taxonomic analysis tools, including bacteriophages (Siphoviridae, Myoviridae, Podoviridae), vertebrate viruses, such as Papillomaviridae, and unclassified RNA viruses. In addition, we also observed the presence of pathogenic bacteria and fungi already described in porcupines. The present study describes for the first time the microbiome in fecal samples from Brazilian porcupines, contributing to the global metagenomic characterization.

microbiology↗

bioRxiv2023

Fecal Virome of Southeastern Maned Sloth (Bradypus crinitus)

We report a viral metagenomic analysis of fecal samples from Bradypus crinitus, a recently described sloth species that occurs in the Atlantic Forest of Espirito Santo and Rio de Janeiro states, Southeast Brazil. Through Illumina sequencing, we generated a total of 2,065,344 raw reads, of which 945,386 reads (45.77%) passed the quality and size filter. The highest proportion of them was assigned to Eukarya, followed by Bacteria and only a small proportion to Virus. However, we identified 24 viral families using distinct taxonomic assignment tools, including phages and vertebrate viruses, such as retroviruses and papillomaviruses. Also, we identified four bacterial genus already associated with disease in sloths. Our study sheds light on the microbiome of a previously unexplored species, further contributing to the comprehension of metagenomic global diversity.

genetics↗

bioRxiv2022

Metagenomic analysis reveals novel dietary-related viruses in the gut virome of marmosets hybrids (Callithrix jacchus x Callithrix penicillata), Brazil

Viral metagenomics has contributed enormously to the characterization of a wide range of viruses infecting animals of all phyla in the last decades. Among Neotropical primates, especially those free-living introduced, knowledge about viral diversity remains poorly studied. Therefore, through the use of metagenomics based on virus enrichment, we explored the viral microbiota present in the feces of introduced common marmosets (Callithrix sp.) in three locations from the Silva Jardim region in the State of Rio de Janeiro, Brazil. Fecal samples were collected from nine marmosets, pooled into three sample pools and sequenced on Illumina MiSeq platform. Sequence reads were analyzed using a viral metagenomic analysis pipeline and two novel insect viruses belonging to the Parvoviridae and Baculoviridae families were identified. The complete genome of a densovirus (Parvoviridae family) of 5,309 nucleotides (nt) was obtained. The NS1 and VP1 proteins share lower than 32% sequence identity with the corresponding proteins of known members of the subfamily Densovirinae. Phylogenetic analysis suggests that this virus represents a new genus, named Tritonambidensovirus due to telomeric structures at the 3 and 5 ends of the genome. The novel species received the name Fecalis tritonambidensovirus 1. The complete circular genome of a baculovirus of 107,191 nt was also obtained, showing 60.8% sequence identity with the most closely related member of the Baculoviridae family. Phylogenetic analysis suggests that this virus represents a new species of Betabaculovirus, named Callithrix fecalis granulovirus. In addition, sequences from several families of arthropods in the three pools evaluated were characterized (contigs ranging from 244 to 6,750 nt), corroborating the presence of possible insect hosts with which these new viruses may be associated. Our study expands the knowledge about two viral families known to infect insects, an important component of the marmosets diet. This identification in hosts feces samples demonstrates one of the many uses of this type of data and could serve as a basis for future research characterizing viruses in wildlife using noninvasive samples.

genomics↗

bioRxiv2019

Structural and functional analysis of genes with potential involvement in resistance to coffee leaf rust: a functional marker based approach

Physiology-based differentiation of SH genes and Hemileia vastatrix races is the principal method employed for the characterization of coffee leaf rust resistance. Based on the gene-for-gene theory, nine major rust resistance genes (SH1-9) have been proposed. However, these genes have not been characterized at the molecular level. Consequently, the lack of molecular data regarding rust resistance genes or candidates is a major bottleneck in coffee breeding. To address this issue, we screened a BAC library with resistance gene analogs (RGAs), identified RGAs, characterized and explored for any SH related candidate genes. Herein, we report the identification and characterization of a gene (gene 11), which shares conserved sequences with other SH genes and displays a characteristic polymorphic allele conferring different resistance phenotypes. Furthermore, comparative analysis of the two RGAs belonging to CC-NBS-LRR revealed more intense diversifying selection in tomato and grape genomes than in coffee. For the first time, the present study has unveiled novel insights into the molecular nature of the SH genes, thereby opening new avenues for coffee rust resistance molecular breeding. The characterized candidate RGA is of particular importance for further biological function analysis in coffee.

pathology↗