Biology subjects

Ribeiro, T. H. C.

Publications and source records attributed to Ribeiro, T. H. C..

4 recordsLinked to original sources

bioRxiv2024

The contrasting flowering-time among coffee genotypes is associated with ectopic and differential expressions of genes related to environment, floral development, and hormonal regulation

The molecular pathways underlying floral activation and development are well described in model species, but exhibit significant diversity in plants that is poorly understood in crops with complex cycles, such as Coffea arabica L. The reproductive development of coffee plants is biannual, and the flowering time is crucial for the coffee productivity and cup quality. In this study, we explored the plasticity of floral development and flowering-time of contrasting coffee genotypes to understand the associated metabolic and regulatory transcriptional profiles. Firstly, we compared the reproductive development of three coffee genotypes, confirming that Acaua is late flowering, Oeiras is early flowering, and the natural mutant Semperflorens (Sf) exhibits continuous flowering throughout the year. Analysis of sugar and ethylene content revealed quantitative differences between genotypes in both leaves and floral buds. To associate these phenotypic differences with the regulatory developmental pathways, we performed RNA-seq analysis comparing the shoot apical meristems, floral buds and leaves of different genotypes. Our analysis identified 12.478 differentially expressed genes, which showed enriched terms mainly related to hormonal regulation, external stimulus and floral development. Notably, some major players of reproductive development, as homologs of FLOWERING LOCUS T and MADS-box genes, showed contrasting expression patterns, generally being ectopically upregulated in the Sf mutant. These findings were associated with the phenotypic differences among coffee genotypes. In conclusion, the present study improves the understanding of the divergence of floral development in coffee, providing valuable insights for directing breeding programs and future studies aiming at controlling floral development and enhancing crop production.

plant biology↗

bioRxiv2023

Unveiling the phenology and associated floral regulatory pathways of Humulus lupulus L. in subtropical conditions

The Humulus lupulus L. (hops) is traditionally produced in temperate regions, historically attributed to the belief that vernalization was necessary for reproductive transition. Nevertheless, recent studies have revealed the potential for hop plants to flower in tropical and subtropical climates, thereby reshaping cultivation prospects once the developmental disparities are understood and adapted for optimized production. Here, we delved into the hop phenological cycle and the underlying floral regulatory pathways ultimately, seeking to devise strategies to modulate development and enhance production in regions with low latitudes. In contrast to cultivation in temperate regions, hops grown in the subtropical climate of Minas Gerais, Brazil, flower multiple times throughout the year, independently of the season. Hop is a short-day plant, and in Brazil, the photoperiod is consistently inductive due to daylight hours always being below the described threshold (16,5 h of light critical point). We observed that the reproductive transition of hop initiates after a specific number of nodes, 25 to 28, leading us to hypothesize that this process is primarily controlled by endogenous factors. To explore this issue, we first identified in the hop genome families of miRNAs related to reproductive transition, such as the families MIR156 and MIR172, and the PEBP family which includes the FLOWERING LOCUS T (FT). The expression of miR156 decreased along development inversely to miR172 and in synchrony with the upregulation of HlFT3 and HlFT5. These findings strongly support that the reproductive transition in hops under inductive photoperiodic conditions is primarily regulated by endogenous factors related to development and aging throughout the miRNA and FT-associated pathways. Thus, our study shedded light on the intricate molecular mechanisms that underlie hop floral development paving the way for potential advancements in hop production on a global scale.

plant biology↗

bioRxiv2023

The floral development of the allotetraploid Coffea arabica L. correlates with a small RNA dynamic reprogramming.

O_LINon-coding and coding RNAs are key regulators of plant growth, development, and stress responses. To investigate the types of transcripts accumulated during the vegetative to reproductive transition and floral development in the Coffea arabica L., we sequenced small RNA libraries from eight developmental stages, up to anthesis. C_LIO_LIWe combined this data with messenger RNA and PARE sequencing of two important development stages that marks the transition of an apparent latent to a rapid growth stage. In addition, we took advantage of multiple in silico tools to characterize genomic loci producing small RNAs such as phasiRNAs, miRNAs and tRFs. C_LIO_LIOur differential and co-expression analysis showed that some types of small RNAs such as tRNAs, snoRNAs, snRNAs and phasiRNAs preferentially accumulate in a stage- specific manner. C_LIO_LIMembers of the miR482/miR2118 superfamily and their 21-nucleotide phasiRNAs originating from resistance genes show a robust co-expression pattern that is maintained across all the evaluated developmental stages. Finally, the majority of miRNAs accumulate in a family-stage specific manner, related to modulated hormonal responses and transcription factors expression. C_LI Societal Impact StatementThis research holds potential to benefit millions of coffee-producing families in over 60 countries. We uncovered molecular regulatory mechanisms governing flower development, one of the causes for the Coffea arabicas uneven ripening. The absence of uniformity in coffee production, spanning from floral induction to branch senescence, has a detrimental impact on the final products quality. These insights will inform strategies for controlled coffee maturation, leading to improved, uniform harvests.

plant biology↗

bioRxiv2020

Elevated temperatures impose transcriptional constraints on coffee genotypes and elicit intraspecific differences in thermoregulation

The projected impact of global warming on coffee production may require the heat-adapted genotypes in the next decades. To identify thermotolerance cellular strategies, we compared the effect of elevated temperature on two commercial Coffea arabica L. genotypes exploring leaf physiology, transcriptome and carbohydrate/protein composition. Growth temperatures were 23/19{degrees}C (day/night), as optimal condition (OpT), and 30/26{degrees}C (day/night) as a possible warmer scenario (WaT). The cv. Acaua showed lower levels of leaf temperature under both conditions compared to cv. Catuai, whereas slightly or no differences for other leaf physiological parameters. Therefore, to explore thermoregulatory pathways the leaf transcriptome was examined using RNAseq. Genotypes showed a marked number of differentially-expressed genes (DEGs) under OpT, however DEGs strongly decrease in both at WaT condition indicating a transcriptional constraint. DEGs responsive to WaT revealed shared and genotype-specific genes mostly related to carbohydrate metabolism. Under OpT, leaf starch content was greater in cv. Acaua although the levels of leaf starch, sucrose, and leaf protein decreased in both genotypes as WaT was imposed. These findings indicate that genotypes with a greater capacity to maintain carbohydrate homeostasis under temperature fluctuations could be more thermotolerant and which may be useful in breeding for a changing climate. HIGHLIGHTIn response to warming, transcriptional differences decrease in coffee genotypes hampering breeding programs. Differences in gene expression and sugar levels confirm intraspecific variation associating thermotolerance to maintenance of energetic homeostasis.

plant biology↗