Biology subjects

Garcia, J. E.

Publications and source records attributed to Garcia, J. E..

4 recordsLinked to original sources

bioRxiv2026

Protein-independent regulation by transgene-derived small interfering RNAs rewires endogenous regulatory networks to enhance plant growth, architecture, and drought performance

Plants produce diverse small interfering RNA (siRNA) molecules that modulate development, environmental responses, and immunity. Although transgene-derived siRNAs are traditionally viewed as mediators of gene silencing, whether they can actively regulate endogenous host pathways remains largely unexplored. Previously obtained Arabidopsis, wheat, and soybean plants expressing the sunflower gene encoding the transcription factor HaHB4 exhibited water deficit tolerance. Here, we show that expressing inverted-repeat constructs that generate HaHB4-derived siRNAs without producing the HaHB4 protein bypasses transgenic growth penalties and instead enhances vegetative vigor and reproductive performance. In Arabidopsis, these DCL-dependent siRNA-producing lines exhibited enhanced root growth, increased stem and pith areas, increased cauline branching, and higher seed yield under both optimal and water-limiting conditions. Transcriptomic analysis revealed convergent repression of biotic stress-related genes, accompanied by increased bacterial susceptibility and reduced sensitivity to salicylic acid-mediated growth inhibition, suggesting an altered balance between immunity and growth. Functional characterization of candidate endogenous HD-Zip I targets further showed that athb20 and athb53 mutants recapitulated the increased stem expansion and cauline branching of the RNAi lines, respectively, pointing to endogenous HD-Zip I genes as candidate mediators of these traits. Remarkably, these effects were observed in newly obtained transgenic soybean plants, where expression of HaHB4-derived siRNAs enhanced vegetative vigor under controlled growth conditions. Overall, these findings show that transgene-derived siRNAs act independently of protein function to rewire endogenous regulatory networks, providing a potential strategy to optimize crop architecture and yield.

plant biology↗

bioRxiv2026

Effects of predictability and error on corticospinal excitability during an electronic prediction game

Background: Detecting environmental regularities is a sophisticated cognitive skill, but its neural basis remains unclear. We tested whether corticospinal excitability tracks stimulus predictability, prediction errors, and task progression while the participants played the Goalkeeper Game. Methods: Sixteen right-handed males (24.4 +/- 6.8 years) saved penalty kicks using index, middle, or ring fingers (left, center, right). Kick sequences were generated by a context tree model, in which contexts represent the minimum recent history required to predict the next event. Participants completed 1,200 trials (6 blocks x 200 trials each). Transcranial magnetic stimulation (TMS) delivered 400 ms before the go signal elicited motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) and flexor digitorum superficialis (FDS) muscles during blocks 2, 4, and 6. Contexts were classified as unpredictable (1, 10) or predictable (2, 20, 00); prediction errors were defined for non-deterministic transitions after context 1. Log-MEPs were analyzed using mixed-effects models. Results: In FDI, a Predictability x Previous-Error x Block interaction emerged (F(2,8997)=6.89, p=.001), confined to the final block. Predictability increased MEP amplitudes after successful transitions (+6.3%; p=0.006) but decreased MEP amplitudes after failed transitions (-7.0%; p=0.007). For FDS, unpredictable trials elicited larger MEPs (+7.2%; p=0.002), and MEPs increased from block 2 to 6 (+16.8%; p=0.003). Conclusions: FDS MEP responses were broadly associated with uncertainty and task progression, whereas FDI MEP responses showed context-specific, error-dependent modulation after extended exposure, suggesting fine-grained predictive coding in goal-executing effectors.

neuroscience↗

bioRxiv2019

Australian native flower colours: does nectar reward drive bee pollinator flower preferences?

Colour is an important signal that flowering plants use to attract insect pollinators like bees. Previous research in Germany has shown that nectar volume is higher for flower colours that are innately preferred by European bees, suggesting an important link between colour signals, bee preferences and floral rewards. In Australia, flower colour signals have evolved in parallel to the Northern hemisphere to enable easy discrimination and detection by the phylogenetically ancient trichromatic visual system of bees, and native Australian bees also possess similar innate colour preferences to European bees. We measured 59 spectral signatures from flowers present at two preserved native habitats in South Eastern Australia and tested whether there were any significant differences in the frequency of flowers presenting higher nectar rewards depending upon the colour category of the flower signals, as perceived by bees. We also tested if there was a significant correlation between chromatic contrast and the frequency of flowers presenting higher nectar rewards. For the entire sample, and for subsets excluding species in the Asteraceae and Orchidaceae, we found no significant difference among colour categories in the frequency of high nectar reward. This suggests that whilst such relationships between flower colour signals and nectar volume rewards have been observed at a field site in Germany, the effect is likely to be specific at a community level rather than a broad general principle that has resulted in the common signalling of bee flower colours around the world.

ecology↗

bioRxiv2019

Alarm tones, music and their elements: A mixed methods analysis of reported waking sounds for the prevention of sleep inertia.

Sleep inertia is a potentially dangerous reduction in human alertness and occurs 0 - 4 hours after waking. The type of sound people set as their alarm for waking has been shown to reduce the effects of sleep inertia, however, the elemental musical factors that underpin these waking sounds and their relationship remain unclear. The goal of this research is to understand how a particular sound or music chosen to assist waking may counteract sleep inertia, and more specifically, what elements of these sounds may contribute to its reduction using a mix methods analysis. Through an anonymous, self-report online questionnaire, fifty participants (N = 50) reported attributes of their preferred waking sound, their feeling towards the waking sound, and symptoms of sleep inertia after waking. This data enabled the analysis and comparison between these responses to define statistically significant interactions. Our results show that there is no significant relationship between sleep inertia and the reported waking sound, nor the subjects feeling towards this sound. However, we found that the melodicity of a chosen waking sound does effect sleep inertia. A sound that is perceived as melodic, produces less sleep inertia in comparison to a sound considered to be neutral (neither unmelodic nor melodic). Furthermore, a secondary analysis reveals that this is an important factor for waking stimulus design as it suggests that the amount of perceived rhythm will affect the perception of melody, and in turn, may influence the severity of sleep inertia on a secondary level. Our results reveal that the inclusion of detailed descriptive terms (musical elements) in addition to macro classifications (e.g. \"pop music\") for stimulus testing would benefit future research and our understanding of waking audios effects on sleep inertia.

animal behavior and cognition↗