Biology subjects

Pacheco, R.

Publications and source records attributed to Pacheco, R..

4 recordsLinked to original sources

bioRxiv2026

Calreticulin modulates the infection process and nodule organogenesis in the Phaseolus vulgaris-Rhizobium symbiosis

Calreticulins are multifunctional proteins involved in calcium homeostasis, protein folding, and cellular signaling. In common bean (Phaseolus vulgaris), the molecular mechanisms that regulate infection and nodule development remain incompletely understood. The main objective of this study was to characterize the role of the calreticulin gene PvCRT08 during infection and nodulation processes. We first analyzed the calreticulin gene family in the P. vulgaris genome and identified three members, with PvCRT08 showing the highest transcript accumulation in roots and after inoculation with rhizobia. Spatial and temporal promoter analyses in transgenic composite bean roots revealed PvCRT08 activity in root hairs and in infected cells and vascular bundles of mature nodules. RNA interference (RNAi)-mediated PvCRT08 down-regulation in transgenic roots increased the number of infection threads and enhanced nitrogen fixation efficiency, leading to the formation of larger and more functional nodules, although total nodule number was unaffected. In contrast, overexpression of PvCRT08 impaired infection thread progression, reduced the expression of key nodulation marker genes (PvCyclin and PvNIN), decreased nodule number, and diminished nitrogen fixation capacity. These findings identify PvCRT08 as a key regulatory component of early infection events and nodule development in common bean. Furthermore, the study provides new insights into the molecular control of symbiotic efficiency and highlights PvCRT08 expression is critical to optimize the equilibrium between infection efficiency and nodule functionality.

plant biology↗

bioRxiv2024

The non-specific phospholipase C of common bean PvNPC4 modulates roots and nodule development

Plant phospholipase C (PLC) proteins are phospholipid-degrading enzymes classified into two subfamilies: phosphoinositide-specific PLCs (PI-PLCs) and non-specific PLCs (NPCs). PI-PLCs have been widely studied in various biological contexts, including responses to abiotic and biotic stresses and plant development; NPCs have been less thoroughly studied. No PLC subfamily has been characterized in relation to the symbiotic interaction between Fabaceae (legume) species and the nitrogen-fixing bacteria called rhizobia. However, lipids are reported to be crucial to this interaction, and PLCs may therefore contribute to regulating legume-rhizobia symbiosis. In this work, we functionally characterized NPC4 from common bean (Phaseolus vulgaris L.) during rhizobial symbiosis, finding evidence that NPC4 plays an important role in bean root development. The knockdown of PvNPC4 by RNA interference (RNAi) resulted in fewer and shorter primary roots and fewer lateral roots than were seen in control plants. Importantly, this phenotype seems to be related to altered auxin signaling. In the bean-rhizobia symbiosis, PvNPC4 transcript abundance increased 3 days after inoculation with Rhizobium tropici. Moreover, the number of infection threads and nodules, as well as the transcript abundance of PvEnod40, a regulatory gene of early stages of symbiosis, decreased in PvNPC4-RNAi roots. Additionally, transcript abundance of genes involved in autoregulation of nodulation (AON) was altered by PvNPC4 silencing. These results indicate that PvNPC4 is a key regulator of root and nodule development, underscoring the participation of PLC in rhizobial symbiosis.

plant biology↗

bioRxiv2024

Inhibition of Fusarium oxysporum growth in banana by silver nanoparticles: in vitro and in vivo assays

Fusarium wilt is a devastating disease that affects banana crops worldwide. In Ecuador, bananas are one of the most important commodities and staple food. Nanoparticles are emerging as innovative solutions to control fungal diseases in plant protection. In this study, in vitro and in vivo assays were carried out to validate Fusarium oxysporum growth and disease inhibition. 96-well plates experiments were used to calculate the IC50 of three different silver nanoparticle formulations (Argovit-1220, Argovit-1221, and Argovit-C) against four Ecuadorian Fusarium strains (EC15-E-GM1, EC19-LR-GM3, EC35-G-GM6, EC40-M-GM2). More than 95% inhibition rate was obtained at 25 mg L-1 concentration. Fusarium wilt in vivo assay was carried out with Gros Michel plants, where better control was obtained by applying silver nanoparticles to the roots, reducing disease development by an average of 68%. This study shows that silver nanoparticles have a high antifungal potential for controlling the Fusarium wilt of bananas. To the best of our knowledge, this is the first study to test the potential of silver nanoparticles against Fusarium oxysporum in planta under greenhouse conditions.

microbiology↗

bioRxiv2024

Negative allosteric modulation of cannabinoid CB1 receptor signaling suppresses opioid-mediated tolerance and withdrawal without blocking opioid antinociception

The direct blockade of CB1 cannabinoid receptors produces therapeutic effects as well as adverse side-effects that limit their clinical potential. CB1 negative allosteric modulators (NAMs) represent an indirect approach to decrease the affinity and/or efficacy of orthosteric cannabinoid ligands or endocannabinoids at CB1. We recently reported that GAT358, a CB1-NAM, blocked opioid-induced mesocorticolimbic dopamine release and reward via a CB1-allosteric mechanism of action. Whether a CB1-NAM dampens opioid-mediated therapeutic effects such as analgesia or alters other unwanted side-effects of opioids remain unknown. Here, we characterized the effects of GAT358 on nociceptive behaviors in the presence and absence of morphine. We examined the impact of GAT358 on formalin-evoked pain behavior and Fos protein expression, a marker of neuronal activation, in the lumbar dorsal horn. We also assessed the impact of GAT358 on morphine-induced slowing of colonic transit, tolerance, and withdrawal behaviors. GAT358 attenuated morphine antinociceptive tolerance without blocking acute antinociception. GAT358 also reduced morphine-induced slowing of colonic motility without impacting fecal boli production. GAT358 produced antinociception in the presence and absence of morphine in the formalin model of inflammatory nociception and reduced the number of formalin-evoked Fos protein-like immunoreactive cells in the lumbar spinal dorsal horn. Finally, GAT358 mitigated the somatic signs of naloxone-precipitated, but not spontaneous, opioid withdrawal following chronic morphine dosing in mice. Our results support the therapeutic potential of CB1-NAMs as novel drug candidates aimed at preserving opioid-mediated analgesia while preventing their unwanted side-effects. Our studies also uncover previously unrecognized antinociceptive properties associated with an arrestin-biased CB1-NAMs. HighlightsO_LICB1 negative allosteric modulator (NAM) GAT358 attenuated morphine tolerance C_LIO_LIGAT358 reduced morphine-induced slowing of colonic motility but not fecal production C_LIO_LIGAT358 was antinociceptive for formalin pain alone and when combined with morphine C_LIO_LIGAT358 reduced formalin-evoked Fos protein expression in the lumbar spinal cord C_LIO_LIGAT358 mitigated naloxone precipitated withdrawal after chronic morphine dosing C_LI

neuroscience↗