• Research softwareclose
• Other research productsclose
• 2019-2023close
• BE close
• Ghent University Academic Bibliography close

A large part of a plants’ developmental plasticity relies on the activities of the phytohormone auxin and the regulation of its own distribution. This process involves a cohort of transcriptional and non-transcriptional effects of auxin on polar auxin transport, regulating the abundancy, biochemical activity and polar localization of the molecular components, predominantly PIN auxin exporters. While the transcriptional auxin signaling cascade has been well characterized, the mechanism and role of non-transcriptional auxin signaling remains largely elusive. Here, we addressed the potential involvement of auxin-induced Ca2+ signaling in auxin’s inhibitory effect on PIN endocytic trafficking. On the one hand, exogenous manipulations of Ca2+ availability and signaling effectively antagonized auxin effects suggesting that auxin-induced Ca2+ signaling is required for inhibition of internalization. On the other hand, we addressed the auxin-mediated inhibition of PIN internalization in the auxin signaling (tir1afb2,3) or Ca2+ channel (cngc14) mutants. These mutants were strongly defective in auxin-triggered Ca2+ signaling, but not in auxin-inhibited internalization. These data imply that, while Ca2+ signaling may be required for normal PIN trafficking, auxin-mediated increase in Ca2+ signaling is not a direct part of a downstream mechanism that mediates auxin effects on Brefeldin A-visualized PIN intercellular aggregation. These contrasting results obtained by comparing the mutant analysis versus the exogenous manipulations of Ca2+ availability and signaling illustrate the critical importance of genetics to unravel the role of Ca2+ in a process of interest.

Let R be a polynomial ring over a field and I⊂R be a Gorenstein ideal of height three that is minimally generated by homogeneous polynomials of the same degree. We compute the multiplicity of the saturated special fiber ring of I. The obtained formula depends only on the number of variables of R, the minimal number of generators of I, and the degree of the syzygies of I. Applying results from arXiv:1805.05180, we get a formula for the j-multiplicity of I and an effective method to study a rational map determined by a minimal set of generators of I.

The Ecuadorian Constitutional Court published its judgment in the case of the Los Cedros forest, a protected cloud forest of great biodiversity in the Andean mountains of Ecuador. This judgment revokes environmental permits previously granted to two mining concessions in the Bosque Protector Los Cedros reserve. The Court ruled that the mining permits in question had not only violated several constitutional rights of communities in the area but also – most remarkably – the rights of mother nature (Pacha Mama). It specifically granted these rights to the Los Cedros Reserve. While the judgment has received international recognition, there is still some uncertainty regarding future applications of this unusual, non-anthropocentric legal standard set by the Court to protect the rights of mother nature.