Biology subjects

Cleard, F.

Publications and source records attributed to Cleard, F..

3 recordsLinked to original sources

bioRxiv2024

Four ZIPs contribute to Zn, Fe, Cu and Mn acquisition at the outer root domain

Zinc (Zn), an essential micronutrient, plays a crucial role in plant development. However, the specific transporters involved in Zn uptake from the soil remain unclear in dicotyledonous. Using promoter-reporter lines in Arabidopsis thaliana, we identified several ZIP (Zn-regulated transporter, Iron-regulated transporter (IRT)-like Protein) family members that are expressed in the epidermis and potentially involved in Zn acquisition from the outer root domain. ZIP2, ZIP3, ZIP5 and ZIP8 predominantly localize to the plasma membrane of epidermal and cortical cells, supporting their potential roles in metal uptake from the soil. Through physiology studies, ionomic profiling and genetic analysis, we determined that ZIP3 and ZIP5 are key contributors to Zn acquisition, while ZIP2 and ZIP8 are primarily involved in copper (Cu) and iron (Fe) acquisition respectively. Notably, ZIP3 and ZIP8 exhibit outer polarity in root epidermal cells, similar to IRT1, underscoring the significance of transporter polarity in mineral acquisition. These findings provide new insights into the mechanisms of metal uptake in plant roots and offer potential strategies for biofortification to enhance metal content in plants.

plant biology↗

bioRxiv2024

Directional Cell-to-cell Transport in Plant Roots

Cell-to-cell communication is critical for multicellular organisms. In plants, plasmodesmata--cytoplasmic channels--enable molecular transport between adjacent cells. In roots, this transport is predicted to be essential in nutrient acquisition and delivery to the vasculature. We demonstrate that plasmodesmatal transport persists in differentiated roots, despite apoplastic barriers such as Casparian strips and suberin lamellae in the endodermis, suggesting plasmodesmata as the sole pathway for water and nutrient flow at this stage. We also reveal a developmental switch in plasmodesmata function resulting in an unidirectional transport in differentiated roots. A genetic screen identified mutations that disrupt this directionality, leading to bidirectional transport. These mutations correlate with larger plasmodesmatal apertures, linked to defects in pectin composition and cell wall organization. This discovery underscores the role of plasmodesmatal aperture regulation and pectin in controlling directional transport. Our findings provide insights into plasmodesmata function and their regulation in roots.

plant biology↗

bioRxiv2021

Repression of the Hox gene abd-A by ELAV-mediated Transcriptional Interference

Intergenic transcription is a common feature of eukaryotic genomes and performs important and diverse cellular functions. Here, we investigate the iab-8 ncRNA from the Drosophila Bithorax Complex and show that this RNA is able to repress the transcription of genes located at its 3 end by a sequence-independent, transcriptional interference mechanism. Although this RNA is expressed in the early epidermis and CNS, we find that its repressive activity is limited to the CNS, where in wild-type embryos, it acts on the Hox gene, abd-A located immediately downstream of it. The CNS specificity is achieved through a 3 extension of the transcript, mediated by the neuronal-specific, RNA-binding protein, ELAV. Loss of ELAV activity eliminates the 3 extension and results in the ectopic activation of abd-A. Thus, a tissue-specific change in the length of a ncRNA is used to generate a precise pattern of gene expression in a higher eukaryote.

genetics↗